[AMRadio] receiver input Z

JAMES HANLON knjhanlon at msn.com
Sat Jan 18 13:43:52 EST 2014

Ever since I started working the Classic Exchange in 1977, I have been using multiple receivers with two rotary switches that connect two of them to the same antenna lead at the same time.  Another pole on the switches connects their audio outputs to my headphones or my two speakers, one active receiver to each side of the phones.  On the antenna side I've simply connected both receiver inputs in parallel across my 50 ohm receiving antenna with no attempt at impedance matching or signal splitting.  It works just fine, and I notice no change in signal strength or ability to hear weak signals when I switch from listening on just one receiver (both rotary switches selecting the same receiver) to listening to two receivers.  I use 24 receivers at a time this way, all the way from a 1933 SW-3 to a 1950 HRO-50 to a 1968 Drake R4B.  It provides additional advantages in that I can hear an internal 100 kc calibrator from one of the receivers on another receiver that does not have a calibrator, and I can "spot" the frequency of my SW-3 regenerative set by listening for its oscillating detector on a paired superhet.  
An example of the KISS principle.
Jim, W8KGI

More information about the AMRadio mailing list

This page last updated 19 Feb 2018.