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[TenTec] CW, Antennas

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Subject: [TenTec] CW, Antennas
From: geraldj@ames.net (Dr. Gerald N. Johnson, P.E.)
Date: Fri, 25 Dec 1998 17:33:37 -0600
Al, many otherwise good keys are made for being bolted down. Even the
J-38 tips until the binding posts are removed and the base reversed.
I've had Johnson Speed key for about 25 years. I mounted it on a piece
of 1/8" steel from a rack panel with the near end of the steel sticking
out further than the knob. Its only good for 29.8 wpm. I suppose bolting
it to the right desk might improve it, but that's good enough for me. I
like it better than any surplus keys I've had. And the steel slab (about
3 x 6 inches) is far more portable than a key bolted to the table.

As for a place to make contacts, anyplace and anyone that will copy you
and that you can copy is the place. 40m is nearly always useful.

You can acquire eznec easily to test out the computer analysis. You left
out significant details on the path to your dad. To suggest antennas we
need to know how long, and what time of day. Too much vertical
directivity can make him impossible to work. I've looked at lots of wire
beams and find them full of spurious lobes, the longer the wires, the
more the spurious lobes.

Do you want to work the same directions on 20m as on 40, or can you
afford to not work broadside on 20? In that case, I'd vote for a simple
double extended zepp. About 45 meters of wire center fed with tuned
feeders. It will give a little gain broadside on 40, give less gain on
80, and more on 20, but has a null broadside on 20. I used to use an 80m
double extended zepp (95 meters of #10 copperweld) on 160 through 2m. In
its favored directions it worked as good on 2m as a single yagi. It
worked well on 6m too. Takes a tuner on every band. For working your dad
you have to pick a height to get the right bounce. If he's within 3 or
400 miles you want it to be fairly low to put your signal nearly
straight up. Under a quarter wave. Probably work best at something like
20 feet. If the path is longer you need to get higher. 3 db gain for the
double extended zepp and the pattern is cleaner than any V-beam.

Some longer V and Rhombic antennas I've checked, had such strong lobes
that the energy in the side lobes cut their gain by as much as ten db
from that computed on the basis of main lobe beam width.

For tuning, you need a classic series/parallel tuner with a link to
couple to the tuned coil. You don't want to tune through a balun because
the impedances will be damaging to the balun or at least enough to make
it unreasonably lossy. You have to make that tuner, but it will tune far
more situations than the commercial tuners with less loss.

73, Jerry, K0CQ

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