[ARC5] Receiver input impedance...

[Kenneth G. Gordon]

On 20 Oct 2014 at 8:08, J Mcvey wrote:

> The ARC-5 system was designed for low-Z (12 ohm?), short capacitive 
> antennas. So, in this case, the low Z side would be at the receiver terminals? 

Yes. Those are correct, yet the receiver input-impedance IS about 4K ohms.

Kinda like a VTVM with an 11 megohm input impedance being used to 
measure a battery's voltage.

Probably this was done in this case so that one antenna could be connected 
in parallel to mulitple receivers which all tune to different frequencies (which 
was done in the original setup) without causing any interaction or signal loss.

Possibly, the input circuitry was done the way it was so that it inherently is 
already a type of impedance transformer.

As per the discussion here, I am coming to the conclusion that matching that 
impedance is not really necessary, nor particularly useful or helpful, and it 
appears, at this point, that doing so is hardly worth the effort.

To satisfy my curiousity, I MAY build an 80:1 Un-Un and take some 
measurements....just to see...but at this point, I would not expect there to be 
a noticeable improvement.

Ken W7EKB