Bill, This topic has been addressed several times in recent years. There is no "formula" for the harness; Sinclair makes two harnesses, one with 12" between tees, and another (for the 136-150 MHz split) with 14" between tees. The coupling loops are identical between splits; the harness is the only difference. The harness is completely symmetrical.
It may be easier to simply purchase the correct low-split harness from Sinclair, for about $150. The harness is fabricate with Delta crimped tee connectors. 73, Eric Lemmon WB6FLY -----Original Message----- From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of wpp3 Sent: Tuesday, December 25, 2007 12:35 PM To: [email protected] Subject: [Repeater-Builder] Sinclair Q202G duplexer Conversion Read the posts here already and wish to clarify a few things. First I am in the process of converting a Q202G from the 160mhz range down into the 2m band, specifically 144.7500/145.3500Mhz. I have found that I will need to replace the harness to do this as it will not tune down that far. 1. I Understand I must make the harnesses at 1/4 wavelength each between the cavities and from the cavities to the antenna "T" connector. What is the formula for the exact cable length? i.e. 1/4 wavelength of freq * velocity factor of cable = cable segment length? 2. Are the lengths exactly the same for the low and the high sides or are they dependent on individual frequency for each side. 3. Where is the measurement taken? From tip-to-tip of cable or from center-of-T to center-of-T, etc? 4. In relation to #3 I will be using a N-Male/UHF-Female adapter on each can. Then connecting the "T" to that adapter. Will this affect the cable harness length calculations and if so how? Thanks in advance! Best Regards, Bill - W4RVN
