WILDERNESS SST NOTES
SST Information from QRP-L
AL7FS Jim Larsen
1. Subject: SST parts list/schematic error: output low-pass filter
2. Subject: SST article typo: 40m novice-band version VXO range...
3. Subject: SST: First production unit completed!
4. Subject: SST transceiver theory note: receiver front-end response
5. Subject: SST: First QSO on 30m version (WL7VO), plus misc. factoids
6. Subject: KC1 FREQ. COUNTER NOTE (w/SST): Simple way to improve VFO
signal
7. Subject: SST #1
8. Subject: re: SST #1; how to increase power
9. Subject: Re: Extending the SST Frequency Range
10. Subject: SST on the Air!
11. Subject: SST-40M On the Air
12. Subject: 20 Meter SST done
18. Subject: Re: HELP, my SST howls
19. Subject: SST-13 < problem with the audio level of the "sidetone"
being very hot>
20. Subject: Re: SST-13 < problem with the audio level of the
"sidetone" being very hot>
21. Subject: Re: SST-13 < RIT board for the NE4040 for use in SST>
22. Subject: SST Howls < optional DC filter can be installed to prevent
the oscillation>
23. Subject: SST howells < Another thing you can try>
24. Subject: SST Howls (Update) < Terry (W0OFR) mod worked!>
25. Subject: SST & KC-1
26. Subject: Re: SST &KC-1 < Is your ground lead short?>
27. Subject: SST 20 - de N3XRV < sounded a bit muddy (400Hz?) so I
changed>
28. Subject: In praise of the SST-20
29. Subject: Re: Noise reduction w/ LM386
30. Subject: BuzzNot noise blanker < installed it in my SST on 20M>
31. Subject: Re: SST ABX Mod
32. Subject: Using TiCK with the SST
33. Subject: More TiCK/SST Mods
34. Subject: Another SST is Born
35. Subject: Re: Fw: SST Tuning Range
36. Subject: Re: SST Tuning Range
37. Subject: SST not a toy!/SST mods summarized...
38. Subject: W6EMD mods summary
39. Subject: LM386
40. Subject: Re: LM386
41. Subject: Re: SST-20 mods query from AL7FS
41. Subject: Re: SST-20 mods query from AL7FS
42. Subject: SST 2 diodes mod.
43. Re: SSTs Changing Headphones
44. Subject: SST Varactor Switching
45. Subject: SST VXO Problem
46. Subject: Re: SST & TiCK
47. Subject: "Choking" the SST
48. Subject: Re: SST Tuning Mod revisited
49. Subject: The HB Sprint and the SST
50. Subject: SST-Internal Batteries
51. Subject: "Potential" Super SST
52. Subject: Re: "Potential" Super SST
53. Subject: Re: SST - working (replace the PA with an MRF 237)
54. Subject: SST for WWV 10.000 Mhz
55. Subject: Re: SST/40 Question (SST seems to drift a bit)
56. Subject: Simple Superhet Transceiver SST
57. Subject: SST/20 Question (very (*VERY*) loud blast of noise.)
58. Subject: SST-40 (change C10 to 22pf to increase side tone )
59. Subject: sst (Lots of notes from N6KR, Wayne)
60. Subject: SST 20 mods, thoughts...
61. Subject: Re: SST 20 VXO range
62. Subject: sst 40M audio problems-howl
63. Subject: Re: SST Mods URL (Fall issue of NorCal QRPp has my SST
mods)
64. Subject: Re: SST: Greatly improved VXO Range (thanks, N6GA!)
65. Subject: SST: Greatly improved VXO Range (thanks, N6GA!)
66. Subject: SST VXO Range (Thanks W6RCL!)
67. Subject: SST XCVR SURVEY: your input needed for next release
68. Subject: SST Coyote Killer -- One Easy Step
69. Subject: Expanded SST Freq Coverage
70. Subject: SST problem (most common parts for failure when hooked up
backwards)
71. Subject: Re: SST problem
72. Subject: XMAS SST and winding Toroids.
73. Subject: Re: SST Frequency Range Modification
74. Subject: SST (Discrepancy on rfc-2 (1mh)
75. Subject: Just-built SST and Frequency Range
76. Subject: just-built sst and Frequency Range answer
77. Subject: SST Mods - xtal filter
78. Subject: Another SST on 20 meters -- and a few questions...
79. Subject: Re: Another SST on 20 meters (answers)
80. Subject: SST AF Gain and Monitor Tone Problem identified
81. Subject: Frequency Range Adjustment Parts change
82. Subject: SST not quite there, help (freq. Range and AF levels)
83. Subject: Moving SST to 15mtrs
84. Subject: Move 20mtr SST to 15mtr: component values (also 87)
85. Subject: sst vxo (to extend vxo range)
86. Subject: SST sidetone (info from N6KR, Wayne) via AB7CE
87. Subject: moving SST to 15mtrs (another component change) (see 84)
88. Subject: TiCK Audio in SST? (Question but no answer: Ask Steve?)
89. Subject: Mounting a Tick/K8+
90. Subject: Another SST lives (Frequency Range issues)
91. Subject: NC 40A versus SST - per N6KR Wayne
92. Subject: AW: alternate crystals for SST/40
93. Subject: Re: SST/40 bandwidth issues
94. Subject: Tick keyer into SST (will have to ask for the solution)
95. Subject: Re: sst question... 8V to NE612's and LM386.
1. Subject: SST parts list/schematic error: output low-pass filter
Date: Wed, 30 Apr 1997 08:54:11 -0800
From: svecbrdk@well.com (L.Svec,W.Burdick)
There's an error in the SST schematic and parts list. For the 40 meter
SST, L2 and L3 should have 18 turns, or approx. 1.3 microhenries. These
are the same values used in the 40A and Sierra. (Thanks to Bob Parks,
K6AEC, for catching this.)
Also, the crystal filter circuit has been improved since I wrote the
article, and now has L-C impedance transformation at either end. I'll
post the new values for this circuit soon.
Wayne
N6KR
2. Subject: SST article typo: 40m novice-band version VXO range...
Date: Wed, 30 Apr 1997 20:37:41 -0800
From: svecbrdk@well.com (L.Svec,W.Burdick)
...is about 7.105 to 7.115, not 7.110.
Wayne
N6KR
3. Subject: SST: First production unit completed!
Date: Wed, 14 May 1997 01:49:50 -0800
From: svecbrdk@well.com (L.Svec,W.Burdick)
Hi all,
I just built the first SST using the revised schematic, production PC
board and cabinet. Looks and works great. Made three test QSOs late
this evening (AZ, TX, WA), all coming back on the first call. I'll try
to hook up with a local tomorrow to get a detailed signal report.
I built the 40-meter version first, but I'll build 30 and 20-meter
versions ASAP. Some preliminary observations on the 40m unit:
* 2.3W out max at 14VDC (this can be increased with one resistor change)
* QSK is fast enough to hear between the dots at >35WPM, with no thumps
* filter bandwidth is about 300Hz at -6dB; peak is near 600Hz
* opposite sideband suppression is >50dB (better measurement later)
* noise floor is extremely low; "sounds like" -140dBm, but I'll
post an actual measurement later (let's put it this way: with the
antenna disconnected, I hear nada!)
* quick test with the KC1 showed no audible receiver interference w/KC1
running
* turns out that the "S-meter"/AGC LED was supposed to be a
high-efficiency red type, not a regular red type. I have to call Bob
Dyer first thing tomorrow to have him change the Mouser order :)
Could have been worse....
I'd like to once again thank those of you who ordered early for being
patient. Doing things right takes time!
73,
Wayne
N6KR
4. Subject: SST transceiver theory note: receiver front-end response
Date: Wed, 21 May 1997 08:01:14 -0800
From: svecbrdk@well.com (L.Svec,W.Burdick)
In the SST article in QRPp, my explanation of how the SST's receiver
front-end filter works left too much to the imagination. Funny how when
you take away some parts, the thing gets more complicated ;) Here's
how it works:
C1 and RFC1 actually form a *series-tuned* circuit, with RFC1
effectively connected to AC ground by C3 (.01uF). Since the signal is
shunted to ground by C3, the load for the tuned circuit is U1 (NE602),
via C2 (5pF).
At the junction of C1/RFC1, the impedance is very high, and C2 provides
a good match to the 1500-ohm input impedance of U1. On transmit, D1
shunts C1/RFC1 to ground so the series-tuned circuit has no effect.
When the series-tuned circuit is considered together with the low-pass
filter (C34/35/36 and L2/3), you find that the overall response on
receive is much more complex than with the series-tuned circuit alone.
It is a double-humped band-pass response, with the second hump's
location dependent on where the knee in the low-pass filter curve is
located. The 5-pole LPF greatly attenuates the image response, which on
40m is around 15.04 MHz.
Ideally, you want the low-pass filter's knee to be at the same location
as the peak of C1/RFC1. While it is possible to select components for
the low-pas filter that result in an optimal band-pass peak at the
operating frequency, this compromises transmit performance. As an
example, consider C34=C36=1000pF, C35=1500pF, and L2=L3=1100nH. These
values work well on receive, but show a high SWR and excessive ripple on
transmit.
Modelling
If you're interested in modelling this circuit, you'll need to also add
in the parasitic capacitance for RFC1 (about 6pF in parallel), as well
as about 4pF for pin 1 of the NE602. On 40 meters, C1's value is around
24 pF at resonance; RFC1 is 15uH.
For the low-pass filter, I used C34=C36=330pF, C35=820pF, and
L2=L3=1.4uH, which provides a good match from the 2N3553 to a 50-ohm
load. This places the low-pass knee somewhat above 7MHz. You may want
to plug in the low-pass values I mentioned earlier to see the effect of
moving the knee down in frequency.
In order to make the model match reality on receive (with the actual LPF
values), I had to include some capacitance for the zener diode and the
2N3553's collector. I used about 400pF, which may be on the high side,
and eventually I'd like to use a more accurate figure. (If anyone else
tries to model the circuit, please let me know.) In the real SST, the
second hump is near 8.5MHz and about 10dB below the 7MHz peak of the
series-tuned circuit, and the model agrees when I add the extra 400pF
at the zener side of the LPF.
73,
Wayne
N6KR
5. Subject: SST: First QSO on 30m version (WL7VO), plus misc. factoids
Date: Thu, 22 May 1997 01:13:57 -0800
From: svecbrdk@well.com (L.Svec,W.Burdick)
More SST news (all good) from SST headquarters in Belmont, CA.
I finally had a chance to put the 30m version of the SST on the air.
Conditions were marginal, but I hooked Dick, WL7VO, in Chicken, AK on
the first call. 439 report--not bad for 2W and a vertical. No luck
calling the ZL4 after that....not yet, at least.
Here are a couple of measurements taken on the completed 30-meter
version w/13.8V supply:
Transmit power out, max: 2.7W
Transmit PA efficiency: 77% at 2.O W out
VXO range: 10.105-10.118 w/MV209 varactor
10.097-10.112 w/MVAM108 varactor
Note: High end of VXO range can be moved up to
10.123 with an inductor change
Receiver selectivity: approx. 300Hz at -6dB (AGC off)
Wayne
N6KR
6. Subject: KC1 FREQ. COUNTER NOTE (w/SST): Simple way to improve VFO
signal
Date: Tue, 3 Jun 1997 00:22:35 -0800
From: svecbrdk@well.com (L.Svec,W.Burdick)
Hi all,
The frequency counter section of the KC1 is typically coupled to a
strong VFO or VXO using a small capacitor. However, in the SST, the VXO
signal is both high in frequency and low in amplitude, so I needed a
different method. The technique I'll describe may work in other KC1
installations, too.
NOTE: These instructions will be included in the SST manual.
Here's the trick:
Instead of connecting the KC1 directly to the VXO, I connected it to the
output of the receive mixer's on-chip buffer (U1, NE602 or NE612, pin
7).
Using this buffer effectively isolates the VXO from the KC1. However,
due to the low VXO amplitude, a large (100pF) coupling cap is needed
from U1 pin 7 to the KC1. This large cap causes the KC1 to load down
the buffer, reducing its output voltage. What to do?
An often-used trick with the NE602 to improve oscillator starting is to
put a resistor from pin 7 to ground. What I discovered is that this
trick also stiffens up the buffer, allowing it to tolerate the large
coupling cap for the KC1 without much reduction in signal. (The current
drain of the '602 goes up slightly when you do this--less than a
milliamp.) There is no other apparent effect on the NE602's
performance.
Besides using the trick above, there are a couple of other steps you'll
need to perform when installing a KC1 in an SST. Here's the complete
list:
1. Change R3 on the KC1 from 3.3K to 470 ohms. This greatly improves
the gain of the KC1's on-board VFO amp at high frequencies. (It also
adds 3mA to the KC1's current drain. Can't get something for
nothing....)
2. Use a large value for the VFO coupling cap (Cv). 100pF seems to
work fine. Connect the SST to pin 7 of the receive mixer (NE602)
through Cv as shown in the KC1 manual. This is the normal connection
point, indicated by "CTR" on the SST PC board.
3. On the SST, add a resistor from pin 7 of U1 to ground to lower the
impedance of the NE602's on-chip buffer. 15K will do the trick.
4. Other aspects of the KC1 installation in the SST are similar to the
NorCal 40/40A, except that I recommend NOT using the KC1's MUTE output.
Just leave it disconnected. As for the sidetone coupling cap, try
.01uF.
The KC1/SST combination installed as described draws 22 to 23mA from 12V
when using headphones. You can shave a couple of mA by substituting a
"micropower" 5V voltage regulator for U2 on the KC1.
73,
Wayne
N6KR
7. Subject: SST #1
Date: Mon, 9 Jun 1997 14:29:01 +0100
From: adams@chuck.dallas.sgi.com (Chuck Adams)
Gang,
Doug sent me email saying that he had good news and he had bad news.
Good news --- he was bringing SST #1 from the production of kits and I
was going to get to build it. Bad news --- the rig was his and he gets
to keep it. :-) followed by :-(
After dinner Doug and I head for the house which is on the other side of
Dallas from the hotel. We get setup and here is the scenario. We have
a complete kit (many thanks to Wilderness Radio and Bob Dyer for doing
this) but the manual was not back from the printers or whatever, so all
we have is a bag of parts and a hand written parts list that Doug did
from the only copy of a list that Bob had. :-) Now, there was a
schematic in the Dec issue of QRPp from NorCal, but that is on the other
side of the house, for the time being. So Doug calls out the part
number, say R1, and hands me the X-ohm resistor and I install it using
only the silk screen parts numbers. It takes us a little of 1.5 hours
or so to do this. Time may vary..... etc. Can't do a review of the
manual as I have not seen it. But you don't need the manual if you have
the parts list as witnessed by the building that took place for this
rig.
Parts are good quality and the board is excellent. More detailed review
to follow when I get my 30M version. Only problems encountered and they
are minor, but be warned. Board has two R12 labels. One should be R1.
You won't get this mixed up as one is 1/8W resistor and the other is
a board mounted variable for the RF gain. No biggie. The other is the
PC board mounted slide power switch has the three switch connections and
two legs that need to be soldered to the board. The two legs are
slightly closer together than the holes on the board, so you have to
file/scrape the inside area of the legs to get a neat fit, but
experienced builder and careful builder will lose just a little time in
doing this.
There are two trimmer caps to peak receiver input and to tune a LC
bandpass on the transmitter side for the only two adjustments for tuning
up the receiver and the transmitter. I found that the leg separation on
the parts and the board are slightly off and the caps did not sit flat
on the board and the pins did not protrude all the way out the bottom
of the board, but they did solder nicely anyway.
After getting the board assembled and using the toothbrush to remove
the water soluable flux we are now ready for the smoke test. So get
the gel-cel and measure about 12.33V or so and attach the power
cable we are ready to fire the puppy up (it is smaller than the NC40a)
and see how it plays. Power on (the power switch is in the down
position gang) and we hear a hiss in the headphones. Good sign and
I don't hear any frying or smell any thing burning (that comes later).
Get the Tek 191 RF generator and sweep the 20M band (did I tell you this
SST was for 20M?) and hear a signal. Proceed to peak (at this point I
did have to treak down the hallway to the bookcase and get the QRPp
issue with the schematic) the receiver input. Seems to be sensitive
enough.
Now get OHR WM-1 and dummy load and peak output of transmitter. Getting
about 1W out. Now at this point in writing this, let me predict. We
are going to see tons of mods for this rig or add-ons 'cuz there are not
many serious milliWatters in this group. :-) Output test at this time
is at a battery voltage of 12.3V or so and I did not have rig in my
possession long enough to do the detailed K5FO experiments, so later
we'll see and remember this is at 20M where things get a little more
difficult at the RF level.
With Heath freq meter we get a range of 14.045 to 14.059MHz, so not bad
for VXO again on 20M.
During this building and testing I had turned on the Philips PM-3266
scope to look at waveforms and use for peaking. At about the time we
powered up the SST and were peaking stuff and at the time I started
RF output I heard a 'pop' and then the smell of something burning.
I probably lost a heartbeat there somewhere for fear that I had
personally fried something with the screwdriver that I was using to
key the rig (hey, you didn't expect me to go one more time across the
house to get a keyer, paddles, and cables and come back and lose all
that time, did you? I knew you didn't.). Well, it is another prime
example of what I call the 'visitor effect', known to this group as
Murphey's Law. The scope power supply decided to show off for Doug
and went belly up. Not to worry, got a Tec 475 at the HamCom fleamarket
and we'll let you know later in the week or early next week on both
the condition of the insides of the Philips and the Tek 475.
Doug carried the SST around and used it for show-and-tell all over the
place in Arlington and Dallas. :-) Sunday afternoon after the meet
he and I hooked it up to a real antenna and heard VE5, EA1, EA2, and
all up and down the east coast and central US. I picked a clear freq
and called CQ on and off for 30 minutes or so, but noone worked.
Band may have not been in good shape for QRPp as I was doing 900mW at
the time as measured on the WM-1.
Because of the time constraints, I don't have a relative comparison
on RCVR sensitivity to other rigs, so I'll leave the 20M version for
someone else to do. I'll do the 30M and we will see postings on
others experiences. That is partly what this group is all about.
Selectivity seems to be excellent from first impressions.
Doug wasn't about to leave the rig here in TX (you know how the CA vs.
TX thing goes) for any period of time, so at the time of this posting
Doug and JoAnne are on a flight to KS and the SST rig is on its way
to a worldwide adventure over the next year.
Thanks to Doug for giving me a chance to see first hand what we can
expect to see from Wilderness Radio shortly. It was fun kit to build
and the early buy of $69 looks like a good deal and our thanks to
Wayne Burdick for the design and Wilderness Radio for the production
of the kit.
FYI
dit dit
Chuck Adams K5FO CP-60 adams@sgi.com http://reality.sgi.com/adams/
8. Subject: re: SST #1; how to increase power
Date: Tue, 10 Jun 1997 08:13:09 -0800
From: svecbrdk@well.com (L.Svec,W.Burdick)
Folks, Chuck and Doug didn't have the SST manual to look at, but you
will. The manual has a few suggestions for increasing power output,
including the following: reduce the value of R10 from 220 to 150 or
even 120 ohms.
At 14V, expect about 2W out or more on each band.
I expect Bob to begin shipping the kits in a day or two.
73,
Wayne
N6KR
9. Subject: Re: Extending the SST Frequency Range
Date: Wed, 11 Jun 1997 08:43:05 -0800
From: svecbrdk@well.com (L.Svec,W.Burdick)
Hi Paul,
To get 40 kHz from the SST you would have to modify the VXO, making it a
VFO instead. The 40-meter version is the only one that this would work
on, since it's the only band where the VFO freq. would be low enough to
be stable (i.e., about 3MHz). I have not attempted this, partly because
the rig is not inteded to be a be-all radio. I'm sure someone will,
eventually.
You'd have to use the varactor tuning, still, but add a large toroid and
a few polystyrene caps, then hand-adjust the toroid until you get to the
desired range. One problem is that the VXO tuning pot is a small one,
not really suitable for tuning a wide range because it is mechanically
not as "clean" as a larger pot. You might be able to find a small 10-
turn pot that fits in the same space, but it won't be easy.
73,
Wayne
>Wayne:
>
>Do you think it will be reasonably possible to extend the frequency
range >of the SST in a similar manner as the Norcal 40? In a previous
posting, >you indicated that limited extended coverage was possible by
"bending" a second crystal or varactor position and adding a switch.
>
>It would sure be nice to have the 40M version cover 40 or 50 kHz! What
do
>you think?
>
>-Paul, W9AC (Ex-N9AZ)
10. Subject: SST on the Air!
Date: Thu, 12 Jun 1997 20:48:17 -0600
From: "Bob Follett"
Gang:
>From Post Office delivery this afternoon to now -- 4.5 hours
construction, the
SST is on the Air!
A Quick construction report:
1. I don't think we will be generating as many modification/how do I
change this? messages with this rig as the 40'9er or 38S. Of course
there is always room for the keyer/noiseblanker/frequency
readout/tuner/battery and solar charger additions :-)
2. I found zero errors in the manual.
3. I do have an accurate L/C meter now, and found I needed one T removed
from L2 & L3, the output filters, to get down to specified value.
4. I found the BFO too low in frequency. Wayne mentions using a trimmer
instead of a fixed cap, but I reduced the 33pF to 22pF and got it about
equal to the side tone, where I liked it.
5. The frequency range, using the 108 varacter, is 7.027 to 7.039kHz.
I'll try to raise/expand that tomarrow (You really shouldn't widen the
tuning range -- with the very sharp filter and small tuning knob, the
signals pop in and out as it is. Perhaps Wayne's idea of using both
diodes with the s/w is a good answer, but all I want to do is raise the
freq. up to 7.043+
6. I matched the IF crystals and caps to optimize the IF filter design
--- Probably not a good idea. My filter is VERY narrow currently --
guessing, in the 200-250hz range. I'll either widen with different
caps, as Wayne outlined, or add the VBX which I have on both my Sierra
and 40A.
7. The Xmit tuned up immediately to between 2.6 to 2.8 watts (I need to
measure with the scope instead of the WM-1) Very nice! Sidetone is
totally w/o clicks/thumps, and other assorted garbage.
8. Needless to say, with VXO, the rig is very stable. Oh yes, and the
AGC really works well.
Now to add a keyer, 9V supply, swap out the voltage regulator for 9V
operation, etc. Oh yes, and the great paint-the-case debate. (Maybe we
could get a group rate on a mass-anodizing somewhere) I'll have the
front and rear panels scanned in to CorelDraw 5, if anyone needs them in
that format. (can try .TIF, but generally don't like the conversion to
bitmap)
In summary, a great rig! Thanks Wayne and Bob D. I am really looking
forward to taking it backpacking. I think my PL259 plus BNC adapter
weighs more than the rig!
73, Bob
----------------------------------------------------------------
Bob Follett AB7ST, QRP-L # 129, NorCal, ARCI, 10-10, ARS
2861 Estates Dr. VOICE: 801.649.6457
Park City, UT 84060 E-mail: bfollett@ditell.com
11. Subject: SST-40M On the Air
Date: Sat, 14 Jun 1997 03:47:30 -0400 (EDT)
From: Steve Bornstein
G'day Gang,
Completed and tested my SST-40M rig in the wee hours. Rig tunes 7030 to
7039.9 with D4B installed. (Am going to move it up a bit with D4A).
Output power is about 2.5 watts with R10 at 120 ohms (Operating on
13.5v).
Power adjustment pot will adjust power down to nil. Phones audio is
sufficient (using Yaesu phones). Made first contact with WB4KKL in FL at
0620 hrs Z. A nice haul from Columbus, OH. Sigs varied from initial 459
to 589. FL station was troubled by static crashes. Painted enclosure by
first spraying with zinc chromate primer followed by black for enclosure
halves and grey for front and rear panels. I will report on further
progress, but first impressions are all positive. Assembly is a snap and
manual is excellent. Given it's very small size and minimal current draw
the SST is an ideal take along rig.
73 DE K8IDN STEVE QRP-L 331, ARCI 9059, NORCAL 1717, MIQRP, FISTS 2441,
GQRP 8332, CQRP 1
12. Subject: 20 Meter SST done
Back on 18 June (Daily Digest 761, message #21579), NA5N gave a
detailed technical report on an SST. Among a whole lot of other
things, he mentioned the harmonic suppression seen on a spectrum
analyzer. A while back, WA4KAC (Walt Thomas) let me borrow his
40M SST and check the spectrum at work. I went into it in more
detail, measuring both the second and third harmonics at a variety of
power supply voltages. Here are the details in case anyone is
interested.
Walts rig is pretty much stock, although he did experiment with a
variety of final transistors and ended up with a 2N5262 that I gave
him once, since it provided a bit more power. He mentioned that he
simply wound the toroids as specified in the manual and did not
experiment with compressing and squeezing the turns to get maximum
power. (I wanted to keep the rig longer and remove the coils and caps
in the filter to check the actual values, but he wanted to get the rig
back on the air.)
Equipment setup--HP E3630A variable DC power supply, HP 8590B
spectrum analyzer, .Weinschel 30 dB attenuator (50 watt rating!)
model 24-30-34. The output of the SST was fed through the
attenuator into the spectrum analyzer. Power levels given are in dBm,
or in relation to 1 milliwatt at 50 ohms, and were later converted into
watts. Precise attenuation of the Weinschel was not checked since I
wasn't interested that much in the fundamental power, just the
harmonic suppression, and is presumed to be the nominal 30 dB. The
harmonics are given in negative dBc, or dB below the carrier level.
DC volts Power Power 2nd harmonic Third harmonic
dBm watts -dBc -dBc
13.8 34.4 2.75 37.3 61.3
12.0 33.2 2.09 37.4 61.0
11.0 32.48 1.77 37.44 60.8
10.0 31.59 1.44 37.7 60.0
9.0 30.85 1.21 37.66 59.55
8.0 29.53 0.90 37.77 58.8
7.0 28.27 0.67 37.76 58.0
6.0 27.1 0.51 37.62 57.5
Although the sweep on the analyzer was set wide enough to see
higher harmonics, they were lost in the noise level (which was around
70 dB below the carrier level when the voltage was set to 12.0). No
attempt was made to monitor the signal for quality or otherwise check
performance at the various voltages. The sole purpose of the test was
to observe the harmonic suppression. Interestingly, the second
harmonic remained relatively constant (and easily legal since the FCC
requirement for under 5 watts is 30 dB minimum), while the third
harmonic showed a steady deterioration as voltage went down. I'm
not going to worry about that too much, considering that it still
exceeds the FCC spec by at least 27 dB :-)
73 and Queue Our Pea DE WA8MCQ wa8mcq@abs.net
16. Subject: HELP, my SST howls
Date: Tue, 15 Jul 1997 22:18:21 -0700 (PDT)
From: Kory Hamzeh
I just finished build my 30M SST, it seems to work well, except for the
fact that the receiver starts to howl (go into feedback or oscillation)
when I tune to a strong signal and the volume is turned all the way up.
If I back down on the volume, the howling stops. While it is howling,
the AGC LED is pegged.
This is not a stock build, I've done the following mods:
1. The PA is a MRF237
2. C10 is a 50pf trimmer. What is the correct procedure for determining
the optimum setting for C10?
3. I've done the ABX mod as described in the SST manual.
4. I've installed a 39uh choke between X4 and C10.
5. I've removed one turn from L2.
Other than that, its pretty much stock! :-)
The audio sounds a bit muddy, as compared to my Sierra. Is this normal?
Any help would be greatly appreciated.
Thanks,
Kory
AC6RN
17. Subject: SST-Lucky #13!
Date: Wed, 16 Jul 1997 01:35:29 -0700
From: talljazz@teleport.com (Dan Presley)
Lucky #13 SST 20 is now alive & well (I think!). This is the kit I
recieved as a prize for the "Bumblebee" event (to be held July 27) -I
was the 13th person to sign up for the event through the Adventure Radio
Club. Anyway, I finally finished the radio, and discovered I had
intalled IC U5 backwards!I was able to unsolder (next time, sockets!),
and even though I didn't think the chip would withstand being yanked on
and slightly chipped (no pun intended), I was able to reinsert it
correctly, and it seems to work fine.Tuning range is about 14040-058 w/
a 4.7 uH & a 1uH together at RFC 3 , so I may try to lower it a little
more to move the range to above 060. Please listen for me tomorrow (Wed
7/16) at about 1700-1900 UTC around 14055 +-. This rig will be "Bumble-
beeing" if all goes well! Thanks again to Russ & crew for the nice
prize, and Russ, I will be contacting you soon for more detail on
our 'secret location' for July 27!
Dan N7CQR
18. Subject: Re: HELP, my SST howls
Date: Wed, 16 Jul 1997 11:07:27 -0700
From: chunt@macromedia.com (Christian Hunt)
I have a similar problem on my 40m SST. If I have the AF gain fully
clockwise and I key, after releasing the key, I get a howl that
gradually fades away. It's loud enough to cause a buzz in my headphones.
Mine is pretty much stock except has a wider filter. This doesn't seem
to be the cause as the howling occurred without it as well.
73, KF6IHU
19. Subject: SST-13 < problem with the audio level of the "sidetone"
being
very hot>
Date: Thu, 17 Jul 1997 00:41:10 -0700
From: talljazz@teleport.com (Dan Presley)
Well-first QSO w/ my SST-20-13 was about 10 blocks away! But,it works
quite nicely.A few comments- freq coverage is from 14052-060 with 4.7uH
choke for RFC 3, and 14044-055 with other varactor (I have them
selectable with toggle switch mounted on the front). The mod for tuning
linearity (18K resistor across R4) works very well, and I had no trouble
with sharp tuning. Audio is a bit lower than I prefer, but will leave it
as is for now. I am having a problem with the audio level of the
"sidetone" being very hot, and I have to back off the audio gain before
xmit or my ears are blown off!I realize that it's actually monitoring
the output- Anyone else experience this, or is it unique? Other than
that, it recieves quite well, and I'm anxious for condx on 20 to improve
for more qsos!
Dan N7CQR
20. Subject: Re: SST-13 < problem with the audio level of the
"sidetone" being
very hot>
Date: Thu, 17 Jul 1997 08:48:28 -0400 (EDT)
From: Chris Cartwright
Dan,
I had the same thing with the 30M version. I opened the IF filter up as
noted in the manual, and it improved the audio, and seemed to reduce the
sidetone a bit. Or maybe I just don't need as much volume, or I got
used to it:) I've see a few posts about the wider filter being nicer to
listen to. I've been having a blast with the little thing, gotta get
that KC-1 in there though... and ABX... and RIT... and...
-- Chris Cartwright, Technical Engineer | ccart@vidtel.com
--
-- N3XRV QRP WAS 17/9 (w/c) | ccart@erols.com
--
-- QRP-L #655 NORCAL #1891 QRP-ARCI #???? |
http://dns.vidtel.com/~ccart --
-- WIMPS Q's=04 30M=04 17M=00 12M=00 STATES=03/00/00 DX=00/00/00
QSL's=00 --
21. Subject: Re: SST-13 < RIT board for the NE4040 for use in SST>
Date: Thu, 17 Jul 1997 09:57:21 -0700 (PDT)
From: Kory Hamzeh
On Thu, 17 Jul 1997, Chris Cartwright wrote:
>
> I had the same thing with the 30M version. I opened the IF filter up
as > noted in the manual, and it improved the audio, and seemed to
reduce the > sidetone a bit. Or maybe I just don't need as much volume,
or I got used > to it:) I've see a few posts about the wider filter
being nicer to listen > to. I've been having a blast with the little
thing, gotta get that KC-1 in there though... and ABX... and RIT...
and...
>
Now that you mentioned RIT ....
I ordered the RIT board for the NE4040 from Dan's Small Parts. Once I
get my SST to work properly (no howling!) I will try it and let you guys
know how it works.
Kory
AC6RN
22. Subject: SST Howls < optional DC filter can be installed to prevent
the oscillation>
Date: Sat, 19 Jul 1997 02:27:05 EDT
From: tshilhanek@juno.com (Terence J Shilhanek)
My SST 40m version also howled when the audio gain was at maximum.
Looking at the application notes on the LM386 audio chip that is in the
SST, I noticed that there is a comment that if the chip oscillates then
an optional DC filter can be installed to prevent the oscillation. The
filter is only a resistor and a by-pass capacitor placed in the lead
supplying power to the chip. I have installed the modification and it
seems to work. The changes can be done on the etched side of the pc
board.
1. cut the trace going to pin 6 of U3
2. solder a 100 ohm 1/4 watt resistor from pin 6 of U3 to the
contact next to pin 1 of U3 .
3. solder a .1mf disc cap from pin 6 of U3 to pin 4 of U3
Terry, W0PFR
23. Subject: SST howells < Another thing you can try>
Date: Sat, 19 Jul 1997 14:24:49
From: Steven Weber
Another thing you can try is adding a BFC say 470 ufd to 1000 ufd across
the raw DC power supply leads. Ideally, wire the cap directly across the
power pins of the LM386. A small resistor, say 1 to 10 ohms in series
with the plus supply pin might also help. (with the cap across the audio
amp power pins)
Steve, KD1jv....In the White Mountains of New Hampshire
"Melt Solder"
24. Subject: SST Howls (Update) < Terry (W0OFR) mod worked!>
Date: Mon, 21 Jul 1997 17:48:22 -0700 (PDT)
From: Kory Hamzeh
Thanks to Terence W0OFR, I tried the attached mod and it worked! Also,
another note, while in radio shack picking up the parts for this mod, I
picked up a Nove 43 headphone per someone's recomendation on this list.
Anyway, I tried the headphone before the applied the mod, and the
howling does not happen with the Nova 43 (actually, there is a short
burst when the rig is first turned one, then the howling stops very
quickly).
By the way, I highly recommend the Radio Shack Nova 43 headphones. Very
nice and sensitive.
Thanks Terence!
73,
Kory
AC6RN
25. Subject: SST & KC-1
Date: Thu, 24 Jul 1997 09:20:02 -0700
From: talljazz@teleport.com (Dan Presley)
Has anyone had problems installing a KC-1 keyer in the SST? I have a 20M
SST and KC-1 that seems to be misbehaving-won't key consistently from
the paddle, and keeps spitting out the letter "D", and then freezing
up-sometimes it will send a string of dits until I shut the rig down. I
have isolated the paddle lines with ferrite beads & .01 caps in case of
RFI, but this still happens even with reduced power out on the SST. Any
ideas?
Dan N7CQR
26. Subject: Re: SST &KC-1 < Is your ground lead short?>
Date: Thu, 24 Jul 1997 13:14:25 -0700 (PDT)
From: "David D. Meacham"
Dan,
I have no problems with the KC-1 in my 20m SST. Maybe yours is picking
up some RF. Is your ground lead short?
72, Dave, W6EMD
27. Subject: SST 20 - de N3XRV < sounded a bit muddy (400Hz?) so I
changed>
Date: Fri, 25 Jul 1997 22:49:32 -0400 (EDT)
From: Chris Cartwright
Just got the 20M SST from K7SZ, sounded a bit muddy (400Hz?) so I
changed C10 from 33pF to 18pF and sounds much more gooder :) Set the
output to one watt, and connected it to a hamstick, stuck in the ground
in my front yard, with three radials, and came within microwatts of
working AC4YW in Florida (abt 800 mi). Even with a bunch of repeats,
just couldn't quite get there. With a straight key no less. Guess I have
a chance at the bumble bees this weekend. I just love this QRP stuff.
Sorry, just wanted spout off a little, I'm going back to sit in the
front yard play radio now...
Oh, for the curious: 18ma RX, 185mA TX@12V, 14.035-064 w/MV209
-- Chris Cartwright, Technical Engineer | ccart@vidtel.com
--
-- N3XRV QRP WAS 17/9 (w/c) | ccart@erols.com
--
-- QRP-L #655 NORCAL #1891 QRP-ARCI #???? |
http://dns.vidtel.com/~ccart --
-- WIMPS Q's=04 30M=04 17M=00 12M=00 STATES=03/00/00 DX=00/00/00
QSL's=00 --
28. Subject: In praise of the SST-20
Date: Wed, 30 Jul 1997 22:35:50 -0700 (PDT)
From: Alan Kaul
I can't say enough nice things about my optimized SST (using
Dave-W6EMD's mods -- and one of my own to increase the VXO tuning
14.046-14.063).
Terrific little rig!!!! Running about 3W output, 15V AC supply.
I've had only 4-contacts -- BUT WITH FOUR DIFFERENT DXCC COUNTRIES!
K0EVZ, SM5AGI, VE4GEC and VK2KM (the SM5 lost me in Euro QRM--but the
rest of the QSO's went to completion).
Three times I answered CQ's, once someone answered mine.
All QSO's between 0420Z and 0530z on 3 different evenings.
My sigs ranged from 589 to 529.
My antenna is an A3 tri-band Yagi at about 40-feet.
Wow!
[] kaul@netcom.com
29. Subject: Re: Noise reduction w/ LM386
Date: Fri, 01 Aug 1997 12:56:18 -0400
From: Randy Hargenrader
Hi Bob,
There are a couple of ways to reduce the high freq hiss
from the LM386. One is to use a small inductor (2.2mH) in series with
the output device (spkr or headphones). Another is to play with the
feedback circuit by using a "T" circuit as the feedback circuit.(two
resistors and a cap) You can also peak the audio response by putting an
inductor and capacitor in series to ground from pin 1.
Some circuits I've seen roll off the output with R/C networks.
I have component values for the inductor/cap to pin 1 if youre
interested.
--
73, (Sir)Randy WJ4P
Knightlites QRP-L #296 ARCI #9152 1996 40-9er High Scorer
30. Subject: BuzzNot noise blanker < installed it in my SST on 20M
Date: Mon, 14 Jul 1997 08:55:55 -0600 (MDT)
From: bcutter@teal.csn.net (Bob Cutter)
I cannot say enough about the BuzzNot noise blanker. I installed it in
my SST on 20M and it does an amazing job on my electrical noise.
Another great design from Wayne and available from Wilderness Radio.
72, Bob KI0G
31. Subject: Re: SST ABX Mod
From: "Paul Christensen"
Date: Sun, 22 Jun 1997 07:01:46 -0400
I just went through my notes....
In order to make the ABX mod work on the SST, you'll need to insert a 39
uH choke (molded or toroid) between C10 and X4. Additionally, it will
become necessary to add a 50 pF trimmer at in place of the fixed
capacitor at C10. Since there's such a tight fit between U2 and X4,
you'll need a really small trimmer cap. I've done the homework for you:
Mouser P/N 24AA024
This is a high quality ceramic trimmer and fits perfectly in place of
C10.
-Paul, W9AC
nnnn
32. Subject: Using TiCK with the SST
From: "Paul Christensen"
Date: Sun, 22 Jun 1997 07:11:35 -0400
I went out on a limb and tried something I hadn't done before.
Since the TiCK is rated between three and five volts, and the SST's
regulated voltage is eight volts, some form of voltage drop is required.
While it's possible to use the TiCK's 78L05 regulator (supplied with the
DIP-style kit), I chose to use two LEDs in series between the SST's
eight volt supply and the TiCK. I'm not sure what, if any additonal
current is spared by not using the additonal regulator, but it was an
interesting experiment nevertheless. If I get a chance, I'll measure
current consumption with both configurations. Until then, I plan on
leaving it this way in mine.
-Paul, W9AC
33. Subject: More TiCK/SST Mods
From: "Paul Christensen"
Date: Sun, 22 Jun 1997 08:48:50 -0400
Like the Like the Wilderness KC1, the Embedded Research TiCK has he
ability to inject sidetone audio into a transceiver. While I generally
like to keep the sidetone off and let the rig provide it's own sidetown
when available, it's still necessary to couple this audio into the rig
for programming puposes. Embedded's Piezo alternative just doesn't cut
it for me.
The TiCK manual states a value of a 1Meg resistor for R3 for use with
the Norcal 40A. The results in a very low sidetone audio level on the
SST.
Simply change R3 to 100K to form a more proportional voltage divider.
To my ears, this value provides a sidetone level that's "just right."
As an alternative, one could replace the TiCK's R2/R3 voltage divider
with a 100K micro-potentiometer. then you'll have the ability to set
the level anywhere you want it.
-Paul, W9AC
34. Subject: Another SST is Born
From: Craig LaBarge
Date: Sun, 22 Jun 1997 10:04:07 -0400
Gang:
My 30 meter SST kit arrived last week and I finally had some time
yesterday to build it. It took somewhere in the neighborhood of 4 to 5
hours to build and I encountered absolutely no problems whatsoever. All
the parts were there, instructions were excellent, alignment was
trivial, and it worked like a champ the first time I fired it up. The
case was a perfect fit (and even looks great with the unfinished
aluminum).
The only mod I made was to reduce the number of turns on L2 and L3 by
one. When I originally wound them with the specified 14 turns, the
inductance measured at 10MHz seem a tad high. 13 turns brought them in
a little closer to the specified .8 uH. I think mine measured at about
.9 or so.
Anyway, I get 2 watts out with a 13.6 volt power supply. Stable as a
rock and the receiver has plenty of audio. I opted to used "D4B" in the
VXO and the tuning range is as specified in the manual.
This morning I fired up the SST and heard a K5 station calling "CQ QRP"
and got him on the first call. He was down in MS and we had a nice chat
despite some very noisy band conditions and the fact that I was pumping
2 watts into my rainspout antenna. He gave the SST a clean signal
report.
So, Southeastern PA to MS wasn't a bad first QSO for the little SST.
I finished the SST just in time for some real field testing on an
upcoming vacation to the Outer Banks of NC. I think I'm going to have
some fun with this little rig. After I get back, I'll have to get it
painted and pretty it up a bit.
73, Craig WB3GCK
P.S. The only problem with the rig is that I tend to get hypnotized by
that flashing LED on the front panel!
35. Subject: Re: Fw: SST Tuning Range
From: "Bob Follett"
Date: Sun, 22 Jun 1997 10:44:54 -0600
Hi Ken:
Well, its sort of in the manual....
Wayne says you can install both Varacters to cover both their ranges.
He doesn't say how to do it.
Its just a matter of finding a reall small SPDT switch, drilling a hole,
then mounting both Varacters to the switch, hot side of each to the two
outer s/w poles. Then run a wire to the hot side of the PCB board to
the s/w center, and the ground side wire up to both ground sides of the
varacters. Its simple, other than planning where you want the s/w on
the panel.
I ended up with mine up high enough to clear the electrolitic caps on
the PC board behind the led.
73, Bob
----------------------------------------------------------------
Bob Follett AB7ST, QRP-L # 129, NorCal, ARCI, 10-10, ARS
2861 Estates Dr. VOICE: 801.649.6457
Park City, UT 84060 E-mail: bfollett@ditell.com
nnnn
36. Subject: Re: SST Tuning Range
From: "Paul Christensen"
Date: Sun, 22 Jun 1997 18:07:36 -0400
Ken:
It's the mod suggested by Wayne in the SST's manual: use a SPDT switch
to switch between the two supplied varactor diodes.
-Paul, W9AC
37. Subject: SST not a toy!/SST mods summarized...
From: pmeier
Date: Sun, 29 Jun 97 11:19:11 -0400
Although the SST is a lot of fun to build and operate, I have come to
the conclusion it is not a toy but a very decent rig. I used it for a
few hours yesterday during field while enjoying the beautiful weather in
a local park here in Michigan.
To preface the next statement let me state that I don't compete
seriously during the June Field Day ( I save that for the Sept. QRP to
the Field :). I go out to a local park and operate for just a few hour
to enjoy the outdoors and have some radio fun. But to my point here...
The SST is a wonderful radio which is very well designed and thought
out. I say this after spending Friday evening building it and then
taking it out to yesterday's FD event. I made 7 contacts in the first
hour on 20 meters with just about 2 watts into an SLV! This may not
sound outstanding but considering the low power, the ease in which I
made contacts in the crowded frey and in
with relatively small 10khz of tuning space I WAS IMPRESSED!
Tuning is smooth as is the keying with no THUMPS! The audio is plenty
loud with a very nice tone. As reported in Chuck's early review the unit
went together easily and quickly. I found only one minor mistake and
that was the value given for the choke RFC5 on the schematic. It was
listed as 15uh but is closer to about 34uh. Follow the parts list and
use 10 turns for RFC5. I incorporated the mods posted here on the list
and found them all to be useful. I replaced C10 with a variable trimmer
(8-60pf). I installed the VBX mod but found I kept it about mid way
through its range. I followed Dave Meacham's mods for using a 15K
resistor across the pads of the tuning pot (for tuning linearity) and
replaced the 6.8 choke at RFC3 with a 5.6uh unit to bring the top of the
range up from 14058 to 14062. This mod reduced bandwith from 20khz to
10khz however. But then again, I mostly look for QRPers and this allows
plenty of range for "us".
I also added a KC1 keyer which installed easily and worked flawlessly
(just follow Wayne's directions in the SST manual).
All in all this is a great rig that is very small and very easy to build
and for well under a hundred bucks. In my opinion it's not a toy but
another of WAYNE'S WONDERS.
Pete WK8S
38. Subject: W6EMD mods summary
From: "David D. Meacham"
Date: ??
Gang,
Since I posted the tuning mod on June 18, someone commented that 18k was
a better resistor value. I just got around to trying it. It IS better,
in fact, it is optimum, according to my measurements. Higher values
don't do any good, while lower values give poorer linearity. At 18k,
with dial full counter-clockwise I get 14.054, straight up I get 14.059,
and full clockwise I get 14.063. So the first half of the dial covers
5kHz, while the secondhalf covers 4kHz. Not too shabby!
In case you missed the first posting, the resistor goes across two of
the terminals of the tuning pot (from the wiper to the 8V side). I use
the MV-209 varactor, and a 5.6uH choke (Mouser # 43LS566) for RFC3.
Enjoy!
72, Dave, W6EMD
nnnn
39. Subject: LM386
From: lve1@inel.gov (Larry V East)
Date: Fri, 28 Feb 1997 16:57:36 -0700
Paul -- I just read "The LM386 Cookbook" by you in the latest "Low
Down". Lots of good information there, but I was a bit amazed that you
failed to mention the use of a bypass cap on pin 7. A small electrolytic
or tantalum cap of a few uF from pin 7 to ground will isolate the high
gain input stage of the LM386 from power supply noise, hum, transients,
etc. Such a bypass cap is much more effective in this regard than the
"brute force" Vcc filter that you recommend in your note #2.
You aren't the only one to ignore this; most commercial rigs (and kits)
using the LM386 either fail to bypass pin 7 at all or use too small a
value (0.01uF or 0.1uF) to be totally effective. For example, Index labs
uses a value of 0.1uF in their QRP PLUS and increasing the value to
4.7uF completely eliminates the "thumps" in the audio output produced by
Vcc transients when the transmitter is keyed.
I don't mean to be critical, but I just don't understand why the proper
use of the LM386 "bypass pin" seems to be overlooked by almost everyone
(in "hamdom", at least) using this device! It's even label "bypass" in
the data books (and your Fig. 2 in your "cookbook" as well).
72, Larry W1HUE/7
40. Subject: Re: LM386
From: gsurrency@juno.com (Gary L Surrency)
Date: Fri, 28 Feb 1997 22:39:06 EST
Amen, Larry! The LM386 data sheet shows up to a 50db Power
Supply Rejection Ratio (PSRR) with a 10uf cap from pin 7 to
ground and the gain at 20 with 6V supply and 1 khz operation.
My Ark30 had a squirrley sounding low level noise before I put a
10uf tantalum on pin 7 to ground. It might have been coming from
some of the digital synthesis circuitry and was most noticeable
when using headphones.
One glance at the LM386's internal equivalent schematic shows
why this decoupling cap is so needed. Pin 7 is right on the chip's
bias network.
BTW, on the ARK30, I placed the 10uf tantalum cap on the foil
side of the transceiver board. It just fits between the PCB and
the shield plate.
I have also found on many op amp circuit designs, that the unused
input pin ALWAYS need to be decoupled if it is not grounded or you
will invariably get keying or T/R thumps in the audio chain. Several
radios I have or have looked at omit this decoupling cap on the
resistive divider on the non-inverting input (+ lead). The TAC-1 had
this problem on the op amp following the CMOS bilateral switch chip.
A 0.33 uf monolythic axial cap fixed it completely, and killed the
thump.
Bypass that lil sucker!
72,
Gary Surrency AB7MY
S&S TAC-1(40&80m) and ARK30, AT-11 (QRO and QRP)
QRP-L #571 Chandler, AZ (near Phoenix)Grid Square DM43BH
Az ScQRPions
nnnn
41. Subject: Re: SST-20 mods query from AL7FS
Date: Sat, 2 Aug 1997 18:27:49 -0700 (PDT)
From: Alan Kaul
CC:
"David D. Meacham"
Hi Jim ... my mods are simple ... Dave, W6EMD's are a little harder.
Mine involves the VXO --- add a second 18mHz xtal in parallel (solder it
on bottom of board across the first 18mHz rock), then change the VXO
inductance to around 4uH. I have not yet experimented with a high Q
coil, but I think using a toroid with parallel xtals would increase the
tuning range a bit more. My molded choke coil is low Q and from Mouser
(nominal value approx 3.8uH). VXO range is 14047-14063 using the MV 108
diode. I'm not finished yet -- I plan to experiment a little more.
Dave's mods are a little more complex -- his e-mail address is:
ddm@datatamers.com
and you might ask him about them....I don't want to steal his thunder,
he's told me he's writing a piece for the next issue of QRPp.
GL and report back on your results! 73/72 de alan
[] kaul@netcom.com
42. Subject: SST 2 diodes mod.
Date: Wed, 2 Jul 1997 11:29:12 -0600 (MDT)
From: bcutter@teal.csn.net (Bob Cutter)
I just finished my SST(20M) with the two diodes and a SPDT switch. I
really
like the bandspread this gives and would encourage anyone to give it a
try.
As the bands improve it is going to get crowded around those calling
frequencies and we need to spread out a bit.
72, Bob KI0G
43. Subject: Re: SSTs
Date: Wed, 2 Jul 1997 13:54:55 -0500
From: wmcshan@REX.RE.ouhsc.edu (Mike McShan)
>John,
(snip)
>reciever. Maybe the problem is your headphones. Have you tried a different
>pair? 72, Dave, W6EMD
I have to agree with Dave. Changing headphones can make a big
difference.
On my NC38s, the audio is mediocre with a pair of Sony stereo phones.
However, switching to a similar pair from Radio Shack (Nova 43) results
in
a dramatic increase in volume (often to the point of uncomfortable).
Mike N5JKY
Edmond, OK
44. Subject: SST Varactor Switching
Date: Thu, 3 Jul 1997 12:32:03 -0800
From: "walter.b.thomas.1@pop300.gsfc.nasa.gov"
For those folks using a switch to change between
the MVAM108 and MV209 diodes in the SST VXO, consider
using a subminiature DPDT switch. Use one pole to
switch the diodes and the other pole to switch the
resistors used to make the "dial" more linear. The
linearizing resistors will be different for the two
diodes. This worked great on my SST40.
Dave W6EMD found 18K to work best for the MV209 on his
20M SST. I used a 3K0 resistor for the MVAM108 on my
SST40. Your mileage may vary, so you may have to
experiment with the resistor values.
73 Walt WA4KAC
45. Subject: SST VXO Problem
Date: Fri, 04 Jul 1997 22:27:52 EDT
From: kk5py@juno.com (dennis l foster)
Hello to all and hope this makes it to the list as it is my first try!
I
built my SST the day it arrived and it worked as advertised except for
one problem that I have sort-of solved. I used the D4A diode and found
that at the top of the tuning range the VXO shuts down. I noticed that
I
could push RFC-3 away from X6 with what little movement it had, and the
VXO would work again. I can also just touch X6 and it shuts everything
down until I tune to the lower part of the band spread and it starts up
again. I have temporarily solved the problem by moving the RFC-3 to the
bottom on the board. Touching X6 still shuts everything down but it
recovers as soon as I remove finger! Has anyone else had this problem
and what might be the cause and the correct solution? I think using a
lower value choke in place of RFC-3 would be the remedy but not sure! I
just don't like having to move parts around to get things to work right.
Any and all input would be received graciously! Also, has anyone
successfully integrated the Tick Keyer into the circuit so Tick audio is
available at the headphones?
Dennis Foster
KK5PY
46. Subject: Re: SST & TiCK
Date: Sat, 5 Jul 1997 06:51:06 -0400
From: "Paul Christensen"
Dennis:
Here are two reposts of my previous messages:
I went out on a limb and tried something I hadn't done before.
Since the TiCK is rated between three and five volts, and the SST's
regulated voltage is eight volts, some form of voltage drop is required.
While it's possible to use the TiCK's 78L05 regulator (supplied with the
DIP-style kit), I chose to use two LEDs in series between the SST's
eight
volt supply and the TiCK. I'm not sure what, if any additonal current
is
spared by not using the additonal regulator, but it was an interesting
experiment nevertheless. If I get a chance, I'll measure current
consumption with both configurations. Until then, I plan on leaving it
this way in mine.
-Paul, W9AC
Like the Like the Wilderness KC1, the Embedded Research TiCK has the
ability
to inject sidetone audio into a transceiver. While I generally like to
keep the sidetone off and let the rig provide it's own sidetown when
available, it's still necessary to couple this audio into the rig for
programming puposes. Embedded's Piezo alternative just doesn't cut it
for
me.
The TiCK manual states a value of a 1Meg resistor for R3 for use with
the
Norcal 40A. The results in a very low sidetone audio level on the SST.
Simply change R3 to 100K to form a more proportional voltage divider.
To
my ears, this value provides a sidetone level that's "just right." As
an
alternative, one could replace the TiCK's R2/R3 voltage divider with a
100K
micro-potentiometer. then you'll have the ability to set the level
anywhere you want it.
-Paul, W9AC
47. Subject: "Choking" the SST
Date: Tue, 8 Jul 1997 20:49:11 -0700
From: talljazz@teleport.com (Dan Presley)
I couldn't locate (locally) a 5.6uH choke for my 20M SST, to replace the
6.5 choke in the VXO circuit. I did find a 4.7, so was wondering if I
can
wind a few turns on it to get it up around 5.6. Anyone have a 'formula',
or
suggestions? Also, this is a smaller molded choke than supplied w/
kit-any
problems? Thanks!
Dan N7CQR
48. Subject: Re: SST Tuning Mod revisited
Date: Fri, 11 Jul 1997 02:14:32 -0700 (PDT)
From: Alan Kaul
Hi Gang .... got home from my trip to Northern California to find
my 20M SST waiting (Bob shipped it priority mail -- it beat me back from
the
Norcal Meeting!!!!). I know Dave Meacham has made a pretty good linear
tuning mod by soldering an 18k resistor from the tuning pot to the 8V
regulator. I've still got his post. And I read where someone else
changed
C10 to 15pf AND R10 to 120 Ohms -- but I don't know if that was on the
20M
version. If anyone has any mods for the 20 Meter SST, I'd love to hear
about them before I plug in the solder iron!!
Pls and tnx and best 73/72 de alan
[] kaul@netcom.com
49. Subject: The HB Sprint and the SST
Date: Fri, 11 Jul 1997 03:44:57 utc
From: k7sz@juno.com (Richard H. Arland)
Gang:
Had the 20 meter SST on the bands this evening for the HB sprint. What
follows are a few observations.
1. The tuning on my SST is 30 kc with the MV-201 and 50 kc with the
MVAV-108. Unfortunately the latter does not offer coverage in the QRP
section of the band, as it stops at 14052.5 khz. Therefore I opted to
use
the narrower tuning range offered by the MV-201 varactor.
2. The stock IF BW is way too narrow. I performed the mod as outlined in
the manual and it is still too narrow for my liking. I;ll have to do
some
cap substitutions and see what I can come up with.
3. Even with the wider IF BW (after the mod) tuning was still much too
critical. There is no room for a vernier drive so out came the box of
knobs and a spare NC-40A main tuning knob was stuck on the front of my
SST. It looks a little wierd, but it does a much better job of tuning in
stations.
4. This is a Minimalist's radio. Therefore, it is designed to be used
when camping, hiking, ect, NOT in a normal hamshack. The controls are
somewhat crowded and I find that this is not a pleasurable rig to
operate
like the Sierra of the NC-40A.
5. Performance is fantastic considering that it has about 1/2 the parts
of a NC-40A and is about 1/3 the size. Wayne Burdick did one hell of a
job designing this rig. Power output with a 13.8 volt DC supply was 2.25
watts. On a 12 volt Gel-Cell power drops off to just under 2 watts.
Receive sensitivity is very good and selectivity (of the stock radio) is
so good, you often tune right past stations unless you tune R-E-A-L
S-L-O-W.
I have not tried this radio into a less-than-optimal antenna, and I
suspect, upon reading the manual, that performance will suffer
drastically if the antenna is not exactly 50 ohms at the operating
frequency. End of the month, I'll be testing this theory on the Flight
of
the Bumblebees from Lake Wallenpaupak.
73 rich K7SZ
50. Subject: SST-Internal Batteries
Date: Sun, 13 Jul 97 18:49:47 +0000
From: tgordish@concentric.net
QRP Folk,
Well after starting a never ending thread on Renewal Batterys, I was
discouraged from using them do to the problem with charging them while
in
the rig. I opted for little cordless phone batterys available from
Radio
Shack. I bought 2 packs of 3 cells and one pack of 4 cells and soldered
them all together. They fit nicely into the SST and give 12v. Total
rig
weight with batteries is only 11.5 oz. Then I hooked up to the switch
and made a solder bridge accross the power switch contacts so that I
could charge the batteries while hooked up to external power and the
switch set in the BATT position. Checked it out and seems to be working
fine. Tried a couple of CQ's but no one was out there. Now a couple of
questions:
1. These batteries are rated at 250mah, will this amount of power get
me
through a 2 hour Spartan Sprint or do I need to crank the power down a
bit?
2. What would make a good charging voltage for these 10 little
ni-cads?
Is it 13.8v like I use with my gel-cell?
Look out you Spartan Sprinters! (I hope I don't regret divulging the
secrets of my set up!) I won't be able to run the August Sprint, but
will
be bringing the rig with me while I serve my annual 35 Navy reserve days
at Great Lakes Naval Station.
72 de
Tim & Aretta Gordish
KB9LGJ & N0YDG
Yuma, AZ
51. Subject: "Potential" Super SST
Date: Fri, 22 Aug 1997 16:53:54 -0400 (EDT)
From: Chris Cartwright
Gang,
I now have an SST for every band (except/N), no I don't want to part
with
any:) However, I got a 20M unit from Rich, K7SZ and it tunes ~14.002-052
or 14.036-065 depending on the varactor. This seems *abnormally* wide
and I'd like to find out why, and pass it on to other SST owners. (and
expand coverage on my other two) And yes it's very non-linear, the
"bottom" of the dial is *very* crowded.
I have a fair compliment of test equipment but ne
52. Subject: Re: "Potential" Super SST
Date: Fri, 22 Aug 1997 15:17:18 -0700 (PDT)
From: "David D. Meacham"
Chris,
Why not find out what K7SZ did to it? BTW, my 20m SST xtal says:
ECS H
18.00-20
CHINA K5
It gives a range of 14.054-14.063 with the MV209 Varactor and 5.6uH for
RFC3.
72, Dave, W6EMD
53. Subject: Re: SST - working (replace the PA with an MRF 237)
Date: Wed, 27 Aug 1997 16:29:31 -0700 (PDT)
From: Kory Hamzeh
I was able to get 3 watts easily with a 12 volt supply. The replace the
PA
with an MRF 237 (e & c are backwards), took one turn of off L2, and used
110 ohms for r10. I haven't checked to see how much about I can put out
at
13.8v yet.
Kory
AC6RN
54. Subject: SST for WWV 10.000 Mhz
Date: Sat, 06 Sep 1997 20:39:37 EDT
From: n4so@juno.com (charles k brown)
The SST for 30 meters can be modified to receive WWV
on 10.000 Mhz.
I have a mod file that has some suggestions for
doing this which are by the designer.
The text file is on this computer-- ask for WWV.txt.
from: n4so@juno.com
Ken Brown, N4SO
QTH nr Mobile, AL/ EM50tk
qrp-l #622
n4so@juno.com
55. Subject: Subject: [27051] Re: SST/40 question
Date: Mon, 22 Sep 97 09:12:03 -0400
From: cjl@mail09.mitre.org (Charles J. Ludinsky)
Frank, G3YCC, writes:
> In message <199709172335.TAA47088@nss2.CC.Lehigh.EDU>, Joel Malman
> writes
>
>> 2. The SST seems to drift a bit more than I expected. Did anyone else
>> notice this?
>>
> I am surprised at that. Unless you have extended the tuning range
> greatly, there should be no problem.
> Have fun!
If the power supply is not quite "solid", some frequency drift will
occur. For
example, alkaline batteries (e.g., AAs) will drop sufficiently in
voltage
during use to cause the output from the internal voltage regulator to
change by
some 10s, or even 100s, of millivolts. This is more than enough to
cause
annoying drift and chirps.
72 de Chuck, K1CL
56. Subject: Simple Superhet Transceiver SST
Date: Fri, 26 Sep 1997 12:01:02 -0800
http://www.fix.net/~jparker/wilderness/sst.htm
Wilderness Radio
P.O. Box 734
Los Altos, CA 94023-0734
(415) 494-3806
CREDIT CARDS NOT ACCEPTED
The Simple Superhet Transceiver
SST
The SST is an optimized, superhet rig with an extremely low parts count
(only 80 parts, vs. 100 for a
38-special and 120 for a NorCal 40A).
This may be the easiest to build superhet ever, and it comes with a
miniature custom enclosure, less than
half the size of a NorCal 40A.
SST Features:
- 2 watts out (varies w/band and supply voltage), adjustable down to
zero
- fast, clean QSK with transmit monitoring
- 3-pole crystal filter at a low I.F. (about 4 MHz)
- built-in, no-adjustments AGC with received signal indicator LED
- stable VXO coverage of 10 to 20 kHz using varactor tuning (range
varies w/band)
- very low current drain--about 15mA
- stable operation from 10 to 16VDC, or internal 9V lithium battery
- works with the Wilderness KC1 keyer/ counter and BuzzNot noise
blanker.
- both the KC1 and BuzzNot can be installed inside the SST
- all controls, connectors, and parts mount on a single 3.0" x 3.4"
PC board
- 1.5"H x 3.2"W x 3.5"D custom enclosure (supplied unfinished)
RECEIVER:
A superhet with a sharp, three-crystal filter, operating at a low I.F.
(around 4MHz). The receiver uses a
novel AGC circuit employing a single LED as both the detector and signal
indicator. The AF gain control
and headphone jack are on the front panel. The RF gain is rarely used in
the SST, so I put it on the back.
TRANSMITTER:
The Transmitter has *really* fast, exceptionally clean (totally
thump-free) QSK with TX monitoring, as
in the '40A. Power output is around 2 watts on all three bands with a
13.8V supply, and proportionally less
at 12V or 9V. Power out is adjustable down to zero.
Varactor-controlled VXO rather than a VFO with excellent stability.
Frequency coverage (approximate):
40m 7.032 - 7.042
40m/novice 7.105 - 7.115
30m 10.105 - 10.120
20m 14.046 - 14.064
VXO range can be increased by switching in a second varactor. All VXO
and I.F. crystals used are
*standard* frequencies available from Digikey.
The custom enclosure is about 3W x 3.5D x 1.5H", and is supplied
unfinished. Since the box is so small,
we use .050 aluminum to reduce weight. (With a KC1 on the top and an
internal 9V lithium battery, the
SST makes a great TFR.
PRICE AND KIT INFO:
The SST is supplied only as a complete kit -- no partials.
The kit includes a high-quality double-sided and silkscreened PC board;
a custom, unfinished .050
aluminum enclosure with hardware; all controls, connectors, knobs,
rubber feet, etc.; detailed manual;
and all parts for your choice of bands.
The price for each complete SST is $85.
ORDERING INSTRUCTIONS
1. Please enclose $85 per kit ordered.
2. For each kit ordered, you must specify the band: 40m, 40m/novice,
30m, or 20m. (Remember, this is a
VXO-based transceiver, so the rig does not cover the entire CW band.
Approximate coverage is: 40m,
7.032-7.042; 40m/novice: 7.105 - 7.115; 30m, 10.105-10.120; 20m,
14.046-14.064. Other ranges are
possible with small modifications.)
3. California residents must add 7.75% sales tax.
4. Shipping charges are extra: $3 U.S., $5 Canada/Mexico, $15 DX
(other). This is a per-kit shipping
charge.
5. Please make out checks to Wilderness Radio. We'll also need your
name, call, address, phone number,
e-mail address.
6. Send U.S. funds only (checks drawn on US banks, or an international
money order) to:
Wilderness Radio
P.O. Box 734
Los Altos, California 94023-0734, USA
For more information, call Bob at:
(415) 494-3806
CREDIT CARDS NOT ACCEPTED
57. Subject: SST/20 Question
Date: Sun, 5 Oct 97 19:21:53 EDT
From: Joel Malman
Group,
I finished building an SST for 20 meters today. It seems to work fine..
(first QSO: PA0IJM). Problem: every time I power the SST on, and the AF
gain and RF gain happen to be ALL the way up I get this very (*VERY*)
loud
blast of noise.
If I power the SST on, at any other AF or RF gain setting, the rig is
fine .. no loud blast.
Anyone have a clue??
thanks,
/joel wa1qvm
58. Subject: SST-40
Date: Mon, 06 Oct 1997 23:21:26 EDT
From: kc4mhm@juno.com (ed miller)
Gang:
Got the new SST-40 on the air this P.M.
Heard AR station calling CQ and he answered me on my first response. He
was QRO so I had good copy on him, he gave me a 599 for my 2 watts. Who
could ask for any more?
Had to change C10 to 22pf to increase side tone to where I like it.
Tunning range is 7.030 to 7.039. Would rather have 7.035 to 7.043, will
work on that later. Hope the fox is below 7.040 tomorrow nite.
See ya'll tomorrow; Tally Ho.
73 de Ed
KC4MHM@juno.com
59. Subject: sst (Oct 1996 Info from Wayne Burdick)
Date: Sun, 20 Oct 1996 21:27:45 -0800
SST Progress Report #2: built-in keyer option (the
"KC0")
L.Svec,W.Burdick (svecbrdk@well.com)
Thu, 17 Oct 1996 23:42:51 -0800
Messages sorted by: [ date ][ thread ][ subject ][ author ]
Next message: Nick Franco: "NHTF and Coming FoxHunt"
Previous message: Nick Franco: "Re: FOX Novice Mortified!"
For those interested in upcoming SST kit:
I thought I'd give you a little more detail on the promised SST keyer
option, as well as a couple of other SST notes. The SST is so compact
that
I had to plan ahead for where the keyer, speed control and paddle jack
will
go.
By the way: I'm doing the KC0 on my own at this point--it isn't clear
whether I or NorCal will supply it. Also, it is intended just for the
SSTs--it is not a new "product." The KC0 name is just a reminder of its
ancestry. More on that in a minute.
Someone mentioned the pending availability of a keyer based on the new
PIC
12XXX series 8-pin SOIC microprocessor. For those who don't know, SOIC
=
small-outline IC = SURFACE MOUNT. Thank you, in advance, for providing
the
world's smallest keyer, and congratulations for being first to announce
a
ham product based on the new PIC 12XXX series.
The SST keyer uses the same chip, except it's the through-hole version
(i.e., it has 8 leads--same form factor as an NE602AN or LM386N). In my
experience SOIC parts are hard to see, much less solder, so I'm glad
someone else is doing the dirty work. In fact, I'll bet Jeff Anderson
(of
40-9er-in-a-9V-battery-can fame) can't wait to get his hands on one! On
the other hand, if consumer electronics conspires to make through-hole
parts go away, noone over 25 will be able to build kits anymore. ;(
KC0 Features
Back to the KC0: I'm porting the KC1 code to it, less the frequency
counter, which isn't needed on the SST since the dial only covers 20 or
30kHz and it will be calibrated by the user. There's also no message
memory, since the PIC 12XXX parts don't have any EEPROM (yet). When
they
do, probably in 1997, the KC0 will get retrofitted with message memory.
The KC0 includes an input pin that lets you choose between two Iambic
keying emulations, just like the KC1: Curtis mode "A" and Super CMOS
mode
"B". The latter is similar to Curtis mode B except the timing is easier
to
use (thanks again to Bob Finch for pointing this out!). Ya know, I
still
think mode B started off as firmware accident, perhaps on a night when
the
lighting was bad and there was a pet Iguana on the keyboard. :) But
then,
I learned on an old 8044 with mode "A", so I may be a distant relative
of
the Iguana. But there it is--mode B if you want it.
The KC0 will come with a VERY small PC board (< 1" square) that has the
micro, 1/8" paddle jack, and the speed control (a small pot, not a
button). This board will plug right into the SST board using only 3
wires,
and it will mount to the rear panel with holes provided. The keyer jack
holds it to the panel and the speed pot's shaft acts like a stop to the
board from spinning around :)
Other SST News
I'm getting closer to nailing down the custom enclosure size, for those
who
want one. It will be 2.5" wide and 4.5" deep, and just about 1.3" tall.
The 9V lithium battery fits inside, and uses 9V battery clips on the PC
board itself--no more floppy 9V battery connector with wires! In fact,
except for the pots and some happy electrons, the SST is a no-moving
parts
radio :)
Note on the SST's audio output: it WILL drive a speaker, unlike the
40-9er, although I'll still recommend headphones for minimum distortion.
73,
Wayne
N6KR
60. Subject: SST 20 mods, thoughts...
Date: Thu, 9 Oct 1997 16:37:22 +0100
From: Frank G3YCC
I must say I am delighted with the SST (20m) rig, but just pondering
some ideas for mods:
1 It could do with a bit more on the Rx side. Wondering whether to
add a dual gate MOSFET preamp or perhaps a balanced 741 audio preamp.
2 VFO thoughts - I obtained a 16mhz xtl and thought that instead
of the VXO, a NE601 (or 612) mixer/osc using the 16mhz and mixing with
that a 2mhz VFO, which should be pretty stable at that low freq. A
simple tuned cct would clean the o/p up and perhaps a small rf amp to
boost the o/p. This could be built in or external. The VXO could be
either left in and switched off if the VFO is used, but would be there
for compactness if required. If the VXO is not needed, it could be
modded as the VFO on 2mhz +/-.
3 The RF gain on the back is never used here, so, I could use that
as a speed control for a built in keyer...
4 The pwr switch on the back also is redundant in my case, so it
could be used to either switch the VXO on/off and activate the VFO
(above).
With the standard varicap mine tunes 14.046 - 14.056 about. Funny thing
is though, with the tuning pot at either end of it's travel, the VXO
stops working, any ideas?
The output is exactly one watt on the d/load-pwr meter.
--
Frank G3YCC GQRP 042
QRP Web Page: http://www.g3ycc.karoo.net/
Packet: G3YCC@GB7HUL.#15.GBR.EU
61. Subject: Re: SST 20 VXO range
Date: Fri, 10 Oct 1997 14:30:35 -0400 (EDT)
From: G3TUX@aol.com
Hallo Frank!
I still have not got around to building my SST/20 - but my pal, Hanns
DK9NL, has completed his. He replaced D4 with a BB205B and now tunes from 14041
to 14063. Hope this info is helpful.
I have downloaded the SST mod. file from your web site - many thanks.
Hope to see you at Rochdale. 73 Chris G3TUX
62. Subject: sst 40M audio problems-howl (See Number 68)
Date: Sun, 12 Oct 1997 10:45:22 -0400 (EDT)
From: PULLJIM@aol.com
HELP ! My 40M SST has a howl or some kind of tone on receive. It draws
17.5M.
Parts are placed correctly, and there are no solder bridges.
I have tried several different head phones, all have the same results.
The howl is clearly heard even with the volume turned down. As volume is
increased the howl is louder, and it draws 22M. Anyone have any ideas ?
63. Subject: Re: SST Mods URL
Date: Sun, 19 Oct 1997 17:09:00 -0700 (PDT)
From: "David D. Meacham"
Frank,
The Fall issue of NorCal QRPp has my SST mods article on page 10. (W6EMT
is listed on the cover as the author, by mistake. It should be W6EMD.)
It's not a web site, but it has several mods!
I understand that the mags will be shipped within the next two weeks.
72, Dave, W6EMD
64. Subject: Re: SST: Greatly improved VXO Range (thanks, N6GA!)
Date: Thu, 23 Oct 1997 23:37:35 -0700 (PDT)
From: Alan Kaul
Hi Wayne ... I did the same thing as CAM and have about 18kHz tuning.
Article describing ''super VXO'' written by a JA and posted to this list
about a year ago, but the Japanese version uses a higher Q coil (slug
tuned from about 4uH to 7uH) according tov the post. I still have a
copy of the original if anyone is interested.
There's another version on one of the 7L-amateur websites (also have it
bookmarked somewhere) and he also uses a shunt resistor of about 10K
across the coil.... let me know if anyone wants to see either.
73/72 de alan, w6rcl
65. Subject: SST: Greatly improved VXO Range (thanks, N6GA!)
Date: Thu, 23 Oct 1997 23:01:47 -0800
From: svecbrdk@well.com (L.Svec,W.Burdick)
Hi all,
Hope this hasn't already been posted--if it has, I missed it.
At Pacificon, Cam Hartford (N6GA) showed me his 20 meter SST with a neat
twist: over twice the usual VXO range! How did he do it? By simply
paralleling a *second* VXO crystal of the same frequency across the
first.
Cam said he got the idea from an article, but I didn't catch where or
when it was published. The basic idea is that the second crystal lowers the
circuit Q. Perhaps Cam will fill us in on more details.
In addition to adding the crystal, he had to reduce the size of the
series RF choke to keep the range from being too large (!). At some point that
tiny pot is too small to tune signals in.
I'm hoping to convince some of you SST owners to try this on your own
SST. Since all of the VXO crystals used are standard microprocessor
frequencies available from Digikey, you shouldn't have trouble getting a "sample"
(wink, wink) of one or two crystals from them.
If you try this experiment, please let me know, whether you do it on the
SST or any other rig. Since I'm revising the SST manual for the next
run, I'd like to include as much information as possible about modifications
that increase the rig's performance.
Have fun!
73,
Wayne
66. Subject: SST VXO Range (Thanks W6RCL!)
Date: Sun, 26 Oct 1997 07:30:15 -0800 (PST)
From: camqrp@cyberg8t.com (Cam Hartford)
Gang -
Sorry for being slow on the draw here, but sometimes the digests just
pile up. It was Alan Kaul, W6RCL, who gave me the idea for using the Japanese
wide-Range VXO in the SST.
In stock form, my 20 meter SST tuned about 16 KHz. Alan sent me one of
the postings from QRP-L that he had collected on the subject of the wide
range VXO, so I thought I'd give it a try.
I sent off to Mouser for a couple 18 MHz crystals and several small
molded chokes like the ones used in the SST. I got a variety of small values so
I could use them singly and in series to get small steps from 1 to 10 uH.
At this point I'll leave out lots of gory details about hundreds of
different crystal/inductor combinations except to say that with the two
Mouser crystals in parallel and the original 6.8 uH inductor in the
circuit, the tuning range was about 70 KHz! This was way too much range for a
one-turn pot, and the thing was drifty.
Wilderness was kind enough to send along two different varactors with
the kit, an MVAM108 and an MV209, so we could choose different frequency
ranges. I ended up using both. My rig is now configured like this - 1) A toggle
switch on the front panel to chose between the two varactors; 2) two of
the Mouser crystals in parallel (one in the original X6 board location, the
second one tacked soldered on the bottom of the board parallel to the
first); and 3) the final value of RFC 3 is 4.8 uH.
This configuration gives the following frequency coverage range - Lo
position, 14.026 to 14.058, and Hi position, 14.056 to 14.070. I could
have gone with a little more inductance and covered 14.000 to 14.070, but
this is a bit much for only two turns of the tuning pot. As an example, a 5.6 uH
inductor gave tuning ranges of 13.982 to 14.047 and 14.039 to 14.065,
respectively.
The downside is that it does drift more than a normally configured VXO.
I haven't done extensive drift tests, but a quick check reveals the
following: in the Lo position, which pulls the crystals farther from their design
frequency, it drifts about 200 Hz in the first twenty minutes, but is
fairly stable from then on. The High position, which covers frequencies much
nearer the crystal frequency, shows only about 60 Hz drift from startup.
All of which suggests that the range can be extended quite a bit by
using two parallel crystals. The tradeoffs are increased drift, along with a
greater range to be handled by a one-turn pot. Miniature ten-turn pots,
anyone?
72/73,
Cam N6Ga
67. Subject: SST XCVR SURVEY: your input needed for next release
Date: Wed, 19 Nov 1997 09:14:15 -0800
From: "L.Svec,W.Burdick"
Hi gang,
The SST has passed its field-test, and will now become a permanent part
of the Wilderness Radio product line. I'll be making a number of minor
adjustments to the PC board, enclosure, and circuitry, based largely on
comments sent to me by INET and NorCal QRP club members. Thanks again
for your help!
While I think I've got everything nailed, I wanted to get one more round
of input from those of you who modified the SST circuit in some way, either
to fix a problem or to add new features. Even if you have only duplicated
someone else's modification, I'd like to hear from you. Please send
your answers to the questions below directly to me at svecbrdk@well.com. No
need to copy them to QRP-L unless they are relevant to the entire group
(which I imagine has by now heard plenty of SST stories :)
The revised SST will be available after Jan 1, 1998, and the price is
$85. As before, it will be offered for 40, 40/novice, 30, and 20 meters. If
you'd like more SST information or a Wilderness Radio catalog, please
call Bob Dyer, KD6VIO at 650-494-3806, or send him e-mail at:
qrpbob@datatamers.com.
72,
Wayne, N6KR
* * *
1. Did you build any accessories into your SST, such as a
KC1, Buzznot, etc.? If so, please describe any modifications
that were needed, how well it worked, etc.
2. Describe any modifications that you made to the SST's VXO:
3. Which varactor diode did you use?
___MV209 ___MVAM108 ___BOTH
4. What is your VXO frequency range?
(List two ranges if you used both varactor diodes)
5. Describe any modifications that you made to the receiver:
6. Describe any modifications that you made to the transmitter:
7. Please list any other changes that you'd like to see made
to the SST in the future:
68. Subject: SST Coyote Killer -- One Easy Step
Date: Mon, 24 Nov 1997 20:59:36 -0800
From: "L.Svec,W.Burdick"
A long, long time ago (well, about five months) someone on the list
suggested that the cure for the SST's "howl" problem was to put an
electrolytic cap between pin 7 of the LM386 and ground. He was right!
Normally you don't need a cap here if you run the '386 from a regulated
supply, which is why I left it out. But it turns out that the LED-based
AGC circuit I'm using creates enough of a feedback loop that in some
cases it causes trouble. The pin 7 bypass cleans it up.
Other suggested solutions took two or more parts, so this single cap
method was the one I preferred. After all, I'm genetically programmed to try
to keep parts count low :) and there ain't much room left on the SST's PC
board.
I never could duplicate the problem at my QTH, so I enlisted the help of
several SST owners to try this, and the results are in: we're
three-for-three. Even 1uF will do it, but I already use a 2.2uF cap
elsewhere in the rig, so 2.2 it is. Safety margin doesn't hurt.
So, if you still have a coyote in SST's clothing, kill that critter now
with a "2.2" gauge. You can use any cap with a 10V or higher rating.
The smaller ones will actually fit on the bottom of the PCB.
Once again the INET troops have come through--thanks!
72,
Wayne
69. Subject: Expanded SST Freq Coverage
Date: Fri, 28 Nov 1997 18:14:05 -0700
From: Steve Galchutt
I just tried strapping another 18 MHz rock accoss the other one in my
20m SST and I couldn't believe my eyes the the counter said 14,004 to
14,057! WOW...that almost 50KHz hmmmm... now if I can just move it up to
above 14,060! Tunning is a little rapid. Maybe a 10 turn pot would
solve this? But my counter just died @#$*&! ....well time for something
else...like XC skiing. We just got about 15" of new white stuff last
night here in Colorado. sush....sush....sush
--
CUL Steve/n0tu . .
Solar powered QRP/CW
Monument, CO..........email:N0TU@webaccess.net
70. Subject: SST problem
Date: Sun, 14 Dec 1997 19:52:20 -0500 (EST)
From: Chris Cartwright
Just wondering what the most common parts for failure are on an SST that
had been hooked up to a 7AH gel cell backwards. I'm asking for a
friend, really, yeah that's it... I... err... He knows the RFC in the final
is burnt open, the zener and final don't look to healthy, but there is also
no RX. The KC1 seem to function, but is confused, and audio from the
SST (from the KC1) is very weak.
I've told him he should put a fuse and diode in the power jack. I'll
make sure he does when *I* "help" him fix it. 72 es tnx
All kidding aside, I did smoke it, and have and unbuilt 40M SST so I
have "spares" of almost everthing. If no one have been through this before
I'll post the casualty list when I get it back together, and it will
have a fuse and diode this time :) I would like to get the list down to
individual parts instead of "shotgunning" it to get it going. I have
the schematic out now... making a list and checking it twice.
-- Chris Cartwright, Technical Engineer |
ccart@vidtel.com --
-- N3XRV ARRL-VE QRP WAS 27/10(w/c) |
http://dns.vidtel.com/~ccart --
-- QRP-L #655 NORCAL #1891 QRP-ARCI #???? NJ-QRP #105 LIQRP
#???? --
71. Subject: Re: SST problem
Date: Mon, 15 Dec 1997 00:18:41 -0500 (EST)
From: Chris Cartwright big 'ol giant grin> I got a nice note
from NA5N recanting how he killed Dougs SST :) He was right on all counts,
Zener, choke and trace fried.
It took five parts, and all of them were "in stock". The 15uH choke in
the final had been vaporized so I rewound the toroid, and measured it
(six turns instead of ten just like last time). The zener in the output
circut seemed to take the brunt of things. It looked OK from the
outside, but it had turned into a 0 ohm resistor. I replaced the final just on
general principle, it ohmed out a little different than the new one and
I had a bunch of 3553's around anyway. The 78L08 "fused" most of the
602's and the VFO, it shorted its input to ground and was only putting out 1V,
saving all the "expensive" parts.
I had pulled out all the bad parts, put the new 78L08 in, and fired it
up to see if the RX worked, Jackpot! W7 calling CQ, now where the
paddles? Oh yeah, this thing ain't got no finals in it, pooh. Could have been
worse, could have been a JA at 5NN calling :) Put the final, zener, and
coil in, cranked it up 2W out just like before. Now for the KC-1...
The regulator had gone QRT, put the new one in and turned the radio on,
hmm... no frequency readout, bummer, must have killed it really dead.
Then I accidentally leaned on the key, the familiar .---- .---- -. came
out. Cool, I didn't kill it but it still didn't work. Found the trace
that I was using to ground the keyer was toast, patched the trace and
all is well. (Holding the key closed also grounded the KC-1 so that's what
made it run)
Of course by the time I got it back together the band had folded up,
guess I'll have to fire it up tomorrow night, right after I put that fuse
in...
Thanks Wayne for a sturdy little rig, I figure even it I had to go out
and get the parts I'd be out less the ten bucks. 72 es cu on 30 at 100mw!
-- Chris Cartwright, Technical Engineer |
ccart@vidtel.com --
-- N3XRV ARRL-VE QRP WAS 27/10(w/c) |
http://dns.vidtel.com/~ccart --
-- QRP-L #655 NORCAL #1891 QRP-ARCI #???? NJ-QRP #105 LIQRP
#???? --
71. Subject: Re: SST problem
72. Subject: XMAS SST and winding Toroids.
73. Subject: Re: SST Frequency Range Modification
74. Subject: SST (Discrepancy on rfc-2 (1mh)
75. Subject: Just-built SST and Frequency Range
76. Subject: just-built sst and Frequency Range answer
77. Subject: SST Mods - xtal filter
78. Subject: Another SST on 20 meters -- and a few questions...
71. Subject: Re: SST problem
Date: Mon, 15 Dec 1997 00:18:41 -0500 (EST)
From: Chris Cartwright big 'ol giant grin> I got a nice note
from
NA5N recanting how he killed Dougs SST :) He was right on all counts,
Zener, choke and trace fried.
It took five parts, and all of them were "in stock". The 15uH choke in
the final had been vaporized so I rewound the toroid, and measured it
(six turns instead of ten just like last time). The zener in the output
circut seemed to take the brunt of things. It looked OK from the
outside,
but it had turned into a 0 ohm resistor. I replaced the final just on
general principle, it ohmed out a little different than the new one and
I
had a bunch of 3553's around anyway. The 78L08 "fused" most of the
602's
and the VFO, it shorted its input to ground and was only putting out 1V,
saving all the "expensive" parts.
I had pulled out all the bad parts, put the new 78L08 in, and fired it
up
to see if the RX worked, Jackpot! W7 calling CQ, now where the
paddles?
Oh yeah, this thing ain't got no finals in it, pooh. Could have been
worse, could have been a JA at 5NN calling :) Put the final, zener, and
coil in, cranked it up 2W out just like before. Now for the KC-1...
The regulator had gone QRT, put the new one in and turned the radio on,
hmm... no frequency readout, bummer, must have killed it really dead.
Then I accidentally leaned on the key, the familiar .---- .---- -. came
out. Cool, I didn't kill it but it still didn't work. Found the trace
that I was using to ground the keyer was toast, patched the trace and
all
is well. (Holding the key closed also grounded the KC-1 so that's what
made it run)
Of course by the time I got it back together the band had folded up,
guess
I'll have to fire it up tomorrow night, right after I put that fuse
in...
Thanks Wayne for a sturdy little rig, I figure even it I had to go out
and
get the parts I'd be out less the ten bucks. 72 es cu on 30 at 100mw!
-- Chris Cartwright, Technical Engineer |
ccart@vidtel.com --
-- N3XRV ARRL-VE QRP WAS 27/10(w/c) |
http://dns.vidtel.com/~ccart --
-- QRP-L #655 NORCAL #1891 QRP-ARCI #???? NJ-QRP #105 LIQRP
#???? --
72. Subject: XMAS SST and winding Toroids.
Date: Mon, 5 Jan 1998 10:48:26 -0500
From: Peter_Simpson@3com.com
Well, not really. I bought it last summer, but
last week, I dug out the box and decided I had
enough uninterrupted time to build it.
Wayne has done a super job with this rig! It went
right together in about three hours. 4 toroids,
but they are easy to wind if you know the toroid
magic and have the secret toroid tool I learned
about by reading QRPp :-)
It came right up! Alignment took about 10 minutes.
All you need is a voltmeter and a power meter or CB
type SWR meter. I still can't believe the rig was
so easy to build and align.
I haven't even painted the case yet, because I was
so eager to get it on the air. Heard the WO3B fox
with it, but was unable to work him.
No, I don't get anything for this "celebrity"
endorsement, but I think I got a super rig for the
price, and I would recommend the SST for a first time
QRP rig builder because it's so easy to get on the air.
Cheers,
Peter, KA1AXY
P.S.: Toroids are easy...if the wire goes through
the center of the toroid, it counts as a turn. Make
the secret toroid tool by bending a paperclip into a
hook and using it to pull a loop of wire through the
center of the toroid, until the free end slips through.
Count one turn each time the tool goes through the toroid.
[now I'll probably get in trouble for spilling the beans :-]
73. Subject: Re: SST Frequency Range Modification
Date: Wed, 21 Jan 1998 23:36:53 -0800 (PST)
From: "David D. Meacham"
Paul,
I tried it and had unsatisfactory results. Others have had good results.
I think it has to do with how well the two xtals are matched. I had only
one to try, and did not compare the two.
72, Dave, W6EMD
74. Subject: SST (Discrepancy on rfc-2 (1mh)
Date: Sat, 31 Jan 1998 20:21:19 -0800
From: dave_epps@juno.com
Is anyone else building a SST?
A little discrepancy. On rfc-2 (1mh) the parts list reads color code of
blk-brn-red. The rfc furnished reads brn-blk-red.
I am assuming that brn-blk-red really is 1mh and the parts list is
wrong.
Am I right?
This is my first project with my new Edsyn 951sx soldering station that
Tech Amer had on sale and my soldering looks better than ever.
dave ab5pc fresno, ca.
75. Subject: Just-built SST and Frequency Range
Date: Tue, 3 Feb 1998 10:47:48 -0800
From: dave_epps@juno.com
Sure like the operation of the rcvr, although it seems to only tune 3
khz
and should tune 10. Has anyone else solved this?
I don't have a counter yet (anyone recommend one?), so I listen to the
vfo in another rcvr and it tunes 11.043 khz to 11.046 khz.
tks dave ab5pc fresno, ca.
76. Subject: just-built sst and Frequency Range answer
Date: Tue, 3 Feb 1998 14:23:29 -0800
From: dave_epps@juno.com
Re my earlier post of 3 khz tuning.
I just changed the varactors. Wayne was kind enough to supply another
one
with the kit.
I mounted it on the bottom of the board "easier" and it worked better
than
I expected. It lowered the vfo 10 khz on the bottom and 5 khz on the
top
increasing
the tuning range greatly from before.
Am really happy with the little rig. The rcvr is far better than I
expected.
dave ab5pc fresno, ca
77. Subject: SST Mods - xtal filter
Date: Wed, 04 Mar 1998 20:12:08 EST
From: k7sz@juno.com
I was just wondering if there is a source of mods for the SST by
Wilderness Radio? I have a 40 meter version and would really like to
expand the tuning range without resorting to swtiching between two
varactors or adding a 2nd xtal. Has anyone tried ordering an AT cut
xtal from Jan or Bomar and using this in place of the xtal supplied by
Wilderness? If memory serves, the AT cut xtal will provide the maximum
amount of tuning range.
The xtal filter in the receiver is much too narrow for my liking and I
tried replacing C6 & C9 with 68 pf caps and C7 & C8 with 180 pf
caps...this helped but I needed a wider passband. So, I tried a 56 pf
for
C6 & 9 and 150 pf for C7 & 8. This is much better. These ratios are all
basically 1:3 so I don't see why 47 pf and 120 pf could not be employed
for those who desired a wider bandwidth.
rich K7SZ
78. Subject: Another SST on 20 meters -- and a few questions...
Date: Sat, 11 Apr 1998 20:07:27 -0500
From: "Fred Ringwald"
After letting it sit on the shelf for way too long, I finally built my
20 m SST this morning. After stuffing the board and mounting the case
front, back, and bottom, I fired it up, tuned for minimum smoke, and
found the initial signs encouraging. When I peaked C1, I heard code,
and wondered if this was going to be one of those rare conditions when
my kit worked correctly the first time, with no need for
troubleshooting!
Well, when I proceeded to the transmitter alignment, all was not so
well, as I had zero watts out.
After the visual inspection, and voltage checks, I found that all DC
voltages for U4 were correct, but that on U5, Pins 1, 5, and 8 read
several volts rather than 0 as specified on the table. U4 had all the
right voltages. The initial indication was to suspect U5. However, a
scope look at Pin 3 of U5 showed no signal at key-down. Tracing back
to U4, Pin 4, I also had virtually no signal at key-down. Checking
the U4 oscillator circuit, U4 Pins 7 & 8 showed a garbled, minor
signal, not a nice sine wave.
I decided to try replacing U4 with an NE602 that I had on hand. Yes,
the plated through holes made it a little difficult, but I used the
old technique of snipping all the IC leads and removing them one by
one, rather than applying so much heat so as to destroy the board.
After power up, I still had no power out as indicated on my OHR QRP
Wattmeter, but the scope showed encouraging signs. I had a sine wave
on U4, Pins 7 & 8, and also on Pin 4. I followed the xmtr alignment
procedure and got about one watt out. Since my bench supply was a
little over 12 volts, and not 13.8, I figured that I was doing okay.
A few minutes later, I responded to K4QIL's CQ from near Myrtle Beach,
SC, and we had a short QSO despite the efforts of QRO QRM.
The lingering question is: Why does U5, Pins 1, 5, and 8, show
appreciable voltage, and not 0 as the assembly manual table suggests
they should??
Also I found that with the MV209 at D4, I got a tuning range of
14.043 - 14.058 MHz, rather than the spec range of 14.046 - 14.064
MHz.
Trying the MVAM108, I got 14.032 - 14.051 MHz, which was a little
wider band coverage, but further away from the 20 Meter QRP calling
frequency.
Does anyone have any advice on how I can use the wider band coverage
of the MVAM108, but get 14.060 near the center of the tuning range??
(Or at least within the range by at least 5 KHz??
Finally, since I likely missed this discussion when I was
significantly distracted and couldn't monitor QRP-L shortly after the
SSTs came out, does anyone have any noteworthy experience regarding
mods to this rig to improve it? I am particularly interested in the
9V battery option, band coverage ideas, and I do plan to install a
KC-1, as it has been awhile (apart from today) since I have operated a
straight key. I guess I need to participate in straight key night
sometime!!
Thanks for the bandwidth, and thanks in advance for any help you might
be able to offer.
73s,
Fred Ringwald, AB0AE
fred@innocent.com
79. Subject: Re: Another SST on 20 meters
Date: Thu, 16 Apr 1998 09:27:13 -0700
From: "L.Svec,W.Burdick"
Hi Fred,
Thanks for the input on the SST. I'm looking at the voltages you
mentioned to see if there's a mistake in the table, and I'll get back to you on
this later.
As for the frequency coverage:
There is more variation than I thought there would be in the VXO
crystals I selected for the SST. I was constrained to use off-the-shelf
frequencies to keep the cost of the kit low, and some people have ended up being
just shy of the 14.060 mark with the 20-meter unit. (It still amazes me that
there are standard microprocessor crystal frequencies available that get
us close to the QRP frequencies on all three bands...)
There are several possible solutions, and I'll leave it to you to choose
which way to go. We may change the kit in the future to make this
easier.
1. The simplest (but not the least expensive) thing you can do is order
a custom crystal from ICM, JAN, etc. Specify an HC49-can crystal with a
frequency about 5 kHz above the highest intended frequency of operation.
Custom crystals are on the order of $10, although this varies widely
depending on what lead time you request and how many you order. If the
SST remains a popular kit, we could conceivably use a custom crystal for 20
meters in the future, but only if the volume is high enough to keep the
crystal cost low. (In large quantities, such a crystal might go for $2, but only
with a 3-month lead time!)
2. The basic issue with a VXO is minimizing capacitance across the
crystal to extend the high-frequency end of the range. The MV209 has a fairly
high minimum capacitance--something like 10pF at 8V--so you could try a
different, lower-capacitance varactor here. The MV2104 comes to mind,
but check out the Motorola RF devices catalog (on the web), as well as Zetex
(also on the web). You can also reduce the size of the choke in series
with the crystal: the smaller the choke, the higher the high end of the
range (in general), with a corresponding reduction in tuning range.
3. You can try to put two identical VXO crystals in parallel, one on
the bottom of the board soldered directly to the leads of the one on the
top. If you do this, you can greatly extend the tuning range; in fact it will
tune farther than you want in some cases, necessitating a reduction in
the size of the choke. I haven't tried this on the 20m unit, but it would
be worth expermimenting to see what you get. What you don't want to do is
tune more than about 30kHz. The small pot on the SST is easiest to use
with a 10 to 20kHz range.
4. As I mentioned, reducing capacitance at the high end is everything.
You may want to experiment with a small air-variable capacitor as a
substitute for the varactor tuning, in which case the pot will be
replaced with a panel-mount variable capacitor. Make sure you use one with a
really low minimum capacitance, perhaps 2 to 3 pF.
I hope one of these techniques does the trick! Let us know your
results--
73,
Wayne
N6KR
80. Subject: SST AF Gain and Monitor Tone Problem identified
Date: Tue, 12 May 1998 23:05:19 -0600
From: "mike newbold"
i just assembled a wilderness SST rev. B. The kit went together great
and
is working, but in the digital portion of twenty mtr. i.e. 14.065 to
14.070. should be 14.050 to 14.060. Also I have to crank the AF almost
all
the way to hear anything. And by then the monitor tone is way to loud.
any
one have any suggestions..... please. Catch
a
wave 72 73, Mike K YO newbold@cmn.net
81. Subject: Frequency Range Adjustment Parts change
Date: Sun, 17 May 1998 19:20:36 -0600
From: "mike newbold"
Thanks everybody for you help, my SST is now up and running. pulled the
MV
209 and replaced with the MVAM108 varactor. now works from 14.052 to
14.063. my son added heat with a soldering iron and i pulled. the
toothpick won out over the dental tool clearing the hole. The monitor
volume is still too loud but i was happy to make my first qso with
WD0GXI,
Wayne in Carthage Mo. 519 booth ways. tough copy but pulled off the
inaugural qso. second qso was with KE4DDI, Rick in Aiken, Sc. I got a
569.
The best part was when he sent "rig hr also SST great rig". after a 40
min. qso i tended to agree with Rick ... great rig. this is a great
group
and thanks again to all who helped.
Catch a wave 72 73, Mike K YO
82. Subject: SST not quite there, help
Date: Tue, 12 May 1998 23:05:19 -0600
From: "mike newbold"
i just assembled a wilderness SST rev. B. The kit went together great
and is working, but in the digital portion of twenty mtr. i.e. 14.065 to
14.070. should be 14.050 to 14.060. Also I have to crank the AF almost
all the way to hear anything. And by then the monitor tone is way to
loud.
Any one have any suggestions..... please.
Catch a
wave 72 73, Mike K YO newbold@cmn.net
Subject: SST BLUES NO MORE
Date: Sun, 17 May 1998 19:20:36 -0600
From: "mike newbold"
Thanks everybody for you help, my SST is now up and running. pulled the
MV209 and replaced with the MVAM108 varactor. now works from 14.052 to
14.063. my son added heat with a soldering iron and i pulled. the
toothpick won out over the dental tool clearing the hole. The monitor
volume is still too loud but i was happy to make my first qso with
WD0GXI, Wayne in Carthage Mo. 519 booth ways. tough copy but pulled off
the
inaugural qso. second qso was with KE4DDI, Rick in Aiken, Sc. I got a
569.The best part was when he sent "rig hr also SST great rig". after
a
40 min. qso i tended to agree with Rick ... great rig. this is a great
group and thanks again to all who helped.
Catch a wave 72 73, Mike K YO
83. Subject: Moving SST to 15mtrs
Date: Wed, 1 Jul 1998 13:01:40 -0600 (MDT)
From: marion@montana.com
I was easily able to move a 20mtr SST to 15 mtrs and it is
Working great. Changes to the VXO and output filter and XMIT mixer where
all
That’s required. Covers 21.050 to 21.070 with single varactor. Thought I
would
Let those who had been thinking about it know it works great.
72 Roy AB7CE
Date: Wed, 1 Jul 1998 17:36:38 -0600 (MDT)
From: marion@montana.com
At 01:48 PM 7/1/98 -0600, you wrote:
>marion@montana.com wrote:
>>
>> I was easily able to move a 20mtr SST to 15 mtrs and it is
working
>> great. Changes to the VXO and output filter and XMIT mixer where all
thats
>> required. Covers 21.050 to 21.070 with single varactor. Thought I
would let
>> those who had been thinking about it know it works great.
>> 72 Roy AB7CE
Sounds good Roy! Do you think it could be made to work on 10 meters?
72, Tom WB5QYT
--
I have not explored this to a success. The component values at twenty
Were close enough to work at fifteen for most of the circuits, except
those
Three cicuits. So far moving to ten has involved major circuit changes.
However, moving to 17mtrs is as easier than moving to 15mtrs. Roy AB7CE
84. Subject: Move 20mtr SST to 15mtr: component values
Date: Thu, 2 Jul 1998 11:26:25 -0600 (MDT)
From: marion@montana.com
DOZENS of requests on moving 20mtr SST to 15mtrs, so here is
how I did it. If you make changes or improvements other than these,
please
let me know so I can use them as well.
LOWPASS FILTER
These are standard values from any handbook
L2, L3 = 11turns #26 on T37-6(yellow)
C34, C36 = 150pf, I used silver mica
C35 = 270pf " " "
XMIT MIXER
L1 = 18t #26 on T37-6(yellow)
C27 = 30pf, I used ceramic NPO
VXO
X6 = 25mhz crystals. I used two, one on top, one under
board.
RFC3 = 23t #26 on T37-2(red). This was a critical value
for proper oscillation and range. You may have to adjust
a turn plus or minus, or compress or spread turns to
adjust to desired tuning range.
PA
2.2uh molded choke from base of Q2 to ground.
As above changes were all that was neccessary to put it on 21.050 to
21.070 with the MVAM108. Output was 1 watt, so I put in MRF237(ECG341)
for two
watts out. Its also very easy to move to 17mtrs by using same approach.
Good luck and 72. Roy AB7CE
85. Subject: sst vxo
Date: Thu, 2 Jul 1998 18:20:44 -0600 (MDT)
From: marion@montana.com
I put two crystals in both of my SST's to extend vxo range. One
Is 20mtrs and the other is one I moved to 15mtrs. With the MVAM108
varactors I was able to get about 20khz range. I was experimenting with
different
varactors I had on hand. Was not getting much difference. Then I tried
a MV1404. WOW! The 20mtr version is covering from 14.013 to 14.064. The
15mtr version is covering from 21.039 to 21.073. Scope shows solid
waveforms
across oscillator ranges. I don't know where to get them. They don't
show up in my cross reference, so I don't even know what they are rated
as.
Mine were in a envelope of a dozen, that was in one of Dans Small Parts
20lbs of parts for $10.00. They are not listed on his current page. If
any one
knows what they are rated or where to get them, they might inform the
rest of
the list. 72 Roy AB7CE
86. Subject: SST sidetone
Date: Thu, 9 Jul 1998 12:53:57 -0600 (MDT)
From: marion@montana.com
After unsuccessfully trying various methods to reduce the
Sidetone on my SST, I decided to ask someone who knows the best way to
go about it. That someone was Wayne, N6KR, The rigs designer. The following info
works with mine with some values adjusted for best performance.
--------------
Hi Roy,
Usually there is a good balance between the incoming signals and the
sidetone in the SST. But you're right--if you have to turn it way up,
the sidetone gets loud.
The only sure-fire way to mute the sidetone to a lower level is to
insert a low pinch-off JFET like a J201 into each leg of the audio
connection from the product detector to the audio amp. This is how I do it in the
'40A. Actually you can probably find other JFETs that will work; J310s
are mostly low pinch-off, too. MPF102s will work if you hand-select them
for low pinch-off.
The source leads go to the '602 and the drains to the original
capacitors that go to the '386. Tie the gates together and add a 1 to 10M pull-up
resistor from the gates to one of the source leads. Next, connect a
diode from the gates to the key input. Test the circuit thus far by
keying the rig: you should hear ZERO sidetone at this point, because pulling
the gates low cuts off the JFETS, making them look like an extremely high
resistance. If you hear a click on keydown, put a resistor (start with
1K) in series with the gate diode. If you hear a click on key-up, add a
capacitor from gates to ground; start with about 0.1uF and see if you can go
smaller. (It will depend on the pull-up resistor; 10M and .047 work well in most
cases.)
Once this much is working, you can add a resistor *across* one of the
JFETs (source to drain) to allow some sidetone to sneak through--as much
or As little as you want. It will take a large resistor, something like 1
to 15M in my experience.
Let me know if this does it! You might also post this message to QRP-L
If you have good results.
Thanks & 73,
Wayne
N6KR
-----------------------------
I was able to use some bargain J305s, no matching effort was
done. They completely muted the sidetone. I did not use the resistor to
bypass some of the tone, as I have the KC1 installed, so I use its
sidetone.
In my case the pull up resistor is 2megohms, the capacitor to ground is
.1mfd. Keyline is a 1k resistor in series with 1N4148 switching diode.
No clicks or pops, smooth QSK. Did loose some of the ability to hear other
stations at the same time as in transmit, but don't have to juggle the volume all
the time now either. A big thanks to Wayne. 72 Roy AB7CE
87. Subject: moving SST to 15mtrs
Date: Fri, 10 Jul 1998 10:17:24 -0600 (MDT)
From: marion@montana.com
I recently posted info on moving 20mtr SST to 15mtrs. Heres
Another component change, RFC1 to 2.7uh(or close to it). Improves match
to Filter and recieve.
72 Roy AB7CE
88. Subject: TiCK Audio in SST?
Date: Tue, 14 Jul 1998 22:00:23 -0600
From: "Steve Galchutt"
Where did those of you who put a TiCK keyer in your SST hook up to the
Audio chain. I'm afraid of unbalancing my LM386 by dumping it in on pin
2 or 3?
Where is best?
72...Steve
______________________________________________
n0tu - solar powered QRP & wire antennas @ 7,200' ASL
Monument,Colorado - Grid Sq DM79nb
89. Subject: Mounting a Tick/K8+
Date: Sun, 19 Jul 1998 21:27:05 -0600
From: "Steve Galchutt"
Discovered a neat trick tonite.
While trying to install a Tick/K8+ style keyer in my SST, I saw I was
cramped for space and no room for my keyer which was made up on a
little piece of 1"x 1 1/2" perf board and needed a place to reside.
Plus, I'm thinking of adding some other goodies to the SST and want to leave
rooom for them. So I decided build another keyer and mount it on the
back end of the keyer jack(inside the case of course). I just epoxied the a 8 pin IC
socket to opposite end of the mounting hardware on the jack. And now I'm
wiring it up and hope to have it working for the BB event. Never dreamed
I would have a keyer almost smaller than it's paddle jack! How times change.
72...Steve
______________________________________________
n0tu - solar powered QRP & wire antennas @ 7,200' ASL
Monument,Colorado - Grid Sq DM79nb
90. Subject: Another SST lives
Date: Sat, 01 Aug 1998 18:00:12 -0400
From: Scott Bauer
Hi Group,
Finally, after moving to a new home, I have found
some time to finish building my 20 meter SST kit.
I did have some trouble getting the SST to operate
in the frequency range specified in the manual. After
swapping the 18 mhz crystal out a few times and
changing D4A to D4B, I managed to get a perfect
14.048- 14.061 range. With D4A installed, mv209,
the range was way too high.
The tinkering was well worth it as the SST is a
very nice little XCVR and Im very happy with the
performance.
I managed to work K5OT in the NA Contest. Grabbed
him on the first call. He must have a great station
to hear my 1.5 watts in all of that racket going on ;-))
Now back NA contest with the Teeny Tiny SST !!
What fun it is!!!
72, Scott
91. Subject: NC 40A versus SST - per N6KR Wayne
From: mailto:svecbrdk@well.com
(L.Svec W.Burdick)> >
Sent: Wednesday, May 21, 1997 11:36 PM
Hi Jim,
The SST is a VERY small radio, something of a novelty. My primary
reason for designing it was to try a number of circuit simplification
ideas, but also to provide a radio that would fit in a small day-pack
as part of an ultra-lightweight station. With only 60% as many parts as
a 40A it has some unavoidable compromises. But it also is availble on 30
and 20 meters, which the 40A is not. Here's what you get for the extra $$ for a 40A:
* the 40A covers from 40 to 150kHz of the 40-meter band, while
the SST covers only 8 to 12kHz using its VXO. The 40A is still quite
stable since its VFO runs at 2MHz or so. The SST's design is more
amendable to use on the high bands.
* the 40A has RIT with on/off switch; no RIT on the SST
* the 40A has room on the front panel for the KC1, it's easy to
install; the SST has room in the top cover but the KC1 installation
will not be as easy or as clean
* the 40A has a bit higher power output, typically 3W (SST
typically 2W)
* the 40A has room for a 10-turn pot for the VFO-nice if you add
a turns counter or freq counter such as the KC1
* the 40A has a more sensitive receiver with more audio output
* the 40A has much better AGC than the SST (the SST's LED-based
AGC is cute but not high-performance)
* finally, the 40A comes with a painted and silk-screened case;
the SST has a plain aluminum case that you have to finish yourself
The SST is still fun to use and easy to build, as well as being the
smallest member of the Wilderness transceiver family and covering 20
and 30 meters. But if you don't need the ultra-small size and low
price-tag, or the higher bands, the 40A is a much better radio.
Hope this helps!
73,
Wayne
N6KR
92. Subject: AW: alternate crystals for SST/40
Date: Tue, 18 Aug 1998 20:39:29 +0200
From: "Peter_dl2fi"
I paralleled a second xtal (also from Wilderness, same frequency.
Tuning range is now 7023 to 7038. With another L I had 7018 to 7034
Its somthing to experiment with.
72 de Peter
-----Urspr ngliche Nachricht-----
Von: owner-qrp-l@Lehigh.EDU [mailto:owner-qrp-l@Lehigh.EDU]Im Auftrag
von Allan Taylor K7GT
Gesendet am: Dienstag, 18. August 1998 19:45
An: Low Power Amateur Radio Discussion
Betreff: alternate crystals for SST/40
I have just purchased a SST/40m rig (from WA2HOQ). It is, of course,
centered around 7040. Has anyone successfully arranged a crystal
switching arrangement or socket to allow other center frequencies.
I am interested in occasionally trying 7020-7030 when out in the
sticks. (That's where the JAs are in the morning). Also, what is the
best sourc eof such custom crystals.
--
73 de K7GT
Allan Taylor (a.k.a. Grant) Pleasanton CA
email: k7gt@qsl.net
web page: http://www.qsl.net.k7gt/index.html
93. Subject: Re: SST/40 bandwidth issues
Date: Wed, 19 Aug 1998 08:16:44 -0700
From: Allan Taylor K7GT
I hadn't thought the responses to my SST bandwidth query merited
posting ... but I was wrong! The three suggestions I have received
were:
1) put in a bigger reactor (I assume that means a bigger inductance,
but not completely sure). This approach tends to unstable freq, tho.
2) Put both varacter diodes in (apparently two were supplied with the
SST) with a switch allowing selecting which one to use.
3) Parallel two xtals (yes, identical freq) and a slightly wider
range is attainable. See Super-VXO on the web, 7L4? and G3YCC.
3A) Put in two different crystals, switch between them.
I intend to implement 2 in a test jig and if it isn't sufficient, try
3A.
--
73 de K7GT
Allan Taylor (a.k.a. Grant) Pleasanton CA
email: k7gt@qsl.net
web page: http://www.qsl.net/k7gt/index.html
94. Subject: Tick keyer into SST
Date: Tue, 25 Aug 1998 15:53:51 -0700
From: Allan Taylor K7GT
For compatibility reasons, I have decided to put a Tick keyer (likely
the SuperTick Tick-3) in the SST. While it looks fairly
straightforward, I would like to hear from anyone who has done that.
Exactly how did the keyer audio interface with the SST audio. Planning
on 3V battery inside to power the keyer, so no need for a 5V regulator from rig power.
Having not heard from anyone re a power mod for the SST, I will presume
to try one of my MRF237s in it instead of the 2N3553 and see if I can
get it up to 4W under full throttle.
--
73 de K7GT
Allan Taylor (a.k.a. Grant) Pleasanton CA
email: k7gt@qsl.net
web page: http://www.qsl.net/k7gt/index.html
Subject: Tick inside an SST
Date: Fri, 25 Sep 1998 16:00:28 -0700
From: "Jim Knopf"
Has anyone here put a Tick keyer inside an SST?
If so, what values did you use for R2 and R3, which Embedded Research
Says are "rig dependent." Any problems with using the default resistors supplied,
which are for The Norcal-40A.
.....
-Jim, KI7Q
mailto:knopf@halcyon.com
Visit the "Father of Shareware" at
http://www.halcyon.com/knopf/jim
95. Subject: Re: sst question... 8V to NE612's and LM386.
Date: Thu, 6 Aug 1998 23:34:01 -0600 (MDT)
From: Paul Harden
On Thu, 6 Aug 1998, Bernie Doehner wrote:
> Can't the NE602 (or in my case NE612) and LM386 handle a full 12-14
VDC?
>
> Doesn't driving the NE612's, and LM386's with full 12V produce larger
> swing, and thus louder audio??
Bernie,
The VCC range for the NE602/NE612 is 4.5v to 9v. 9v is the maximum
voltage that should be applied. However, running a 602 in the 8-9v
range, near it's maximum rating, draws more current and has a higher
noise figure. As a result, most designers limit it to 8v, or in some
cases, will insert a diode between the 602 and +8v to cause a 0.6v
drop to run it around 7v to be extra safe and lower the noise.
Applying 12v WILL fry it.
The LM386's are suitable for +12v operation.
The LM386 is rated for +4 to +12v
The LM386A is rated for +5 to +18v
On the LM386, you will often see a 100 ohm resistor between the Vcc
pin (pin 6) and +12v, bypassed with a .1 cap to ground. This is to
keep the current fluctations of the LM386 out of the dc power bus,
AND causes a slight voltage drop so it runs a bit less than +12v for
a slight measure of safety. The LM386A's are a bit more robust with
their 18v rating.
Sometimes running an LM386 from +12v can cause "motorboating." If
this should occur, then bypass the 100 ohm resistor to the Vcc pin
with a large value electrolytic (instead of the .1uF), or lower the
Vcc below 12v.
Your concerns are justified. Always operate passive and active
components well within their maximum ratings. As Gary Surrency noted
on a previous post, tantalums are known to leak, or outright "blow"
by exceeding their maximum rating by only a bit. Another common
error I see is the coupling cap between the PA transistor and the
output filter. At 5W, you have 47Vpp, and a capacitor with less than
a 50V rating will experience excessive heating. The same holds true
for the caps in the output filter. 16V dipped mica's will get hot,
increase the power dissipation, leaving far less power to actually
reach the antenna.
GL, Paul NA5N
Who's blown a few tantalums myself!
Subject: Re: sst question... 8V to NE612's and LM386.
Date: Thu, 6 Aug 1998 22:38:47 -0700 (PDT)
From: Bernie Doehner
> Bernie,
> The VCC range for the NE602/NE612 is 4.5v to 9v. 9v is the maximum
> voltage that should be applied. However, running a 602 in the 8-9v
> range, near it's maximum rating, draws more current and has a higher
> noise figure. As a result, most designers limit it to 8v, or in some
> cases, will insert a diode between the 602 and +8v to cause a 0.6v
> drop to run it around 7v to be extra safe and lower the noise.
> Applying 12v WILL fry it.
AH... The voice of reason. Thanks. 8V it is in the unmodified SST.
Shall leave it that - thanks..
> The LM386's are suitable for +12v operation.
> The LM386 is rated for +4 to +12v
> The LM386A is rated for +5 to +18v
>
> On the LM386, you will often see a 100 ohm resistor between the Vcc
> pin (pin 6) and +12v, bypassed with a .1 cap to ground. This is to
> keep the current fluctations of the LM386 out of the dc power bus,
> AND causes a slight voltage drop so it runs a bit less than +12v for
> a slight measure of safety. The LM386A's are a bit more robust with
> their 18v rating.
Not in the SST design, it goes to the 7808 instead..
> Sometimes running an LM386 from +12v can cause "motorboating." If
> this should occur, then bypass the 100 ohm resistor to the Vcc pin
> with a large value electrolytic (instead of the .1uF), or lower the
> Vcc below 12v.
I may try this to see if I can get a bit more audio out of it, thanks
For the warning though.
> Your concerns are justified. Always operate passive and active
> components well within their maximum ratings. As Gary Surrency noted
> on a previous post, tantalums are known to leak, or outright "blow"
> by exceeding their maximum rating by only a bit. Another common
> error I see is the coupling cap between the PA transistor and the
> output filter. At 5W, you have 47Vpp, and a capacitor with less than
> a 50V rating will experience excessive heating. The same holds true
> for the caps in the output filter. 16V dipped mica's will get hot,
> increase the power dissipation, leaving far less power to actually
> reach the antenna.
:)
Oh yes... Thanks!
Bernie
96. Subject: Tick keyer into SST (Perhaps Allan now knows how.)
97. Subject: SST fine tuning mod?? (Perhaps Allan now knows how.)
98. Subject: SST Labeling (Perhaps Rick now knows how)
99. Subject: 40m SST Crystal
100. Subject: SST-40 VXO expanded range - component values
101. Subject: RE: LM386 question answered
96. Subject: Tick keyer into SST (Perhaps Allan now knows how.)
Date: Tue, 25 Aug 1998 15:53:51 -0700
From: Allan Taylor K7GT
For compatibility reasons, I have decided to put a Tick keyer (likely
the SuperTick Tick-3) in the SST. While it looks fairly straightforward,
I would like to hear from anyone who has done that. Exactly how did the
keyer audio interface with the SST audio. Planning on 3V battery inside
to power the keyer, so no need for a 5V regulator from rig power.
Having not heard from anyone re a power mod for the SST, I will presume
to try one of my MRF237s in it instead of the 2N3553 and see if I can
get it up to 4W under full throttle.
Have a 2nd op (N6RY, Terry) for the Sept 18,19 Yosemite QRPxpedition to
Grid squ DM07, Hayden Lake (elev ~7700') overlooking the Tuolumne River
canyon. Should give us a great shot at EU on 20m. Can't wait!
--
73 de K7GT
Allan Taylor (a.k.a. Grant) Pleasanton CA
97. Subject: SST fine tuning mod?? (Perhaps Allan now knows how.)
Date: Mon, 31 Aug 1998 10:30:15 -0700
From: Allan Taylor K7GT
Is there a 3-turn or 10-turn pot that will fit in the space of the
existing tuning pot in the SST? It looks cozy to me and would like to
know if someone has done this potential mod.
--
73 de K7GT
Allan Taylor (a.k.a. Grant) Pleasanton CA
98. Subject: SST Labeling (Perhaps Rick now knows how)
Date: Fri, 04 Sep 1998 22:00:07 EDT
From: wa8rxi@juno.com (Rick Arzadon)
Fellow QRP fans;
Built an SST and would like to paint and label the case.
In the manual is artwork for 1:1 copy to a transparency.
The question is...... How do I glue this clear plastic to the case?
TNX ES 72, Rick Arzadon - WA8RXI Taylor, MI.
Date: Tue, 29 Sep 1998 18:01:31 -0500
From: "Karl Heimbach"
To:
Gang,
I'd like to try a parallel HC-49 11.046 MHz microprocessor crystal in a
40m SST in an attempt to increase the tuning range. My Mouser catalog does
not show it to be a stock item.
Anyone have an idea of where I might get one?
Thanks,
Karl - W5QJ
Subject: Re: 40m SST Crystal
Date: Tue, 29 Sep 1998 16:18:53 -0700
From: "Allan (Grant) Taylor"
The crystal in question is a Digikey X025-ND.
I have already checked with International Crystal Mfg Co. with the
intent of obtaining a few additional crystals to allow coverage down-band.
Those crystals will cost $13.68 each, plus UPS charges. I can get you
Further info if you would like regarding that option. I am contemplating
instead getting a 2nd NC40A, then repackage the new NC40A for field
use (pots on top, etc.)
K7GT
--
73 de K7GT
Allan Taylor (a.k.a. Grant) Pleasanton CA
100. Subject: SST-40 VXO expanded range - component values
Date: Mon, 5 Oct 1998 22:51:23 -0500
From: "Karl Heimbach"
To:
Gang,
I've read with interest the "Wilderness SST Notes" on G3YCC's webpage.
Of particular interest has been the commentary on expansion of the VXO
tuning range. Perhaps the following may be of interest to others wanting to
expand the range of their SST-40.
Tabulated below are results of a couple of combinations of crystals and
inductors and the tuning range observed with each combination.
In all cases, the X6's were 11.046 MHz HC-49's (DigiKey X025-ND) and
RFC3's were molded epoxy chokes.
Case: Design 1
RFC3 value: 15 uh 15 uh
# of X6's: 1 2
Tuning: 7.034-7.041 6.9814-7.0319
Range: 7 KHz 50.5 KHz
Case: 2 3
RFC3 value: 13.2 uh 13.2 uh
# of X6's: 2 3
Tuning: 7.019-7.040 6.949-7.035
Range: 21 kHz 86 KHz
Case: 4
RFC3 value: 11 uh
# of X6's: 3
Tuning: 7.007-7.042
Range: 35 KHz
I stopped with Case 4. RF output is approximately 3 watts throughout
the tuning range with a clean sine wave also observed throughout the range.
On air reports have been good.
Karl - W5QJ
101. Subject: RE: LM386 question answered
From: Ed Loranger [SMTP:we6w@qsl.net]
Sent: Tuesday, October 13, 1998 2:08 PM
Subject: RE: LM386 question answered
Howdy Alan et. al: You got this a bit wrong :)
I mentioned that the 220 to 470 uF Electrolytic
go from the +V input to the LM386 and Ground.
Not the 1/8 pin feedback network.....
I hope this opens up some ideas for you.
GL OM.
-Ed
K7GT mentioned:
A higher Vcc does allow wider swings in the case of high input
signals.
So, on that basis rerouting Vcc rather than regulated (+8V in my case
with the SST) to the chip may help a little on strong signals. Another
suggestion (WE6W) was to put in a HUGE capacitor across pins 1-8. It
would seem the effect of that would be to make sure the internal
biasing network is REALLY out of the picture.
--
72, Ed WE6W (CW only/VP-0); http://www.qsl.net/we6w Santa Rosa, CA
QRP-Z#106 QRP-L#1068 AR#112 NC#2227 ARCI#9397 QAA#006
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