[amsat-bb] Re: Please help me design a polarity switcher...

Greg D. ko6th_greg at hotmail.com
Wed Nov 4 20:32:05 PST 2009

Hi Elan,

The trick with doing circular polarization is the phasing of the two sets of elements.  Unless your two runs between the shack and the antennas are exactly the same length, and out of the same cable (for velocity factor matching), you're never going to get the result you want.

Others have posted information about the switching part; is there any way you can put that up on the tower?

Greg  KO6TH

> Date: Tue, 3 Nov 2009 21:24:59 -0800
> From: elanportnoy at yahoo.com
> To: amsat-bb at amsat.org
> Subject: [amsat-bb]  Please help me design a polarity switcher...
> I have both vertical and horizontal elements of my 70cm yagi coming into the shack via separate runs of LM400. They meet in a box with bits of coax for matching and phasing before going to the radio. 
> I would like to add a relay to make polarity changes quick and easy. Do I need to use a specific type of relay or will a garden variety DPDT from Radio Shack be sufficient?
> Thanks,
> Elan WB2IOL
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