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Re: Topband: Topband Tower Antenna With Two meter Vertical

To: topband@contesting.com
Subject: Re: Topband: Topband Tower Antenna With Two meter Vertical
From: W0MU Mike Fatchett <w0mu@w0mu.com>
Date: Sun, 15 Apr 2012 12:01:15 -0600
List-post: <topband@contesting.com">mailto:topband@contesting.com>
I heard that there is a reason to run the coax on the outside of the 
table as running it inside can create some issues.  I just don't recall 
what it might have been or if the warning was based on fact or just 
anecdotal comments.

Mike W0MU

W0MU-1 CC Cluster w0mu.net


On 4/15/2012 10:28 AM, Jim Brown wrote:
> On 4/15/2012 8:49 AM, Wayne Rogers wrote:
>> Also - on the antenna installation.  Typically the two meter vertical's 
>> outer conductor will be grounded to the tower at the base of the two meter 
>> antenna.  I could also keep the two meter antenna insulted from the tower 
>> for its entire length up to the lightning protector just before it enters 
>> the house.  What's the recommended practice?  Ideas?
> First, always run rotor cables and coax for antennas mounted to the
> tower INSIDE the tower. This allows skin effect to minimize 160M current
> on those cables.  Second, proper bonding of the coax shield to the tower
> top and bottom is good practice for lightning.  Third, coming away from
> the base of the tower, wind as many turns as you can of each cable
> through at least one #31 toroid.  This prevents these cables from
> becoming part of the radial system.
>
> Ferrite beads clamped onto a cable are next to useless on the HF bands
> because they are inductive, not resistive, so all they do is TUNE the
> cable to which they are attached.
>
> If the tower is very close to the house, it should be bonded to the
> combination of all grounds in the house, which, MUST be bonded
> together.  That includes power entry, telephone entrance, cable TV,
> satellite dish, ham shack, etc. If the tower is distant from the house,
> only the cables coming from the tower should be bonded, not the tower
> itself.
>
> 73, Jim Brown K9YC
> _______________________________________________
> UR RST IS ... ... ..9 QSB QSB - hw? BK
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UR RST IS ... ... ..9 QSB QSB - hw? BK

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