----- Original Message -----
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
