[TowerTalk] Greyline Performance antennas

[Kim Elmore]

This is gold, Jim. Thanks much for sharing!

Kim N5OP

On 10/17/2020 5:15 PM, Jim Brown wrote:
> On 10/17/2020 1:24 PM, Kim Elmore wrote:
>> Maybe I should have said "... making sure it has a good CM choke," 
>> especially since you've taught us how to make them! Even if the feed 
>> is in the center (it could be if the transmission line is run up the 
>> bottom half) it still won't be balanced. A CM choke is always needed. 
>> I've become convinced that balanced antennas make analysis much 
>> easier (even possible) but that in the real world, there aren't any.  
>> I have no idea what the electrical length is for 6 m or even 10 m, so 
>> the low radiation-angle assumption might be invalid on those bands.
>
> Here are slides for a talk I gave on the Pacificon Antenna Forum 
> several years ago on an 80M vertical dipole for our 7QP and CQP 
> expeditions, based on N6BT's design ideas. Yes, it does need a serious 
> choke were the coax feeds up through the tubing to the feedpoint.
>
> http://k9yc.com/80M-FDVertical.pdf
>
> Testing it in Glen's pasture showed it to significantly outperform an 
> inverted Vee with the center at 46 ft, but mechanical issues with the 
> design caused us to abandon it after modeling and building several 
> alternative designs.
>
> 73, Jim K9YC
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-- 

Kim Elmore, Ph.D. (Adj. Assoc. Prof., OU School of Meteorology, CCM, PP 
SEL/MEL/Glider, N5OP, 2nd Class Radiotelegraph, GROL)

/"A great second violinist plays second fiddle to no one." //– Robert C. 
Marsh, Chicago Sun-Times./