[AMRadio] National PW Dial

John Coleman ARS WA5BXO wa5bxo2006 at pctechref.com
Tue Mar 13 09:19:27 EST 2007

I may do this again Wayne as this has sparked and interest for me.  A
project of this type makes one appreciate the workmanship and engineering
that goes into some of the old radios that tracked so well.  Frequency
counters are wonderful pieces of equipment but when you throw the switch on
a 100KC calibrator and pull the VFO/PTO dial zero beat just as the dial mark
passes zero, it really makes you feel good.


-----Original Message-----
From: amradio-bounces at mailman.qth.net
[mailto:amradio-bounces at mailman.qth.net] On Behalf Of Sara & Wayne Steiner
Sent: Tuesday, March 13, 2007 6:13 AM
To: Discussion of AM Radio in the Amateur Service
Subject: Re: [AMRadio] National PW Dial

I found that the variables in the  command set series of transmitters are
very close to straight line frequency.  Some years ago I built a variable
osc. using one of those caps and a mechcanical digital  counter and was in
within  less than .5 khz over a 200khz band (160m). I of course had to do
some trial and error plate bending.
Over a 25 khz portion of the band and a small variable osc padder I could be
"spot on".

wayne , N0TE

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