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Re: Topband: Dual feed for Pennants

To: "Topband Reflector" <>
Subject: Re: Topband: Dual feed for Pennants
From: "Luis Mansutti IV3PRK" <>
Date: Tue, 23 Jun 2009 21:32:34 +0200
List-post: <">>
Greg ZL3IX wrote:
> I have the opportunity to extend my remote Rx site with a couple of
> phased Pennants for the SE/NW direction.  I intend to cover both
> directions with a single pair of antennas, and use relays to switch
> between load and feed at each one.  I will be using W8JI's feed
> transformer design with two transformers per antenna.  For convenience,
> I am thinking of putting the relay in a box at one of the feed/load
> points and running a coax right through the middle of the antenna to the
> opposite feed/load point.
To cover two directions with broadside phasing I use four Pennants, one in 
front of the other, in two groups, with point fed (and the loading resistors 
are in the middle of the opposite vertical wires).
Each Pennant has its own binocular transformer in two elevated switching 
boxes at a 90 m. distance.
>From there the feedlines of the same length reach a central buried box to 
joint in a T connection followed by a binocular 2:1 transformer.

I put many details and pictures on a PDF file downloadable here

> but I was wondering if anyone is using a similar
>arrangement, and, if so, what the results are.

The results are very good but only in a limited azimuth direction, as the 
lobe is typically sharp. A few degrees out of the preferred direction it's 
usually better to switch on a single Pennant, with a lower RDF but a broader 
cardioid pattern.
This switching option is sometimes also useful to move the rejection null 
from the sides to the back, and viceversa... but I guess QRM is not an issue 
in New Zealand, Greg !



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