I have had for about 20 years 160 m four square and 80m four square inside.
There is in center 50 high tower and both antennas are of wire elements with
elevated radials. 160 directions are North East, South East, South West and
North West. 80m elements are turned 45 degrees; North, East, South and West.
160 meters works very well with about 15dB F/B and sometimes more. 80 meters is
not that good F/B is about 10dB.
All elements are connected all the time to couplers.
I do see my 80m antenna is good in performance anyway as here is a clear
interaction to 160m antenna.
I have not used modelling or carried out any precise measurements of
performance of these antennas.
73
Ilmo, OH2BO
-----Alkuperäinen viesti-----
Lähettäjä: Topband
[mailto:topband-bounces+ilmo.anttila=qualisys.fi@contesting.com] Puolesta Jan
Erik Holm
Lähetetty: 28. tammikuutata 2020 20:29
Vastaanottaja: topband@contesting.com
Aihe: Re: Topband: 4SQ Arrays in proximity
I once was thinking about a deal like this. In my case I wanted
to put a 40m 4SQ inside my 80m 4SQ.
I did model it and saw a slight gain loss, think it was just
around 1 dB or so. I didn´t like that so I instead did put
the 40m 4SQ 300m/1000ft away from the 80m array. I´m sure
I could have bettered the situation by detune the 80m
antennas but I never did look in to that.
Gain loss was on the 40m array, the 80m didn´t get hurt.
/ Jim SM2EKM
Den 2020-01-28 kl. 17:43, skrev Mpridesti via Topband:
> 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@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@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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