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Date: Mon, 16 Aug 2010 20:31:30 +0100
Message-ID: <AANLkTimwCJFYTmTSf9prm2NmWFybZgyPsFu4GsCM2NdJ@mail.gmail.com>
From: Andy Talbot <andy.g4jnt@googlemail.com>
To: rsgb_lf_group@blacksheep.org, uk500khz@googlegroups.com
DomainKey-Status: good (testing) 
Subject: LF: G4JNT 500kHz beacon Off Airr for a while
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My 503.7kHz beacon is off air for a few days while I resite the mast holding
one end of the Tee antenna.    The original mast was a Al scaffold
pole screwed to a brick buttress strengthening the wall at the end of my
garden.   Recently, and probably due to the prolonged spell of dry weather,
I noticed that the buttress had been pulled away from the brick wall itself
from the continuous tension pulling it outwards for the last 12 years.
Bricks keying the two parts had actually pulled apart!   The wall stayed
solid, the buttress has moved to give a 2 - 3cm gap at the top.

So today,  mounted a 3m scaffold pole in the ground, and the existing 6m Al
scaff pole will be fixed to the top of this, once the concrete has set.
This will be 2m higher at the far end, and the top hat will be 0.4m
shorter   I'm going to remake the Tee antenna, with wider spacing top
hat, and separating the two top arms and feeding with twin open wire feeder
in the middle.   That way it  can function as a fat dipole on HF, or be
strapped together for LF - MF.

The extra height should lead to another 1dB of ERP, but who knows what a new
size top hat will do.   Or the new location of the mast marginally further
from trees.

Andy
www.g4jnt.com

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<div>My 503.7kHz beacon is off air for a few days while I resite the mast=
 holding one end of the Tee antenna.=A0=A0=A0 The original mast was a Al=
 scaffold pole=A0screwed to a brick buttress strengthening the wall at the=
 end of my garden.=A0=A0 Recently, and probably=A0due to=A0the prolonged=
 spell of dry weather, I noticed that the buttress had been pulled away fr=
om the brick wall itself from the continuous tension pulling it outwards=
 for the last 12 years.=A0=A0 Bricks keying the two parts had actually pul=
led apart!=A0=A0 The wall stayed solid, the buttress has moved to give a=
 2 - 3cm gap at the top.</div>

<div>=A0</div>
<div>So today, =A0mounted a 3m scaffold pole in the ground, and the existi=
ng 6m Al scaff pole will be fixed to the top of this, once the concrete ha=
s set.=A0 This will be 2m higher at the far end, and the top hat will be=
 0.4m shorter=A0=A0 I&#39;m going to remake the Tee antenna, with wider sp=
acing top hat,=A0and separating the two top arms and feeding with=A0twin=
 open wire feeder in the middle.=A0=A0 That way it=A0 can function as a fa=
t dipole on HF, or be strapped together for LF - MF.</div>

<div>=A0</div>
<div>The extra height should lead to=A0another 1dB of ERP, but who knows=
 what a new size top hat will do.=A0=A0 Or the new location of the mast ma=
rginally further from trees.</div>
<div><br clear=3D"all">Andy<br><a href=3D"http://www.g4jnt.com">www.g4jnt.=
com</a><br></div>

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