receiving antenna signal level tolerance

James Del Principe

I have just completed a K9AY loop for receive only on the low bands. While transmitting, I noticed the signal level displayed on the panadapter is bright white to red, indicating a very high signal level into the receive antenna. Of course, this would not happen using only an antenna on input 1 or input 2 which are switched during transmit. My concern is causing damage to my 6500 during transmit. I know there are ESD diodes for surge protection but I don't see that as a solution in this case. Short of creating a switch on the receive antenna coax to short the line during transmit, how do you handle this?  Is anyone else using a receive antenna and how do you deal with this?   Many Thanks, Jim         KD1I

K0FLY

I have K9AY loops as well as a DXE RX 4 Sq.   I also was  concerned about the signal levels at the RX antenna input.  I use a small 12 Volt relay to disconnect the K9AY loop when in transmit.  The relay (DPDT) is physically located near the FLEX radios and built in a plastic box like found on E-Bay, it  opens the coax center conductor and grounds the RX input when energized.    I use the  TX2 output to key the relay.  

I also key the +12 to the DXE array to disable the amps at the base of the verticals.

Gayle k0FLY

Bill -VA3WTB

Flex published a chart to help find the best distance the receive antenna should be seperated from the TX ant. In a safe distance considering power out would work.

James Del Principe

Gayle, I think you are right. I will need to construct a switch box with relay to do just that. Grounding the antenna and perhaps the Receive input should do the trick. Thanks for the reply. Jim

James Del Principe

Bill, I will look for that chart. I have the receiving loop away from the house but very near my OCFD..... not so good. Long term, I wanted to put a vertical up for 160/80 meters in the front yard, away from the house and other antennas. Thank you for the suggestion.   Jim