Antenna of the Month - February 2003.
Details supplied each month by George, G3NIR
Antenna of the Month
III
This month is a
follow on to the Extended double Zepp of last month
The antenna is for
21Mhz.
Parts list:
60 feet of either
stranded pvc covered or copper wire.
2 metres 450ohm
ribbon feeder
2 egg insulators
1 dipole centre as
before ribbon feeder type.
50 ohm coaxial cable
1:1 balun.
To construct, fold
the 60 feet of wire in half and cut into 2 X 30 feet pieces.
Fit an egg insulator
to each of the 2 pieces of antenna wire.
measure 28 feet from
the egg insulator and join to the dipole centre the 2 wire pieces,
leaving a tail on
each to enable them to be joined to the 450ohm feeder Join the 450 pohm
feeder to the two
tails and make good waterproof joints as before if possible seal these joins
in a film canister
and fill with epoxy resin. Measure 1.95m down the feeder and cut leaving
tails for joining to
the Balun.
The balun can be
either a commercial 1;1 balun of construct one from 5 turns of coaxial
cable with a diameter
of about 10 Cm.(5 inches). Make sure that the join at the coaxial is
good and waterproofed.
Hoist as high as
possible into the air and you have a good antenna with 3dB of gain on 21Mhz.
A good DX band this
antenna can be used as with the 300 ohm feeder type of last month on
all band above 21 Mhz
and down to 40 metres. Connect to
your ATU and good DX.
With thanks to Robert Snary G4OBE
and Practical Wireless.