----- Original Message ----- From: "Tim Goodrich" [email protected] To: [email protected] Sent: Sunday, October 11, 2009 10:51 PM Subject: [amsat-bb] accidental RF into wrong cable of Arrow=bad duplexer?

I am an owner of a 2m/70cm LEO satellite antenna with duplexer in the handle. Sometimes, I operate full duplex (two radios) and bypass the duplexer by attaching my own cables to the separate parts of the antenna

(1

radio for 2m, 1 radio for 70cm). In the course of rushing to catch a satellite pass, I mixed up my connections and accidentally transmitted (5 watts) into one of the arrow antenna cables, causing RF to feed backwards into the duplexer.

Recently, I have noticed decreased performance (poor reception, lower

S/N,

even on AO-51 when in the past it was full quieting) and am trying to ascertain if it could have anything to do with my mistake of feeding RF in the wrong direction into the duplexer. Could my mistake cause this

problem?

Thanks,

Tim

KI6VBY

Hi Tim, KI6VBY

If I well understand you connected the VHF antenna to the UHF connector of your duplexer and the UHF antenna to the VHF connector of your duplexer while transmitting by mistake.

A duplexer is essentially a low-pass filter at VHF and a high-pass filter at UHF having in the middle the common connector going to a VHF/UHF tranceiver.

If you reverse the antennas at the output of the above duplexer the only effect will be a very high VSWR in both bands VHF and UHF but no damage will involve the receivers.

Best 73" de

i8CVS Domenico