Tom, I looked at some loop assemblies from a Sinclair Q202G duplexer, and found that all of the variable capacitors are stamped Johanson #5602. That capacitor is rated at 1 to 30 pF, shown on page 4 of this catalog sheet:
<www.johansonmfg.com/Catalog/Air%20Capacitor.pdf> I could not identify your part #MAV05A30, but I suspect that it is a 5-30 pF capacitor made by another company. Perhaps the previous owner was attempting to re-tune that duplexer to operate in the Amateur 2m band from a commercial pair, and did not realize that the cable harness *must* be changed for the duplexer to meet specs on 2m. There is no difference in the loops between the two band splits (138-150 and 150-174 MHz). 73, Eric Lemmon WB6FLY -----Original Message----- From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of tomnevue Sent: Wednesday, April 04, 2007 11:29 AM To: [email protected] Subject: [Repeater-Builder] Duplexer cavity repair I bought a Sinclair Q202G 4 can VHF duplexer. The previous owner clearly spent a lot of time playing with the variable capacitors. 2 are totally ruined and I suspect the other 2 are damaged because I can't get a notch depth below 60dB and it's not stable. These are porcelain (white glass) piston style marked MAV05A30. Can anyone help me with some replacements or source of supply? Any help is appreciated. Tom W2MN
