Topband: 4SQ Arrays in proximity

[Mpridesti]

I had heard several negative mentions of placing an 80 m system inside a 160 m 4 square.  At my place, I placed my 80 m 4 SQ northeast of my 160 m 4 SQ. Closest elements are 75 feet away. Thinking I might get some negative interaction, I took K3LR’s suggest of opening the feed points of the 80 m array while I am using 160. Built a relay box that shorted the cable ends (1/4 wave 75 ohm lines) so electrically opened the feed points. Pretty simple.  

Then spent a lot of time listening to WebSDR receivers in EU and switched that relay box on/off to see if I saw any gain variation with the 160 antenna. I saw no difference. However I have found a very slight improvement in F/B or F/S when the 80 m array was open circuited (shorting relays engaged). 

On the flip side of this, I have not seen any impact on 80 to the SW as I beam through the 160 array. I have reference antennas on each band to check array performance. 

I continue to experiment on 160 - fun retirement project with lots of exercise!

Seems array interaction varies with different stations.  I did not model my setup. 

Regards,

Mark, K1RX


> On Jan 28, 2020, at 10:47 AM, Tree <tree at kkn.net> wrote:
> 
> W7IV asks:
> 
> " --I am planning a 160m TX 4SQ and another for 80M.   Their centers are
> going to be about 300' apart - is this far enough away?  I have a little
> bit of room to move them apart, but am lucky enough as it is to have the
> space to get this.  The closest verticals will be about 200' apart."
> 
> My experience supports the post K9YC just made that you don't need to worry
> about this.
> 
> I used to have an 80 meter 4 square with my 160 meter TX antenna right in
> the middle of it and
> everything worked great.  You can also see this in the ON4UN antenna
> system.
> 
> 73 Tree N6TR
> 
>> On Tue, Jan 28, 2020 at 12:33 AM Paul F. Merrill <marinesvcs at gmail.com>
>> wrote:
>> 
>> HI - I have a couple questions -
>> 
>> --I am planning a 160m TX 4SQ and another for 80M.   Their centers are
>> going to be about 300' apart - is this far enough away?  I have a little
>> bit of room to move them apart, but am lucky enough as it is to have the
>> space to get this.  The closest verticals will be about 200' apart.
>> 
>> --I'll be using N6BT vertical dipoles, so there will be no radial issues.
>> 
>> --WRT TX chokes - I'm worried about constructing feedline chokes for the
>> feedpoints and still having enough cable (.85vf) to get to the phasing
>> box.  How have others done this?  Do you have a choke and did you add it to
>> pre-cut phasing lines or did you wind the chokes and work backwards towards
>> the center to get the required electrical or physical length?  Did you used
>> magnet wire for the choke instead of coax?
>> 
>> I've come across N6RO's helpful 2017 writeup of his 4SQ refurbishment and
>> it touches on these issues.  Anyone else have time to share some wisdom?
>> 
>> Thanks in advance, Paul / W7IV
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