Norm, Good catch on the tuning caps- they're not indestructible. You lucked out on finding a suitable replacement tuning cap in an ICOM. As for the photos, perhaps you could post them in the Group Photos section for all to see. I want to see the photos, but my experience with Sinclair products is somewhat limited.
73, Eric Lemmon WB6FLY -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of NORM KNAPP Sent: Tuesday, August 11, 2009 4:16 AM To: [email protected] Subject: Re: [Repeater-Builder] Update, Sinclair Q-202G (Frankenstein series) Hi Eric The harness is as close to exactly the right lenght as I could possibly make the lenghts. I replaced the RG-142/U jumpers (which were probably the right lengths as well) with RG-214/u . I was told to make them so that there was 14" between centers of the "T's". I then started with an Anritsu sitemaster on the high pass cans and set the pass adjustment useing the return loss sweep. I then used my Areoflex to set the notches. Everything went smooth as silk. I then swithed over to the low pass side. The pass tuned, no problem. When I went to tune the notches, I found that one of the caps was almost as far up as it would go and the the other one would not quite get the notch to where I wanted it. I then started playing with turning the coupling loops. Of course, that didn't do any good. I then decided to pull the loops for a look. When I did, I discovered that there was a 12pf silver mica soldered in paralell with the Johanson tuning cap on both the loops. Also, one of the loops was made of sliver plated copper and "looked" factory and the other was copper and did not "look" factory. The way the copper one was shaped and bent made it appear "homemade". I took the 12pf caps off of the tuning caps and tried to set the notches again, this time I had to go all the way down, and the notch was still not quite right. I then took the loops back out and soldered a 5pf cap accross the tuning caps. This worked great on the factory loop, but the other one wouldn't tune at all. What happed? I took the loop back out and I decided to reshape and bend the loop to look like the silver plated "factory looking" loop. That didn't help. Still no tune... Hmmmm... What gives here? I took the loop back out again and quickly discoverd that I had somehow overheated the tuning cap and destroyed it. To make the long story short, I ended up taking a tuning cap from an EC vhf ICOM I had lying around and putting a 12pf cap accross it to get the adjustment range I wanted. It appears to be working well for now, but I have not pulled either of the high pass loops to see what is different about them. I have a set of Q-202GR duplexers with the sliding rods that I just replaced all the RG-213/u with RG-214/u with corrected lenghts for 2m that I am going to swap out temporaraly so I can try to get the right cap installed in that on can and to find out what is different about thos high pass cans. The repeater is 23.5 miles from my house and just don't get to go out there as often as I would like. By the way Eric, I have a set of sinclair duplexers that I cannot identify. Can I send you a photo or two to your e-mail? Thanks es 73. De N5NPO Norm ----- Original Message ----- From: [email protected] <mailto:Repeater-Builder%40yahoogroups.com> <[email protected] <mailto:Repeater-Builder%40yahoogroups.com> > To: [email protected] <mailto:Repeater-Builder%40yahoogroups.com> <[email protected] <mailto:Repeater-Builder%40yahoogroups.com> > Sent: Mon Aug 10 20:55:26 2009 Subject: RE: [Repeater-Builder] Update, Sinclair Q-202G (Frankenstein series) Norm, I'm glad that you're getting that duplexer working. But, I am curious about those parallel capacitors. None of the factory-tuned Sinclair Q-202G duplexers I've seen had any capacitor in parallel with the Johanson tuning capacitors- even those made for the 2m band. The loop assemblies for the high-pass and low-pass cans are identical. Perhaps the previous owner added capacitors because the tuning caps were damaged. Or maybe the loop assemblies for a combiner were used in place of the correct BpBr loops. Are the interconnecting cables the correct length? 73, Eric Lemmon WB6FLY -----Original Message----- From: [email protected] <mailto:Repeater-Builder%40yahoogroups.com> <mailto:Repeater-Builder%40yahoogroups.com> [mailto:[email protected] <mailto:Repeater-Builder%40yahoogroups.com> <mailto:Repeater-Builder%40yahoogroups.com> ] On Behalf Of NORM KNAPP Sent: Monday, August 10, 2009 6:35 PM To: [email protected] <mailto:Repeater-Builder%40yahoogroups.com> <mailto:Repeater-Builder%40yahoogroups.com> Subject: [Repeater-Builder] Update, Sinclair Q-202G (Frankenstein series) I talked to the guy that obtained the duplxers for our club and he confirmed my belief. Those 4 cans began life as 4 separate BpBr filters used on some offshore communications, possibly mobile telephone or phone patch. He was not certain. Anyway the high pass side worked great out of the box so to speak, but the lo pass was a booger. I had to change the parralell cap values on the tuning caps for the notches. I still don't have quite as good a notch as I have on the high pass pair, but it works well anyway. 73 de N5NPO Norm
