[ARC5] BC-453 drift test

[Kenneth G. Gordon]

On 10 Jan 2018 at 23:45, J Mcvey via ARC5 wrote:

> 
> I recapped this radio and tested the LO drift afterwards.
> Coupling the plate via 7pf cap and a x10 scope probe to a frequency counter, the 
> results were as follows:
> The LO dropped in frequency at a rate of about 1 HZ / second upon power up.
> The drop rate slowed until it more or less stabilized an hour later 700 Hz lower 
> than the start up
> measurement.
> Once at the bottom of the descent, it would sit and go up and down a couple of 
> Hz in a very slow undulation.
> 
> I guess this a normal warmup scenario? What say you?

That sounds exactly like what I and Bill Cromwell experienced. You MAY be able to 
minimize the "up and down" business by regulating the filament voltage.

As I remember it, Bill found this to be true.

I have not yet done that, but intend to do so.

Ken W7EKB



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