[ARC5] BC-453 drift test

[Tom Lee]

Without knowing the LO frequency it's hard to give a precise answer, but 
that warmup drift represents roughly a couple tenths of a percent at 
midband. That sounds reasonable, as does the warmed-up drift. The 
dropping in frequency during warmup is consistent with the inductor and 
capacitor expanding as it heats up (L and C both increase under a linear 
expansion), so it makes sense.

-- 
Prof. Thomas H. Lee
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420 Via Palou Mall
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On 1/10/2018 3:45 PM, 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?
>
>
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