Replacing the Beverage feeding system

I’m replacing my Beverage feeding system. The relays in the switchbox was powered through the feeder which was 40 m of buried RG-6 coax plus 70 m of military phone line in the trees. I had problems with noise from the relay voltages so now replacing it with buried outdoor UTP cable feeding the relays separated from the RF feeder.

The impedance of a UTP pair is 100 ohms and measured attenuation over 100 meters was as follows:

1.8 MHz                1.5 dBs

3.5 MHz                1.7 dBs

10.1 MHz             2.6 dBs

I took the transformers from the old 70 ohm system and measured the 50 ohm SWR all the way through 100 m UTP to a 560 ohm resistor in place of the Beverage wire:

The SWR was 1.35 at 1.8 MHz, 1.05 at 3.5 MHz and 1.55 at 10.1 MHz


Today Oct 4, the new beverage feeding system is up-and-running. Works as expected but the ground lead is too long picking up too much signal, especially on 40 and up. Had to move the relay unit from one tree to another. Will try to improve that.