NorCal 40 rig

---------

From: Wayne Burdick (burdick@interval.com)
Date: Mon Sep 13 1993 - 13:21:34 EDT


Fellow QRPers,

I wanted to clear up a few points about the NorCal 40, the first project of
NorCal, the Northern California QRP Club, as reviewed by Chuck Adams in a
posting yesterday. (And by the way, Chuck, sorry I missed the Foothills
flea market on Saturday. Had I known what the turnout at the NorCal setup
was going to be, I would have planned to be there to talk about the rig
design. Maybe next time.)

First, this is a club project--not a commercial product--which is why we
intended a run of only 50 kits to start with. A club project is evolving,
malleable, imperfect; a commercial product should not be. To the extent
that it *may* become a product someday, I suppose we could consider it Beta
test.

Another important difference between a club rig and a commercial one is, in
this case, Doug Hendricks and Jim Cates. These two tireless gentlemen are
not your typical purchasing, shipping, and sales department: they're doing
this on thier own time, and I am grateful for thier help in making this rig
a reality. So while I appreciate Chuck's suggestion that you all mail your
checks in early, I'd like everyone to keep in mind that the $75 price of
the rig reflects a total payroll of $0.00 divided three ways. Our intent
is to give club members a chance to build and operate a rig together, not
to make money, which we won't, so the bottom line is a limited supply that
will first be offered to club members.

Now, regarding Chuck's review:

The dimensions are 4.6"W x 4.5"D by 2.2"H (good eye, Chuck). The case is
custom made in four parts that attach directly to the PC board, making it
very easy to remove either the top or bottom. That's one feature of the
HW-8 that I always appreciated. All components, controls, and connectors
also mount to the PCB so there's no chassis wiring at all. And we left
plenty of room in the case for mods--this is, after all, an evolving,
malleable and imperfect club project. Other points:

- yes, both the key jack and headphone jack are 3.5mm, by popular demand;

- no, the antenna jack is a BNC;

- the RX current drain is nominally 15mA but can go higher when loud
signals are present; TX current drain is nominally 175mA at about 2 watts
out;

- measured PA efficiency was 83% on the first rig built, 75% on the second;
I used an MRF237 in the first one and got 1 to 3.3 watts out, while Doug
(KI6DS) used a 2SC799 and got 1.2 to 2 watts out; the final design may use
an MRF607;

- the receiver has a novel differential JFET AGC circuit in the AF channel
that draws no current;

- the receiver is a superhet, with the I.F. at 4.915 MHz and the VFO at a
nominal 2.085MHz.

Finally, the known quirks and limitations:

- there isn't enough AF output to drive a speaker;

- the AGC range is limited (JFETs go nonlinear at some point);

- like all NE602-based receiver designs, you *will* need the RF gain
control at times;

- the VFO tuning range is only 35 to 40 KHz using the varactor diode
(presenting one of many opportunities for modification);

- there is a good, loud "birdie" at 7.022 MHz that is a blessing if you're
using it as an extra-band-edge marker during VFO alignment, but a curse if
you're using the extra band; fortunately, the birdie can be easily subdued
with a series LC circuit on the back of the board, as explained in the
manual;

- there is no I.F. amp--not really needed on 40 meters--so modifying the
rig for 20 meters or above isn't a good idea.

I hope that clears things up. If you're interested, please go ahead and
*write* to Jim (Jim Cates, WA6GER, 3241 Eastwood Road, Sacramento, CA
95821) to get onto a waiting list. But don't send your precious dollars
yet since we may be sold out! We *may* do a second run. If things get
wildly out of hand, the rig may become a commercial product, with a bigger
price tag, sales tax, phone support, etc., etc.

Thanks again, Chuck, for your visit to NorCal territory. I hope others
here on QRP@think.com will give us feedback on the rig design and get a
chance to try it out.

Special thanks to Doug Hendricks for eeking out bargain prices from unwary
Silicon Valley surplus houses, keeping the kit price low!

Wayne Burdick
N6KR
wayne@interval.com
(415) 354-0928, (415) 592-2700


Search QRP-L Archives

[ QRP-L Archive | ]
[ 1993 | 1994 | 1995 | 1996 | 1997 | 1998 | 1999 | 2000 ]

---------

This archive was generated by hypermail 2b29 on Fri Jun 02 2000 - 11:26:17 EDT

kd4ab@kd4ab.org