[TowerTalk] Feeding one antenna in a stack
K3BU at aol.com
K3BU at aol.com
Sat May 31 20:56:14 EDT 2003
In a message dated 5/31/03 8:03:25 AM Eastern Daylight Time,
n4zr at contesting.com writes:
> My 4-element lazy-vee array is also built this way, in a plastic box, with
> both the shields and the center conductors floated. I did it this way,
> even though it is a pain in the neck, because it's what K3LR said one
> should do, but don't understand the theory. I would have thought that an
> open stub with its shield grounded at the open end and connected to the
> shields of other similar stubs would still have functioned as an open
> but don't know. Can anyone explain?
I think that was the result of our verbal barrage at the time. One thing is
to claim certain performance (theoretical ?), another thing is to see the
results and measure it. Even using current baluns did not help.
Looks like we have a case with wires in the RF fields, lengths close to 1/4
or 1/2 wave acting as (anti) phasing lines and messing up the pattern. I wanted
3 el. vertical array, it offers 6 directions and is better suited to serve
heavy ham population areas better than 4 square.
With cables and wires "hidden" inside the towers we have a situation more
looking as a leaky coax rather than Faraday shield. There is a different (common)
current on the coax shield than on the tower. When tower is used as a
vertical on low bands, the situation is a bit better, but depending on cable routing
and connections, the differences can happen, causing some arcing in "weak"
73 Yuri, K3BU
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