Bill, I measured the new low-split Sinclair harness before installing it, and found that the distance between the centers of the tees was exactly 14". The length of the loop inside the cavity is about 8.5", and this length must be considered when performing the calculations. My guess is that a distance of 15.9 inches between harness tee centers will result in a tuning in the 125-130 MHz range. Did you consider the loop length in your calculations?
Your comment about the cable on your duplexer being single-shielded RG-213 got me wondering. Sure enough, the cable I pulled off the club's Q202-G duplexer was RG-213, but the new harness was RG-214. I have another Q202-G duplexer that has the original high-split harness on it, and it is RG-214. I guess Sinclair wised up to the leakage issue... 73, Eric Lemmon WB6FLY -----Original Message----- From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of Bill Photinos Sent: Wednesday, December 26, 2007 8:48 AM To: [email protected] Subject: Re: [Repeater-Builder] Sinclair Q202G duplexer Conversion Thanks to all who have replied. You have been a great help. Have calculated the harness length for my freqs to be ~15.9" when taking into account the velocity factor of the interconnect cable etc. Believe it or not the original cable on our cans is RG-213 and not RG-214. We are replacing with high quality double shielded(100%) cable. FYI the harness is currently $311 from Sinclair. It will ending up costing us around $100 in parts to assemble our own harness. Significant difference. Hope to have it completed and up on our DSTAR repeater in a couple of days or so. Thanks again & 73s Bill - W4RVN Eric Lemmon wrote: Steve, That trick works fine for offsetting the harness tee from the loop assembly in the can, but it doesn't do a thing for increasing the spacing between the tees. The later-design Sinclair Q202-G duplexers come with a one-piece harness that is made up from sections of RG-214/U cable with five crimped-on N tees and two crimped-on straight N plugs. The tees are made by Delta Electronics, and are intended for one-time, permanent installation. Even if great care is used in cutting off the ferrules, it is very easy to damage the tee during the process. Although it is time-consuming to dismantle the high-split harness and re-build it with longer cable sections between the tees, the club chose to buy the harness from Sinclair. It cost about $125 five years ago. Once the new harness was installed, the Q202-G duplexer tuned up perfectly in the 2m band. 73, Eric Lemmon WB6FLY -----Original Message----- From: [email protected] <mailto:[email protected]> [mailto:[email protected] <mailto:[email protected]> ] On Behalf Of Steve S. Bosshard (NU5D) Sent: Wednesday, December 26, 2007 1:06 AM To: [email protected] <mailto:[email protected]> Subject: Re: [Repeater-Builder] Sinclair Q202G duplexer Conversion When I moved some 155 mhz duplexers to 146 I found adding a type n elbow in places where I could not get the notch to move made just enough difference. This adds about an inch without having to rebuild the harness, or else a nice way to test cable lengths. Also if adding the elbow makes things worse, then you might want to cut and try. 73, Steve NU5D
