[Collins] Collins Digest, Vol 62, Issue 6

[Dr. Gerald N. Johnson]

On Tue, 2009-06-09 at 14:18 +1000, Pete Williams wrote:
> 
>    2. Re: Collins filters... (Dr. Gerald N. Johnson)
> 
> 
> Thanks Gerry... that was the info I was after... In this unsophisticated
> Check, the diode detector to the Y amp in the cro follows the filter under
> test... it is a simple rf probe -cap .01 from generator, Ge.diode to ground
> and a 2.2 M to the Y amp.  --- any problems with that?
> Thanks for the  help.
> Pete VK3IZ
> 
> 
That's a nonlinear load and not high impedance, so I'd run the output of
the filter with it series resonated to probably 500 or so ohm resistor.
But around here for the past 43 years, I'd just drive the 5 MHz or
faster scope direct, forget the detector. Actually a half MHz scope
would be plenty wide band for a 455 KHz mechanical filter. Just that
I've had a 5 MHz or better that long. I only use diode detectors above
460 MHz where my most recent scope stops working. And that scope has
been here more than 30 years.

73, Jerry, K0CQ