Instead of piston trimmers you might want to try ARCO padders (postage stamp size that can tolerate higher levels of rf current) or small air variable capacitors. I have found both at reasonable prices at this site:
http://www.danssmallpartsandkits.net/ 73 and aloha, Eric KH6CQ --- On Sun, 6/27/10, Tim <[email protected]> wrote: From: Tim <[email protected]> Subject: [Repeater-Builder] Piston Trimmer Voltage Rating To: [email protected] Date: Sunday, June 27, 2010, 11:18 AM Hi folks, Am just finishing up the 6 meter heliax duplexer project, and am getting some pretty good numbers. (3 'cans' on each side, >90dB notch & about 1.2dB 'pass' attenuation).. Anyhow, I used some Johanson piston trimmers that I had, but evidently they are a bit shy on the working voltage rating, as the one closest to the transmitter (80 w, @53.15) didn't quite cut the mustard! A nice arc hole in the piston. Anyhow, was wondering what the working voltage is for these guys. Guess I need to look around for some substitutes. Thanks, Tim W5FN Utopia, TX
