[AMRadio] Heathkit -VF-1 low band band spread


Rob Atkinson ranchorobbo at gmail.com
Mon Jul 11 18:25:49 EDT 2016


My July ER just arrived today and there is an article in it by W1TG on
fixing problems with the VF1.  Not sure but maybe this article will
provide some clues or ideas.  He had a jumping frequency problem for
one thing, and it turned out to be the band switch.

73

Rob
K5UJ


On Thu, Jul 7, 2016 at 1:39 PM, John Coleman <jc at pctechref.com> wrote:
> Ok let me see if I can explain my problem.
> # 1
>         The VFO works and cailbrates at both ends of the 40 meter band.
> #2
>         I made sure, that I was using the large rotor plates beginning with full mesh, and the dial set to just below the 3500 khz point.
> #3
>         I know that if you  desire to cover less band frequencies, then the tunning capicor must be less percentage of the parrallel capacitors.
> #4
>         I have worked this thing back and forth and it all ways comes out that the coil slug is screwed out all the way (min L) and the trim cap is max.
> #5
>         I hit 3500 khz before I get to the low end of the dial. If I dial lower the freq actually goes well below 3500 khz before I get down to 3500 on the dial.
> #6
>         I hit 4000 khz before the dial gets all the way to 4000 and it continues higher if I continue to turn it untill the main tunning cap is full un-meshed.
>
> I could take turns off of the coil and add extra capacitors across the tunning cap.  But I just doesn't make since.  Or perhaps I could use the smaller rotor plates (maybe that is the answer and the large rotor for the high band).
>
> I don't think the 510 pf caps that make up the feed back divider at the grid and cathode would be a culprit.
>
> Help,
> John, WA5BXO


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