Collin, it depends on what vintage Q-202G you have. I have four duplexers that have the rexolite rod caps to adjust the notch frequency on each cavity, and I brought them down into the ham band by increasing the length of the jumper cable that connects directly to the cavity from 10.5 inches to 12.5 inches.
I also came up with a manual and Eric Lemmon scanned it into a PDF file and posted the manual on the repeater-builder site. http://www.repeater-builder.com/sinclair/q202-208-218-tuning.pdf The manual explains how to tune the duplexer to a new frequency. What you have to keep in mind is that the first piece of cable connecting to each cavity is part of the notch circuit and that piece of cable in conjunction with the variable setting of the dialectric rod determines the frequency of the notch. Also keep in mind that this circuit produces a notch above and below the center frequency the cavity is tuned to, and the high and low sides of the duplexer have identical circuitry. 73 - Jim W5ZIT [EMAIL PROTECTED] wrote: Dear Friends, I am working on retuning a Sinclair Q-202G duplexer to 144.810/145.410. The question I have is about the new cables I will need. First will I need all new cables? What I mean is there are actually eight pieces in all. These need to be 1/4 wave each? Also when measuring these I know the measurement is from the center of the "T" connector. When measuring to a connection on a stub where is the measurement taken from? I have some RG-213 cables which measure 12" from "T" center to "T" center. Anyone that can help would be greatly appreciated. Thanks, Collin --------------------------------- Never miss a thing. Make Yahoo your homepage.
