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Re: Topband: dipole height

To: "Bob Kupps" <n6bk@yahoo.com>, "topband" <topband@contesting.com>
Subject: Re: Topband: dipole height
From: "Tom W8JI" <w8ji@w8ji.com>
Reply-to: Tom W8JI <w8ji@w8ji.com>
Date: Tue, 30 Oct 2012 16:08:51 -0400
List-post: <topband@contesting.com">mailto:topband@contesting.com>
Hi it's an interesting discussion about the dipoles. I want to put up an inverted vee dipole for 160. I can put the apex at 15,30,45 or 60m and have >90 degree apex angle. The ground is very good and I am right on the magnetic equator. >>>

I'm sure what works here is different for you, but I never saw much difference at sunrise peaks between various dipoles at different heights....and my antennas were hundreds of feet apart and tuned to avoid interaction. My really high dipole had a decided advantage over low dipoles at off-peak times, but never was better than a modest vertical. My high dipole was a toss up with low dipoles during peaks or aurora, and with the vertical.

An inverted Vee dipole has a pattern almost like a regular dipole with legs much >90 degrees. It just has a little less null off the ends (where pattern is tilted to nearly vertically polarized). An inverted Vee dipole is pretty much like any dipole except at slightly lower effective height, the main difference is less end null.

I can't imagine any performance advantage to a dipole intentionally lower than 45 meters on 160 meters, let alone an inverted Vee dipole. The pattern does not change significantly at useful angles over that height range, except for increased losses at lowest heights.

The biggest differences would be between a vertically polarized antenna and a dipole, not between various dipoles all below 1/4 wave effective height. It isn't like you can have a dipole with high angle suppression or low angle enhancement when they are that low. I'd just put up the highest one you can manage.

73 Tom
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