[Amps] Grid Dipping the Pi network in a new amp?

Steve Thompson g8gsq at eltac.co.uk
Wed Jul 18 03:05:48 EDT 2007


STEVEN & NANCY FRAASCH wrote:
> Bob:
> 
> The antenna analyzer SHOULD have a source impedance of ~50 ohms.  If it didn't it would cause a reflection (or possibly reduce or cancel a reflection) if it presents an odd conjugate condition other than 50 ohms real.
Is that necessary here? If you hang a resistor on the anode to represent 
the wanted load resistance, then the pi network transforms that so that 
you see 50 ohms looking into the antenna socket. I think the source 
impedance of the instrument measuring the 50ohms doesn't matter.

Steve

PS the other day you said we all make mistakes. My turn yesterday - I 
was mad at someone after a phone call, and a moment's inattention put 
150W up the input of my network analyser. First time in 30 years.


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