This is a scenario where the use of a VNA/VNWA can be helpful. Attach one port
to one of the tribanders, the second to the other, then you can plot return
loss between the two. Yes, even one of the popular hand-held devices can
accomplish this. Set each in a direction, then test. Repeat at different
directions until you have enough plots to tell you how much interplay you will
get, and then know which directions to avoid. This method is incredibly useful
when trying to determine how much filtering you need for bands/antennas in an
SO2R environment, but is also useful for antennas on the same bands.
This will not tell you how the signals will mix and match. For that be sure to
follow Gary’s usually excellent advice!
73,
Jack, W6FB
> On Feb 3, 2026, at 1:36 PM, Gary Johnson via TowerTalk
> <[email protected]> wrote:
>
> The pattern can get kinda strange when Yagis on separate towers are both
> driven. Odd lobes and nulls depend on pointing and may not be intuitive.
> AC6LA has an example generated with AutoEZ. YMMV. Simulation advised.
> https://ac6la.com/aecollection5.html#:~:text=have on hand.-,Coupled Yagis on
> Separate Towers,-A question was
> <https://ac6la.com/aecollection5.html#:~:text=have%20on%20hand.-,Coupled%20Yagis%20on%20Separate%20Towers,-A%20question%20was>
>
> -Gary NA6O
>
>>
>> Subject: [TowerTalk] Tribanders on separate towers
>>
>> Hello Towertalk
>>
>> I?ve been considering installing multiple triband Yagis (interlaced element
>> types, say 4/4/8) at my QTH to be able to switch directions quickly or power
>> split in multiple directions. Installation heights can be between 50-120?
>> and the towers are between 100-200? apart. Some time ago ISTR Frank W3LPL
>> saying this arrangement would need careful modelling (maybe it was on a CTU
>> presentation) but I?ve not been able to find this information since.
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> [email protected]
> http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
[email protected]
http://lists.contesting.com/mailman/listinfo/towertalk
|