Hello Martin,
I assume you're talking about RX antennas?
If you want to use a loop, maybe you want to build an own loop for 137
kHz that is placed as far as possible from the house. The size (enclosed
area) may be smaller. You may use a coax cable going to the shack (maybe
RG174) that is grounded in the garden, with an own LF earth rod. Then
you can use a transformer to couple the signal to your RX.
There are several ways to do it and the best SNR that can be achieved
depends on the local noise situation.
I am rather a fan of small E probe antennas since they are easy to build
and can easily be lifted to 10 m above GND, e.g. with a small plastic
rod. But my experience with loops is small, maybe i become a fan of them
too soon :-)
73, Stefan/DK7FC
Am 09.06.2011 12:07, schrieb Martin Evans.:
Gentlemen - some advice, please.
My radio room is in a bedroom at the back of my house.
Currently, I use a wire running from the bedroom up to a pole on the
chimney about 35ft (10m) above ground, then to a pole at the bottom of
the garden about 100ft (35m) away, then down to the bottom of the
pole, where it is tied off.
I tried running the wire back to the house (end not connected to
anything) at about 8ft above ground (2.5m) but this runs alongside a
long building with my office, with electicity cables, computers, etc,
so it picked up a lot of noise.
The signals seem "cleaner" when this return run is cut off.
How can I improve this setup?
I am thinking of pulling the far end of the wire over to the other
side of the garden and running it back to the house there, probably
about 10ft (3m) above ground, then back inside to make a loop.
I would then have a loop aerial in a 45 degree plane, roughly.
Does this sound as if it could be an improvement over my current
setup? Would lifting the bottom of the loop up to be more horizintal
be better or worse?
Any other suggestions?
My garden runs roughly East-West. Does my current "Inverted U" aerial
have any directivity at this frequency (137kHz)? What would be the
directivity of my proposed 45 degree loop?
Thanks for any help & suggestions,
Martin GW3UCJ deep in the Swansea Valley!
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