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Frontshadow
New member
Username: Frontshadow
Post Number: 2
Registered: 2-2016
| | Posted on Tuesday, March 01, 2016 - 3:03 pm: | 
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I just received my Maco Comet....planning on putting it up in a month or so. As you may know, the Comet is both vertical and horizontal polarized. I'm going to install a balum just under the feed point for both horizontal and vertical. Am starting with 7 turns coax, on a 6" diameter.
I'm wondering of the actual positioning (where mounted on the tower-antenna mast) would matter since there are two, AND (more interesting), what would happen when I run as CIRCULAR polarization.
Anyone...? |
Tech833
Moderator
Username: Tech833
Post Number: 2350
Registered: 8-2002
| | Posted on Saturday, March 05, 2016 - 5:36 pm: |
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A balun made from turns of coax is a common mode choke, not a balun. People (particularly hams) confuse that all the time.
Anyway, if your goal is to reduce common mode currents on the coax, then you want the choke to be as close to the feedpoint as possible.
As for running 'circular' polarization... That will only happen if your feedpoints are 180 degrees out of phase (90 degrees in physical world). If they are fed with equal lengths of coax, it will not be circular. It will be dual polarity with half the power on each.
Your radio 'Mythbuster' since 1998
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