If your inverted L is any good at all it will suck as a receiving
antenna. This is one of the key things to accept about medium wave
but many casual 160 m. operators can't wrap their heads around it. A
flame throwing tx antenna will probably have a completely unacceptable
noise level on receive. Tx/rx reciprocity works on HF but not as well
on medum wave. Separate rx antenna(s) are mandatory. A
significant irritant on 160 are the operators with poor antennas that
hear great, therefore they expect to be heard equally well, and can't
be made to believe they are piss weak when they transmit.
I'll pass along one idea I got from a friend of mine regarding your
tree holding inverted L. Since the tree is probably a substantial
support, I'd lower the L (this is assuming you have a pulley on a rope
over the branch, through the pulley another rope attached to an
insulator through which the top of the inverted L transfers from
vertical to horizontal, all to facilitate raising and lowering) and
bolt three more copper wires to the current wire, near the point at
the insulator, with one wire continuing on through the insulator. The
3 new wires should be long enough to drape down to the ground. Now
pull it back up and spread your four wires so that near ground, each
one is in the corner of a square with 6 to 12 feet on a side, each
wire attached to an insulator which in turn is attached to a rope that
proceeds on to an anchor stake of some sort. Next, run a ring of wire
around the square you have made so all four vertical wires are bonded
to each other, the square wire being around two feet off the ground.
Bring in your feedline and connect it, or your matching network if you
have one out there, to the ground system and the square ring wire.
I'd use awg 14 7 strand hard drawn bare copper wire for all of this.
What you will have done is a wire simulation of a free standing tower
insulated from ground with a 6 to 12 foot face around 100 feet tall.
You should have a very flat impedance curve with this which will
greatly simplify covering the band with minimal matching network
adjustment, and at much less cost than what a 100 foot 12 foot wide
skirt fed tower would cost. If I had a tree like what you must have,
this would take me all of two seconds to decide to do.
Rob
K5UJ
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