Yeah, it does get a bit complex with the phasing stubs and impedance transformers, the need for coax of an odd impedance (70 ohms which doesn't exist, so 75 ohms used as a compromise), etc.
That's why I advocated using a 2-port power divider, a device which physically acts as the impedance transformer needed to connect two 50 ohm antennas in parallel and remain at 50 ohms to the radio connection. And if the "mechanical method" of getting the quarter wave offset between elements is used, then no need to get coax feeders of different lengths by exactly a quarter-wave after adjusting for velocity factor. Just two pieces of 50 ohm coax of exactly the same length, which can be easily verified with relatively simple test equipment, namely a dual-channel oscilloscope with x-y plotting mode.
On Fri, Feb 10, 2017 at 8:28 PM, Kevin M via AMSAT-BB [email protected] wrote:
You may find this page very useful... I don't understand it all, but it sure educated me: http://www.qsl.net/sv1bsx/antenna-pol/polarization.html
73, Kevin N4UFO
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