I recall a problem with a UHF repeater with terrible desense that I had some 30 years ago. The original installer didn't have an N connector for the pigtail and used an N to BNC female adapter and stuck one wire of the RG8 in the center hole and soldered the braid to the outside. Needless to say it didn't work. Replacing that thing (which I still have) corrected the problem and it ended its service life with my repair.
Steve KB3FPN ----- Original Message ----- From: Ken Arck To: Repeater-Builder@yahoogroups.com Sent: Saturday, April 19, 2008 8:51 PM Subject: [Repeater-Builder] Bad adapter Just thought I'd share this with everyone in case you face the same thing. My 2 meter machine started experiencing noticeable desense about a week ago. No real serious weather had occurred during this time, just the usual Oregon rain. As I had replaced the antenna and hardline about 2 months ago, my first thought was water infiltration. I went to the site this afternoon (can you believe it was snowing in April? - Damn that global warming!) and the first thing I did was check VSWR between the duplexer and hardline feed to the antenna. 60 watts forward, zero reflected. Whew, it's probably not the antenna or hardline (no fun when you're dealing with an almost 200 foot tower). The next step was to check the VSWR between the duplexer and PA. Cool, 90 watts forward, < 1 reflected. Hmmmm, the desense is still there. Ok, back to the duplexer output "just in case". Still the same - no reflected power but wait! The desense is gone! So what was different between no Bird and the Bird in line? As it turned out, it was an SO239 to N adapter that I had used because I didn't have the proper stinger with me when we replaced the hardline. The adapter is used between the stinger (which has a PL239 on one end) and the duplexer, which is an N. And while the adapter was a genuine Amphenol (silver plated and everything), I found out when I got home that the center conductor connection was only crimped and that center conductor was cracked. Placing the Bird in line required not using the adapter so voila! I used another adapter I had with me and the repeater is working great again. You better believe I'm headed back up to tomorrow with a proper stinger with N connectors! Pics are here: http://www.arcomcontrollers.com/connector1.jpg http://www.arcomcontrollers.com/connector2.jpg Even quality can fail! Ken ---------------------------------------------------------- "The American people will never knowingly adopt socialism, but under the name of liberalism they will adopt every fragment of the socialist program until one day America will be a socialist nation without ever knowing how it happened." --Norman Thomas, Socialist Party presidential candidate 1936- 68, Cofounder of the American Civil Liberties Union
