The thin wire 160 metre G0CWT Loop that I use
is shown in the Sketch. The dimensions
starting at the bottom left of the wire are 30 foot up to the chimney,
then 58 foot across to the mast, 12 foot down to the nylon tie and 28
foot back down to the shack roof. a total of 128 foot of wire. The Loop
is pulled into shape by the nylon cord from both the chimney and the
mast.
The box shown on the roof of the shack
contains a variable capacitor and the ferrite transformer which uses
three turns for the primary winding to connect to the 50 ohm coax
feeder, The secondary is two turns and connects between the loop and the
capacitor. A description of the ferrite core can be found at
www.edginton.info If more
information is required E-Mail me at --
ben@edginton.info
--
The shape of the Loop is not important but
will change the direction of the main radiation which is normally away
from the capacitor and through the loop center point.
When 128 foot of wire is used in this loop
it can be resonated on the 160 meter band and is capable of DX on this
band.
On forty metres this 128 foot loop is a full
wave loop and by switching out the capacitor and switching in extra
turns on the secondary making a total of six turns it becomes an
excellent antenna on forty metres and will also work on all the other
bands through to ten metres (except 80mtrs )although an ATU may be
needed on some of the bands to get a one to one SWR
The only exception is 80 metres this is
because it is a one half wave length loop and the feed point impedance
becomes very high. This makes it necessary to use an additional matching
transformer to bring it down to 50 ohms and this is not very easy to
achieve. for this reason I still use the 64 foot loop for 80mtrs .
I have used the 128 foot thin wire loop on
all the other bands and find that I can get through a pile up with less
than 100 watts and can have a TV switched on in the same room while
transmitting without any sign of interference.
I still favour the 64 foot G0CWT Loop for 80
metres it uses a thick wire element made from multi core cable and can
be tuned to resonance at 80 metres giving it a better radiation pattern
towards the west when the capacitor is on the east details can also be
found at
www.edginton.info
-it is excellent for DX as well as inter
G work.
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