wpp3 wrote: > 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?
That is the proper formula but don't get too hung up on exact lengths. > > 2. Are the lengths exactly the same for the low and the high sides or > are they dependent on individual frequency for each side. The lengths are not highly critical. AFAIK Sinclair only had 2 standard harnesses, one for the low part of the band and one for the high part. The low split harness cables were about 1 inch longer each. > > 3. Where is the measurement taken? From tip-to-tip of cable or from > center-of-T to center-of-T, etc? Between center of Tees. > > 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? Maybe or maybe not the length of the cables. However anything that will lengthen the distance between the center of the Tee and the loop will affect the tuning and depth of the notches. Now the key question. Why would anyone want to use a pitifully inadequate so-called UHF adapter or connector on a well designed system that is intended to have N type connectors. Throw out all your UHF connectors and adaptors and go with the proper type N connectors. Save yourself a lot a hassle later with problems related to the UHF connector series. That is just my opinion based on past experience. Others may differ. Burt VE2BMQ
