A Practical Antenna
for 160 Metres
This radio amateur antenna, as described by Frank G3YCC, should
work fine as a receiving antenna for any short wave listener with
little space.
The antenna
consists of 140 feet of insulated wire, the first half of
which (70 feet) is space wound on an insulated tube. I used glass
fibre tubing which was to hand, but PVC may be used also. My tube
is 1 1/2 inches in diameter and about 5 feet 6 inches long. The
turns are about 0.5 inches apart. The other 70 feet of wire acts
as a loading wire and slope down from the top of the coil to near
ground level. The system is coax fed to the base of the coil,
with the shield or braiding going to earth.
It appears to work very well, apparently giving some horizontal
and vertical polarisation.
One great
advantage is that the system can be tuned without having to
lower the mast - by pruning the loading wire to resonate on the
required part of the band. Bandwidth is also good - mine is about
30 kHz either side of resonance. I found the MFJ Antenna Analyzer
MFJ-259 invaluable for this project, as well as many other experimental
systems.
Ensuring an efficient earth system will add to the effectiveness
of the aerial I still have to improve my earth system, currently
it consists of two 140 ft radials and connections to some buried
guys stays. Alan, G4ERZ, has a far more elaborate and efficient
ground and his results prove what we all know - the ground (or
earth system) is all important. He is a tremendous signal on 160
DX wise. He still gets the same band width as I do, though.
I have
worked a few DX stations with it since erecting it only a
short while ago, and I think it has a lot to offer, especially
for those of us blessed with relatively small gardens.
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