I currently have a PM-3A and used to own an HW-8. The HW-8 does have a
better dial, similar to an HW-101, with calibrations uniform for all bands
and fairly good bandspread. The PM-3A has a crude, slide-rule type dial,
with 7.0 - 7.3 on the 40-meter scale. However, for 20-meters, it simply
doubles the 40-meter VFO output. Thus, the 20-meter scale goes from 14.0 -
14.6, far beyond the 20-meter band and not enough bandspread for cw.
There's a good article in the Oct. 1974 QST by the late Doug DeMaw on
repackaging the PowerMite. While I wouldn't canibalize my PM for his
project, he does have a good way to increase bandspread. He says in the
article that if you don't want to mess up your PM, you can simply paste a
new, cardboard dial over the original one. His bandspread modification
involves putting two fixed capacitors on the VFO board, one in series and
one in parallel with the tuning cap. It requires few wiring changes and can
easily be removed to put the unit back into its original condition. With his
modification, the PM-3 covers only the cw portion of 40, from 7.0-7.150. The
20 meter, of course, is from 14.0 to 14.3, which is much better than before.
I'm planning to do this modification to my PM-3A. I once had a PM-2B which
had been so modified by its original owner and it worked well.
DeMaw's other mods include adding an RF stage, TVI filter and replacing the
unshielded wire with RG-174 mini-coax. With these mods, the PM should be as
good or better than the HWs, as they both use direct conversion receivers,
with all the shortcomings they involve.
I plan to try these mods, without butchering the unit beyond repair.
73, Winston K4CWQ
----- Original Message -----
From: Sherrill WATKINS <SEWATKINS@dgs.state.va.us>
To: <tentec@contesting.com>
Sent: Tuesday, April 04, 2000 10:27 AM
Subject: [TenTec] Powermite vs. Heathkit HW-7
>
> Ten Tec Fans: I will really appreciate receiving comments from those who
have used both the Ten Tec Power Mite and the "Griefkit"
> HW-7 or 8 series of qrp rigs. I am aware that the "Griefkit" is a
somewhat later design than the Power Mite but do they offer
> significant performance improvements or advantages? A friend of mine says
the "Griefkit" has a better calibrated dial? - I look
> forward to receiving comments on this - THANK'S! - Sherrill W. k4own
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