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Re: Sad reality of stock vfo


Thomas Noel
 

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John,

As I said - I knew from others¡¯ experience that the stock design has some significant limitations. I just had no previous personal experience with such builds. I have read of quite a few design mods that offer improvement. The design is simple and easy to mod as Farhan intended. I built the stock design as a starting place for learning.?

I was surprised to see the drift so severe that it is hard to hold frequency during an ¡°over¡±. I have made more than a dozen QSOs in less than two hours of operation. The operator on the other end even commented that I was drifting off frequency.

I would like to continue to experiment with the all-analog radio before moving to the DDS VFO.

Where exactly would you start? Replace the resistors as suggested by Farhan? They were included with my purchase. Which capacitors would you replace to stabilize the VFO, and change just the type, or change any of the values? My tuning range is just where I would want it now.

If anyone can give me a step-by-step attack plan in order of best anticipated return on effort, I would appreciate it a lot.

Thomas W Noel
KF7RSF

On Dec 31, 2016, at 7:28 PM, John Greusel greusel@... [BITX20] <BITX20@...> wrote:


Thomas,
That's not optimal behavior for that sort of design. It can do much better than that. I think you should revisit the traditional solutions for such problems and them implement them before moving on- NPO and styrene capacitors might be a start.

John
KC9OJV



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