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Topband: Beverage feed line...too long?

To: topband@contesting.com
Subject: Topband: Beverage feed line...too long?
From: "Alessio Sacchi" <iz4efn@gmail.com>
Date: Mon, 17 Sep 2007 21:55:07 +0200
List-post: <mailto:topband@contesting.com>
Hi top banders,

just yesterday we installed our first beverage at IO4T site, after a couple
of years running a (we believe ) succesful K9AY.

The beverage is 200m long (600ft) and 6 feet (2m) above the ground.

The feeding line is a 300m (900ft) RG-58 MIL line.

The K9AY is feeded with 200m (600ft) of the same cable.

The first comaprison between our two RX antennas shows a  pretty noiser
beverage than expected. Actually, the two antennas show the same noise
level, and almost same signals in that direction.

After reading ON4UN, we have some dubts about our setup:

Is it possible that such different antennas have same noise? Do you think we
should expect an S3-S4 noise also on the beverage?

We also performed the ON4UN's open feedline test: leaving the feedline
disconnected brings in the shack some udible signals on 80 and 160m.

We are now pretty sure that the 300m RG-58 are acting as an antenna (please
note that the cable goes straigth to the beverage, no middle-ground or beads
termination). Now, the main issue is about our comparison setup. Are both
the K9AY and BEV having common mode interference through the feedline?

We are wondering if at least the K9AY is working well, since we never heard
another one.

Last but not least question: what would you hear in a well designed shack,
comparing a K9AY and a beverage beaming the same direction?

Thank you for any kind help

Alessio IZ4EFN.
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