Topband: Inverted ELL for 160M
Jerry Keller
k3bz at arrl.net
Mon Nov 1 21:32:14 EST 2004
I've been wanting to try top band for a long time, and after scouring the books on my shelf and a
few internet sources, here's what I've come up with (tentative) that will fit on my lot:
The vertical section of about 60 feet would be supported by a tree, with the horizontal component
about 70 feet. (I could make the horizontal longer by 10 or 20 feet if need be. I've read that
lengthening the horizontal segment may increase the bandwidth?) I would be able to raise and lower
the far end of the horizontal segment for trimming as needed.
The feed point would be about 8 feet off the ground (at the top of a 4x4) with two elevated 1/4 wave
radials 180 degrees apart, and 90 degrees to the horizontal segment. The feed point support rises at
the top of a mound so the ground slopes away rapidly putting the radials about 12 feet off the
ground for most of their length. The radials and the feedline shield would be connected by #4 solid
copper to a ground rod directly under the feedpoint.
I had thought about feeding it direct with 50-ohm coax, but a friend tells me I'll be much better
off with two electrical 1/4-wave lengths of 75-ohm coax in parallel between the feed point and the
single point ground box at the house (just about the right length, too) and connect there to the
lightning arrestor, with about 25 feet of 50-ohm coax from the arrestor to the rig. He says that
should match pretty well.
How does all this sound? Any suggestions? Any help or ideas or suggestions you might offer will....I
assure you.... be deeply appreciated.This will be my first attempt at top band and I'd like to do
the best wire antenna I can before the snow flies here in eastern PA.
Thanks in advance, Jerry K3BZ
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