[ARC5] BC-230 first run

[Kenneth G. Gordon]

On 30 Mar 2016 at 8:52, AKLDGUY . wrote:

> Somewhere in the past 50 years I read that the three ARC-5 / SCR-274 tuning
> capacitors are either 100 or 150 pF (can't remember which). It would be an
> interesting exercise to use one in an oscillator, then substitute known fixed
> caps until the same frequency is achieved. Someone with time on their hands?

Somewhere within the last 50 years, **I** learned that the single VFO tuning 
cap in the ARC-5 transmitters has plates made of Invar for temperature 
stability. 

This makes sense when we realize that the transmitters were set to 
frequency on the ground, sometimes in the tropics, then flown to 
high-altitude where the temps were sub-zero.

This cap is noticeably different from the other two caps, both in construction 
and in the drive mechanism.

Ken W7EKB