80 Mx Multiband
Horizontal Loop Antenna
antenna covers the 80, 40, 30, 20,
17, 15, 12, 10 and 6 Mx
Amateur bands. Multiband operation is
achieved by use of 300 ohm balanced
line fed to an antenna tuner. This
loop antenna needs to be run in
the horizontal plane. ie. parallel to
the ground. The formula used to
determine fundamental frequency wire length
is :- Length (feet) = 1005 / Frequency (Mhz).
I operate mainly CW, so I cut
the wire length, for the 80 Mx
band, to 88 metres (287 feet). If
you operate SSB, the length of the
wire will need to be shorter, in
accordance with the above formula. I
used high tensile fencing wire in
the shape of a square supported by
four trees. The winds here can be
ferocious so strong wire is needed
even though radiation efficiency will be
compromised by using fencing wire. Since
our HF bands are harmonically related,
this length of wire covers all HF
bands from 80 mx up to 10 mx,
including the WARC bands. If the
wire is cut for the 40 metre
band, about 44 metres of wire or
slightly less, the antenna can also
be used on all the higher HF
bands. Of course, a perfect square
of wire is far from achievable here.
A circle is theoretically ideal but
even a triangle of wire will work.
The feedpoint of the antenna can be
placed any where but I positioned it
about two feet from the corner. The
diagram below gives you some idea of
This image shows one
of the trees to which the wire
The trees at this
location are not very high so the
average height of the antenna is
only about 20 feet or so.
The feedpoint can be
seen on the left. I used 15
metres of 300 ohm ladder line
which can be purchased
in various lengths from
A perspex block and
splicing tape reduce the strain on
the feedline at the feed point.
Rubber splicing tape
can also be purchased from
One 'corner' of the
The operating position
located in an old caravan which is
solar powered. The tuner can be seen
left. The radio is
the Yaesu FT-450.
The Tuner - MFJ-969.
Even at a low
height, this antenna performs very well.
Surprisingly so. One of its attributes
is that it is quiet on receive.
Another is that it has many
radiation lobes and therefore works well
in several directions. It costs little
to build. It's straight forward to
construct and fairly easy to erect,
although in my case I had a
sore shoulder after throwing the lines
up into the trees. This multiband
horizontal loop may be the antenna
you are looking for.