[TowerTalk] Isolating adjacent 4-Squares

K9MA k9ma at sdellington.us
Mon Dec 21 11:33:05 EST 2020

The interactions, based on my modeling, usually affects the nulls in the 
pattern much more than the forward gain. This is mainly a concern for 

Scott K9MA

On 12/21/2020 7:05 AM, john at kk9a.com wrote:
> Did you model this before building it?  From the little bit of 
> vertical array modeling that I have done I found the patterns easily 
> skewed by other verticals and towers, even those pretty far way. You 
> may have been better off centering the 160m 4Sq around the 80m one.
> John KK9A
> Charles N1RR wrote:
> I have an 80M wire 4-square around tower #1. (90ft with two big 10M & 15M
> monobanders) Each vertical has 12 above ground radials and is tuned to
> 3535. All guys are broken with insulators.
> This array works well.
> My second version of a 160M wire 4-square around tower #1 was raised last
> week. They are Inverted L's  to a 120ft tower. It already has two 
> Cushcraft
> 40-2CD's and a big homebrew 20M6L OWA yagi. All guys are broken with
> insulators. Each Inverted L has 20 on-ground radials and is tuned to 
> 1725.
> The closest 80M element is 40 feet from a 160M element.
> The 160 is not working well. I will be testing the phasing lines once 
> this
> snow melts. ###
> I want to apply a passive device to further isolate these systems. I'm
> thinking of a 1/4 wave 50 ohm shorted coaxial stub on each feedpoint. My
> first guess is the 160 elements.... ?
> Alternatives are to move one of the arrays.... but I'd rather explore
> making them work where they are.
> -Charlie N1RR
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Scott  K9MA

k9ma at sdellington.us

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