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Topband: Summary: Beverage feedline suggestions

To: topband@contesting.com
Subject: Topband: Summary: Beverage feedline suggestions
From: David J Rodman MD <rodman@buffalo.edu>
Date: Sat, 06 Mar 2004 07:27:30 -0500
List-post: <mailto:topband@contesting.com>
Thanks to all the people who responded to my inquiry about how to and what to feed my new beverage antenna with. I haven't acted yet, but the materials are on order.

First, I decided to scrap the Mini RG-59 cable that I hastely put up at 11PM in the woods the other night. I believe that coax is better suited for either bazooka dipoles or beverage listening wire.

Secondly, I plan to use a RG-6 QUAD. I got a price of 10 cents a foot. This seemed pretty reasonable. I ordered F-SO-239 adapters because one can not solder the aluminum shielded RG-6 to typical PL-259 connectors. I already have the necessary crimp tool. I use rubber tape for all coax connections outside, paint all screw terminals with liquid electrical tape and cover the terminations with small plastic bags after wrapping with wire ties.

Third, I plan to check the VSWR of the antenna today with my Autek instrument. Respondents have convinced me if the system is grossly mismatched, there will be additional losses in the feedline which are significant and might be substantial. Since the feedline directly to the receiver is all 75 ohm, I plan to set the desired Z or the transformer tap for as close to 75 as possible. It would be nice if I could listen to the receiver while doing this however. Unless anyone else has a better solution for determining the match, I will do this. Right now, the termination resistor is 450 ohm and the tap on the transformer match is selectable 200, 400, 600 or 800 ohm ( I pre-set it to 600).

Forth, I revisited the issue of how much loss I am getting with the present setup. I would say the difference in station strength is substantial. When compared to European stations and a mainly East pointing antenna which has a 600' shorter feedline, the new antenna is always 2 S units quieter to noise and signals. When signals go over S9 there is a clear indication of a 10dB difference. Therefore, I do not believe the signal loss is insignificant 2-4dB.

Thanks, Dave.

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