I find it difficult to believe that there is any different loading seen at
the bottom of two L's in parallel but with opposing horizontal parts from
that seen by a single wire vertical to the Tee or that there is any
different current distribution or radiated pattern.
If there are those that do not then I ask::
what is the voltage difference between the two vertical wires at their
respective junctions with their own horizontals ?
Bryan G3GVB
----- Original Message -----
From: "hamilton mal" <[email protected]>
To: <[email protected]>
Sent: 28 December 2003 18:04
Subject: LF: Re: "T" versus "L"aerial
----- Original Message -----
From: Dick Rollema
To: LF-Group
Sent: Saturday, December 27, 2003 2:09 PM
Subject: LF: "T" versus "L"aerial
To All from PA0SE
Further to my e-mail of 26 December I measured the field strength as
radiated by the aerial in
Inverted L-configuration. From this I found EMRP = 57 milliwatt.
This confirms the benificial effect of top loading. The T-aerial radiated
140 milliwatt.
So going from a single 20m top load wire for the "L" to 2 x 20m for the
"T" resulted in an improvement by a factor 2.46 (3.9dB) in radiated power.
The vertical part of the "T" consisted of an open wire feedline of 11m
with the two wires connected in parallel in the attic shack. For the "L" one
of the feedline wires was removed. I assume this did not appreciably affect
the EMRP.
HI Dick
From your explanation using open wire feeder you are using an inv L with
one feeder wire connected and with the 2 feeders strapped at the shack end
then you have two inverted L antennas in parallel. A true T antenna has
both feeder wires connected at the top as well as the bottom, in fact do not
use open wire feeder, connect one wire to the centre of your T horizontal at
the top and the bottom of your single wire to the loading coil and matching
unit.
73 de Mal/G3KEV
.
73, Dick, PA0SE
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