Re: NorCal 40A

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From: Doug Hendricks (dh@altair.csustan.edu)
Date: Wed Oct 05 1994 - 23:55:14 EDT


Guys, here it is, more exciting news from NorCal QRP Club. Wayne Burdick
sent me this article in response to a discussion that was held at our
regular club meeting Sunday. Jim Cates, Eric Swartz and I have finally
convinced Wayne that the club needs another run of NorCal 40's. Wayne
agreed that we needed to, but he wanted to make some improvements and fixes.
The club is taking orders from now until Jan. 1, and the price will stay the
same, $89.00 plus $5.00 shipping for US residents, $89.00 plus $6.90 state
tax plus $5 shipping for California residents for a total of $99.90. And
$89 plus $10 shipping for DX orders. Send your checks and/or money orders
made out to Jim Cates to:

        Jim Cates, WA6GER
        3241 Eastwood Rd.
        Sacramento, CA 95821

This offer is only for NorCal members. We need to do that because we are
not a commercial venture. To become a NorCal member, send $5 to Jim Cates
at the above address. We are looking at a Feb. shipping target. But again,
we are at the mercy of our suppliers.

I had intended to hold this for the December issue but I just couldn't wait
to tell the World that the NorCal 40A is available again.
Doug, KI6DS

>The NorCal 40A:
>Solid Evidence that
>Darwin was Right!
>
>Wayne Burdick, N6KR
>
>As predicted, NorCal members modified, molded, prodded, painted, tweaked,
>torqued and tested thier NorCal 40s during the past year. The result is
>that we've learned a lot about how to improve the basic design.
>
>Does this provide evidence for the Theory of Evolution? You betcha! A
>small number of NorCal 40s mutated or mated their way into superior
>fitness, and the new generation--the NorCal 40A--is ready to squirm out of
>its shell and into the sunshine.
>
>The NorCal 40A has a number of improvements over the original design,
>including a few ideas borrowed from its cousin, the Sierra, but the price
>will stay about the same. I hope the kit will appeal to some of our newest
>members, many of whom missed out on the limited run of the NorCal 40 and
>Sierra.
>
>Here's the list of improvements that I expect to include in the new design:
>
>1. New PC board layout--cleaner, with solder mask to reduce shorting, etc.
>2. Toggle switches for RIT and ON/OFF will have threaded bushings, making
>the front and rear panels MUCH more stable.
>3. RIT circuit from the Sierra will be used--fewer parts.
>4. Better grounding around the crystal filter will yield less filter
>blow-by on strong signals.
>5. AGC circuit (the two JFETs) will be linearized for better strong-signal
>performance. I'll also include a pot for adjusting the AGC level,
>eliminating the infamous "R6" problem. (High 5's all the way around!)
>6. The VFO will use a new, more stable pot with greater rotation range,
>and the VFO will cover 50KHz standard rather than 35KHz. Also, there will
>be more space available to put in a 10-turn pot.
>7. The VFO and RIT resistors will all be scaled by a factor of 10 to allow
>the use of a 10K VFO pot. It's easier to find a 10-turn 10K pot than 100K
>(thanks, Doug!).
>8. The TX mixer's 4.915MHz crystal oscillator will use a 270pF rather than
>150pF cap to reduce the signal amplitude into the NE602, which will in turn
>reduce output harmonic content.
>9. The TX monitor pitch and RX BFO pitch will both be independently
>adjustable as it is on the Sierra.
>10. Overall RF gain will be improved by using a high-Q tank at the input to
>the RX mixer. The original circuit used a low-Q 15uH choke.
>11. VFO and transmitter output will both be improved--or at least made more
>consistent--by switching to 2N4416s or J310s instead of MPF102s. The
>latter can have poor transconductance. I'll also be choosing different
>JFETs for the AGC circuit to improve signal handling.
>12. The DC power connector will be a standard 2.1mm barrel, as on the
>Sierra, rather than the RCA jack. This will prevent power supply shorts.
>13. I'll try to include 80-meter modification instructions. This will
>involve changing around 10 to 15 component values.
>14. The long standoffs on the top of the PC board will go away, in favor of
>Sierra-style plastic latches. (One thing I learned from attending NorCal
>meetings is that people like taking the covers off of their rigs and
>showing them off!) The latches will mean no more lost screws, and will
>also allow easy access to interior controls and modifications, as in the
>Sierra.
>15. The manual will be updated, of course, and will include some features
>from the Sierra manual, such as the DC voltages chart.
>
>The NorCal 40A schematic will be reprinted in a later issue of QRPp so that
>anyone can, if they wish, modify the NorCal 40 in the same way.
>
>Thanks again for all of your help in refining our club's classic rig. Who
>knows? Perhaps another year of field testing by new members will culminate
>in a NorCal 40B. If this keeps up, we'll have to honor Mr. Darwin with a
>QRP DXpedition to the Galapagos Islands....
>
>


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