Hi Rodger,
You will have better success if you add a top loading wire to your mast,
which makes it into an inverted-L. Suggest you start with an 80 foot wire
in a straight line if possible but otherwise route it any shape necessary .
You can increase or decrease the length of the top loading wire to improve
the match.
As an alternative to shunt feeding your mast, you could simply install an
130 foot inverted-L parallel to your mast and direct feed it from the
bottom.
You could add a loading coil to the wire if 80 feet is too long.
73
Frank
W3LPL
----- Original Message -----
From: "rodger bryce" <gm3job@hotmail.com>
To: topband@contesting.com
Sent: Friday, August 7, 2015 2:54:40 PM
Subject: Topband: Top Band Antenna
Gentlemen, I have the following which I would like to turn into a topband
antenna if possible. My mast is approximately 40 feet high and there is rotor
cage with a 10 foot stub mast, on the stubmast I have an 8 el.log periodic and
above that a rotary dipole for 30/40m.
I attached a drop wire at approx. 38 feet high, I grounded this wire and tried
to grid dip the wire plus mast, all as per ON4UN's book "USING THE BEAM TOWER
AS A LOW BAND VERTICAL" the results were zilch, nadda nothing at all, no dip
anywhere on any band. I used the MFJ 259B with the GDO accessory.
1. Am I doing this all wrong......highly possible.!!
2. Is the mast not high enough to be used for top band.?
I am totally out of my depth here.........so any guidance would be much
appreciated.
Many thanks, Rodger/GM3JOB
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