Bruce, What is the model number of the Sinclair combiner you wish to modify? Some of the Res-Lok combiners have machined slots between the cavities, and some do not. Have you contacted Sinclair tech support about performing this conversion? It may be better to ship the combiner back to Sinclair for the conversion. Be aware that, due to the relatively small volume of the Res-Lok duplexers, a converted combiner may not be satisfactory for the 600 kHz split used on 2m repeaters.
73, Eric Lemmon WB6FLY -----Original Message----- From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of lpcoates Sent: Saturday, September 15, 2007 8:20 PM To: [email protected] Subject: [Repeater-Builder] Sinclair duplexer notches Hi I'm helping a friend who wants to convert a Sinclair Res-Lok 4 cavity combiner into a duplexer. Basically turning it into a Q2220E I think). As far as I can tell, it should be possible by simply adding a variable cap to the coupling loops. I still haven't found the answers to to two questions. 1. What is the correct length of cable between each cavity? 1/4 wavelength? 1/2 wavelength? Something else? 2. What determines the location of the notch? two cavities will have the notch above the pass band and the other two will have the notch below the pass band. I suspect there's something different about the coupling loops but I don't know what. Thanks Bruce VE5BNC
