Hi all, I have built a simple polarity control box to allow V, H, RHCP & LHCP off my 6 element homebrew crossed yagi. The yagi had an SWR of 1.1 to 1 on 145mhz on the 45degree and 135degree elements, so they are fine. The control box is a copy off the G6LVB website and the VHF/UHF manual 4th edition. The unit is basically 2 x 1/4waves of 75ohm coax to use as a matching unit and then relays to switch in or out 1/4 wave and a 1/2wavelength of 50ohm coax to give the different polarities. My small problem is although the SWR through all the modes is under 1.5 to 1 I would like to bring it down a little, but is it worth the effort? results: V polarity 144mhz 1.2 to 1, 145mhz 1.3 to 1, 146mhz 1.5 to 1 H polarity 144mhz 1.5 to 1, 145mhz 1.3 to 1, 146mhz 1.2 to 1 RHCP 144mhz 1.1 to 1, 145mhz 1.3 to 1, 146mhz 1.5 to 1 LHCP 144mhz 1.5 to 1, 145mhz 1.3 to 1, 146mhz 1.1 to
Am I worrying over nothing or should I go and alter the unit to give a slightly better result, my head says 'leave lt alone or you will muck it up'. But I am also thinking a little shorter cable might be all it needs? Does anyone know by looking at the figures what cable needs to be altered (longer/shorter). Thanks for any advice regards Gus M0IKB