Hi Folks,
Just worked Al, K0FRP, for the first 20-meter SST contact! I hope to be on
the air with the SST quite a bit over the next week, probably in the
morning, and possibly mobile as well (in the parking lot at work at lunch
time :).
When I put the SST on 20 meters, I found that the band had heavy QRN from
local power poles. Solution? A Buzznot! The Buzznot noiseblanker fits
nicely just above the SST's receive mixer, so I'm going to include
connection points for it in the final version of the PC board.
On to the real business:
Since so many people have been prodding me for SST info, here is the latest.
The SST is going to be offered for 20m, 30m, 40m, and 40m/novice.
The final parts count is about 77. To put this in context, the NW8020 has
150 parts, the NorCal 40A has 120, and the 38-Special has 100. My goal
with the SST was to see just how low you could go and still have really
good performance.
The SST receiver is 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
(more on this in the article). 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.
The transmitter has *really* fast, exceptionally clean (I mean 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.
I decided to go with a varactor-controlled VXO rather than a VFO.
Stability is excellent. 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 will be supplied
unfinished. Since the box is so small, I went with .050 aluminum to reduce
weight. (With a KC1 on the top and an internal 9V lithium battery, the SST
makes a great TFR! It so completely out-performs the 40-9er that I wish I
had done the SST first :)
I'm sending the article to Doug today, and it will appear in the next QRPp.
The article describes primarily the 40m version, but component details on
all bands will be provided with the kit and published in a subsequent issue
of QRPp. The kit will come with all controls, connectors, and cabinet.
The club price will be announced in the article, and orders will be taken
until May 1 at that price. Delivery of the kits will likely be in late
May.
I don't know if orders will be taken prior to the publication of QRPp. I'll
have to check with Bob Dyer at Wilderness Radio, who is doing the kitting
for the club. In any case, there will be *no limit* on the number of kits
sold at the club price as long as the orders are received by May 1. After
that, field-test data will be used to update the design, and if all goes
well it may become a Wilderness kit at a slighty higher price. Stay tuned
for details.
73,
Wayne
N6KR
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