> 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 > nfound both at reasonable prices at this site:
A generic statement that has merit in this subject "Q is everything" and the Q of an Arco cap ("padder") is probably no where near as good as a decent piston cap. Ebay provides the occasional deal on nice piston caps. If you're not at a critical current location, the A49 piston caps in the following sale ad work for some applications. http://www.hamtronics.com/sale.htm s. > http://www.danssmallpartsandkits.net/ > > 73 and aloha, Eric KH6CQ > > --- On Sun, 6/27/10, Tim <tahr...@...> wrote: > > From: Tim <tahr...@...> > Subject: [Repeater-Builder] Piston Trimmer Voltage Rating > To: Repeater-Builder@yahoogroups.com > Date: Sunday, June 27, 2010, 11:18 AM > > > > > > > > Â > > > > > > > > > > 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 >