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*Subject*: [amsat-bb] phase shift with coax*From*: "Stan Vandiver" <Stan@xxxxxxxxxxxx>*Date*: Sun, 8 Jul 2001 20:00:32 -0000

Hi all, This is probably a no-brainer, but I will ask anyway. I'm needing to make a new phasing harness for a Cushcraft A144-20T to generate circular polarization. I have 2 of the 3 pieces that are original, and they seem to be somewhat shorter than I expect (about 10-5/8"). Is the "free space" formula for 1/4 wavelength (246 * velocity factor / freq in MHz) = length in feet) the correct way to calculate the lengths for these pieces? Do I need to factor in a little length to account for the barrel connector between the parallel phasing line and the delay line? Or account for the "T" connector that splits to the horizontal and vertical sections of this beam? The connectors might explain why the Cushcraft pieces seem a little short. But also I do not know the velocity factor of the coax that they used, so I'm kinda confused on how to replace them. I'm thinking of replacing all of them, but maybe the better choice would be to just make one to replace the missing piece (which is one of the RG-59 75-ohm legs)? Will there be any good way for me to judge the effectiveness of the circular pattern.... or is SWR the only measurement I can make? Your comments are welcome! 73 de Stan/W4SV ---- Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA. To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org

**Follow-Ups**:**Re: phase shift with coax***From:*John Stephensen, KD6OZH

**R: phase shift with coax***From:*i8cvs

**Re: phase shift with coax***From:*Vince Fiscus, KB7ADL

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