[Boatanchors] HQ-170A

[rrkrr]

The HF oscillator for the first heterodyne frequency conversion in the 
HQ-170 uses parallel LC resonators that are switched in by the 
bandswitch.  The capacitive components of these are made up of a 
combination of fixed and variable capacitors.  In my case it turned out 
that one of the fixed capacitors was defective, and was highly sensitive 
to temperature.  I replaced it and the 40 meter frequency stability was 
greatly improved.

I suppose the way to really fix this is to swap out the LC resonators 
for a bank of crystals, but if I were going to do that I would then want 
to get rid of the pentagrid mixer tubes and........

Bob
K4ERR


Magoo wrote:
> I have owned one of these for several years; I love using it but it 
> drifts. It often takes over 2 hrs to settle down, even when the 
> filaments have been lit on the oscillator for the previous 24 hrs.
>
> I have tried several different 6C4 oscillator tubes of various brands 
> with no luck in reducing the drift (which starts 5-7 khz high and 
> eventually drifts right on calibrated frequency).  It sounds like I 
> will have to change some caps in the oscillator.
>
> I also have a Drake 2B and 2BQ....no drift and this receiver performs 
> as well or better than the Hammarlund...but it doesn't cover 160M!
>
> For casual listening on CW the HQ-170A is great but to leave it on a 
> net frequency if it has not been on for several hours is frustrating.
>
> Bill, VE3NH
> _______________________________________________
>