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Re: Sad reality of stock vfo

Rahul Srivastava
 

Hi ,

Can try putting a couple of 4148 on either side of tuning pot depending upon the direction to provide some compensation for thermal drift.

Rahul VU3WJM


On Sun, Jan 1, 2017 at 1:17 PM, Ashhar Farhan farhanbox@... [BITX20]
wrote:
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raj,

the varactors have a bad temperature coefficient. they contribute too.

- f

On Sun, Jan 1, 2017 at 11:52 AM, Raj vu2zap@... [BITX20] <BITX20@...> wrote:
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NP0 capacitors for C94 95 96 WILL tackle the heat problem Farhan!

Happy new year!
Raj

>2. The culprit is heat. The RF amplifiers have significant current, there are three of them. The heat dissipates through the ground plane and heats up the VFO components. This heat would be missing if we used through hole components as those components are off the board.
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