I finally got my 80m loop up yesterday. I used the ARRL antenna handbook's
"loop skywire" design. Wire is 272' for resonance at 3.7 mhz and fed with 450
ohm ladderline about 1' off a corner. Height is low (30') but that was the
I could go with the trees available. Its a start anyway. Maby I can improve
I'm using a Yaesu ft920, 3' coaxial jumper to manual tuner, 6 or 12' coaxial
a 4-1 current type remote balun (Radio Works), then ladderline to loop. I am
a balanced tuner to replace the manual tuner and the remote balun and allow me
amp occasionally when I can afford the rest of the components I need.
I'm very pleased with most aspects of it. Its much quiter than my old dipole
seems to have considerable gain on 40m and up. 75m is even to a some better
the old dipole except for the quiet noise level. I really like the quiet. It
will tune 160m
and the old dipole wouldn't. My first three contacts were on 160m and I got
signal reports ranging from s9 to 10 over. That me smile.
Here are the questions.
I cut the wire for 3.7 thinking that the loop would be closer to resonance on
40m and up
rather than cutting it for my real area of interest (3.85 to 3.95). I did it
this way on advice
of another loop user but he feeds his with a very short length of coax and
lives for cw.
Is this correct or should I trim for my area of interest on the lowest band
(3.9 mhz) and let
the tuner take care of the higher bands???
My ft920's auto internal tuner handles the 40m and up with a push of the button
but balks some
on 75m or 160m. The internal tuner will find a match but not using the on
touch memory tune (says
high swr). I understand that on 160m but 75m should be in range of the tuner
unless the wire length
or feedline length is a problem.
My feedline (ladderline) is somewhere between 118 and 125' long and thats close
to a half wave length on 75m.
I can remove a little or add more by routing the feedline. Any suggestions
about how much I need
to trim/add to get the tuner working properly. It does tune fine on the manual
mfj tuner but I think it has more
Thanks in advance
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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