[TowerTalk] 80m vertical ideas / questions

Jim Brown jim at audiosystemsgroup.com
Thu Dec 30 15:57:43 EST 2021


On 12/30/2021 2:00 AM, N1BUG wrote:
> So here is a question: Would 30 feet (real height 28 feet) of Rohn 25 be 
> OK freestanding with a 35 foot whip on top?

Hi Paul,

A quarter wave is a quarter wave electrically. The rest of it is all 
mechanical. A thin conductor (whip) on top is fine, because in a quarter 
wave antenna, most of the current is in the bottom half.

The other consideration is ground conductivity -- it is a MAJOR 
contributor to the performance of verticals, matters not at all for 
horizontally polarized antennas. If a vertical works on 160, a vertical 
will work on 80. AND -- it should be possible to load it on 80 with a 
suitable network.

Either way, a good radial system is needed to minimize ground losses, 
just like on 160. If matching the 160 vertical on 80, the 160 radials 
will be just fine on 80.

73, Jim K9YC


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