[Elecraft] Good Low Horizontal Loops - questions

[Ron D'Eau Claire]

Lloyd wrote:

I could probably string a roughly circular 1K' loop on
my lot, through the trees, with an average height of
about 50'.
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That 50' height is a winner. No wonder you are working tons of DX with a
"random wire"! 
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 Here's what I need to know, though:
... is the loop broken, with one
side of the feedline going to each side? If so, is the
distance across that gap critical? 
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Ans: Yes and no. 
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What types of
feedlines would work - which would be best? Can I use
twinlead? Would I need a balun, an rf choke, or
whatever?
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A multiband loop is normally fed with "open wire" line such as ladder
line or twinlead. The lines with larger conductors and lots of air
insulation are best. Twin lead suffers from rather large change in
electrical characteristics when it is wet or has ice/snow on it. That
can radically change the tuning required, but with using the KAT1 that
shouldn't matter. A balun MIGHT be called for if you seem to have a lot
of "r-f" on the rig - if touching it changes the tuning, etc. That only
happens if you have a high impedance point at the rig on some band. It's
hard to predict, but the bigger the loop (or the longer the random wire)
the smaller the impedance extremes you will see, and so the less likely
you will have trouble that way. 
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My rig is a K1 with KAT1, 40-30-20-15. Would one end
of the feedline go to the center conductor, and one to
the ring?
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Ans: Yes. unless you want to use a balun to try to make the feeder
"balanced". 
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 Would I need counterpoises? 
-----------------
No. 
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Will the
feedline radiate? Is it ok if it does?
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Yes, the feeder will radiate unless the currents in the feedline are
very well balanced. No, it won't bother the performance as long as your
feed line runs 'in the clear' not where the r-f will be absorbed greatly
by surrounding objects, or where noise-generating devices and put r-f
onto the feeder to interfere with reception. If your feeder tends to run
all over the place, I'd suggest using a balun. But under some conditions
where you are looking into the wide range of impedances you will see
with a multiband antenna like that, baluns can consume a significant
amount of power. There are several ops on the reflector here who have
done a lot of work with baluns who can offer some additional
suggestions. My choice is to avoid them unless I am really concerned
about avoiding feedline radiation. 
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I'm now using a
longwire of about 200' that goes every which way, and
works very well - good reports all over Europe, down
to Central America, and domestically. Should I be
satisfied with that, and cease this endless restless
quest for gain? 
-----------------------
After 50 years of pounding brass, I've come to the conclusion that a
"real Ham" is NEVER satisfied with his/her antenna, and spends much of
his/her life trying to make one work as well as that one he/she
remembers having years ago that pulled in so much DX, Hi!

Ron AC7AC
K2 #1289