[Hammarlund] Old Hammarlunds

[Carl]

Also realize that the one cap across the variable is there for all bands. 
That means other values may be needed for the lower ranges that have to be 
wired into the oscillator circuits.

Later production SP-400's had TC but I dont have that detail handy at the 
moment.

Carl


----- Original Message ----- 
From: "Kenneth G. Gordon" <kgordon2006 at frontier.com>
To: <Hammarlund at mailman.qth.net>
Sent: Monday, April 11, 2011 7:33 PM
Subject: Re: [Hammarlund] Old Hammarlunds


> On 9 Apr 2011 at 15:44, Chuck McGregor wrote:
>
>> There was an earlier note on temperature compensating the SP-200
>> printed in QST for Feb 57, page 58.
>
> That amounts to adding only 3.3 pfd worth of TC capacitor with "as high
> negative coefficient of compensation as available" connected in parallel 
> with
> the oscillator tuning cap, then realign.
>
> Supposedly, this cut the drift down from well over 50 Khz, to 200 CPS.
>
> Sounds simple enough.
>
> Anyone know where one can get some negative 750 PPM, or 1500 PPM, TC
> caps?
>
> Ken Gordon W7EKB
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