[Milsurplus] Smart People: BC-9 TX/RX Freq Shift- Q?

[Kenneth G. Gordon]

On 5 Feb 2017 at 4:51, David Stinson wrote:

> > I think both your friend, AND Hugh have valid points.
> 
> I don't know why, but I haven't received any mail from
> Hugh. Yours is the only reply I have seen.
> Nor is anything related in my Spam folder. No idea why, but
> I'd value Hugh's input. Can you forward? Thanks.

I can't forward it because after reading it, I assumed you had got it, and deleted it.

Basically, what Hugh said was that the change in plate voltage from 70 volts in receive to 
120 volts in transmit changes the tube's impedance and that causes frequency shift.

Which is true. As I said, I believe that is the  so-called "Miller Effect" (look it up).

However, in MY opinion, I don't believe that could cause a +/- 12 KHz shift at 4 MHz....by 
itself.

I think your other friend who landed on the difference in "Q" of the antenna also plays a big 
part in that frequency shift.

In any case, I am most anxious to see how your BC-9 works with its original antenna 
system.

Another mentioned that the fact that the final tank coil is out in the breeze ensures that 
anything moving around in the near vicinity will also cause frequency shift.

Ken W7EKB

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