Yo Tree
Never used a gamma matched tower so I'm just an observer here.
We did have this discussion on the reflector, maybe before the
archive started but some were convincing that you can't do it
and Earl, K6SE said you could.
My feeling is anything is possible with the right test equipment and
you can phase any loads using a hybrid but series fed monopoles
are easy and trivial while gamma matched towers will have the
"third" knob problem.
When I built this 1/4 wave vertical I did the model as it went up
and the results was always about ten feet ahead of the real antenna
resonance point using a radio at the base of the tower and 100
watts. Local BC made the MFJ useless. BC can disturb your test
equipment and until you get a good handle on your soil conductivity
any software model might be of little value. Plus stack antennas all
moving around on the towers, in line or not??(does this matter), etc.
I have been following your experiments over the years and hope
you give this a shot. We all might learn something for topband
station building.
73 Rich KL7RA
p.s. I am not moving to 1.996 MHz even if it is better, sorry.
----- Original Message -----
From: "Tree" <tree@kkn.net>
To: <topband@contesting.com>
Sent: Wednesday, July 15, 2009 7:10 AM
Subject: Topband: Two element phased array
>
> We all know summer months are designed to give you a break from the action
> on 160 meters - so that you can improve your antennas for next season.
>
> After some consideration - I have decided to try a phased array of two
> verticals instead of continuing my testing with parasitic wires.
>
> Some of the factors that influence my decision are:
>
> 1. Phased array has excellent F/B over a wide frequency range. This will
> be a useful antenna in the second receiver (using a K3 in diversity mode).
>
> 2. A bidirectional pattern to the east coast and JA is very useful during
> contests.
>
> My current vertical is a gamma matched tower - and I am worried about how
> that phasing works with that. However, I have decided to put up a second
> tower that I estimate will have the same electrical height - and will
> hopefully be well matched with an identical gamma match. This sould
> minimize any variability and hopefully result in a well matched system.
>
> I will be using a hybrid coupler to get my 90 degree phase shift - and
> a simple transformmer to match the impedance when the two verticals are
> in phase. The towers are spaced 1/4 wave apart and in line north/south.
>
> If any of you have some practical experience with something similar, I
> would love to hear your comments. I remember visiting K6SE back in the
> 1970's and his system worked very well with two gamma matched towers.
>
> 73 Tree N6TR/7
> Boring, OR
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