Jim, Sinclair makes two harness assemblies for that duplexer. The jumpers are about two inches longer in the low-range harness, and that makes a world of difference. You can order the low-split harness directly from Sinclair. Go to: www.sinctech.com Make it very clear that you want the "low range" harness, as some of the Sinclair sales folk seemed to be unaware of its availability, the last time I called them. A year or so ago, that harness cost about $145. It's all in one piece, with crimped connections. As I recall, the low range was for 136-150 MHz, and the high range was for 150-174 MHz.
Most Bp/Br cavities will have one notch above and one notch below the pass frequency. I have tuned several Sinclair duplexers of this design, and they all tuned up perfectly once the correct harness was installed. 73, Eric Lemmon WB6FLY -----Original Message----- From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of Jim Brown Sent: Saturday, April 22, 2006 2:10 PM To: [email protected] Subject: [Repeater-Builder] Sinclair Q 202G Tuning Problem I am trying to move a Q-202G from the 170 MHz range down to the 147 MHz range and have run into a problem on the notch tuning. The high pass tuning works like a charm and has a good pass and notch characteristic. The low pass side is another story. The pass tuning works fine, but I can't get a notch. With the tuning rods all the way in, it is starting to notch, but only about 20 db. Here is the strange thing - I took the coupling loop out of the high pass side and compared it to the low pass side, and they are identical. The tuning rod varies the capacitance across the single loop connector and there is no inductance in the circuit for either high pass or low pass side. How does the same hookup work to allow a notch on the low side as well as the high side? I am tempted to add a small fixed capacitance across the loop to see if that helps the tuning for the low pass side.. Any comments on which way to go? 73 - Jim W5ZIT Yahoo! Groups Links Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ <*> To unsubscribe from this group, send an email to: [EMAIL PROTECTED] <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
