This is one of the shortest electrical halfwave antennas I've ever tried. It was designed around the Cabelas 14-foot crappie pole
. This fishing pole collapses down to 15.5 inches, so it's very compact and portable. In fact it is what I'm using on my new sea kayak
for marine mobile operating. I had my doubts about the fishing pole
because it is made of graphite. In fact, initial tests showed wildly
varying swr as the wire slapped against then away from the pole in a
breeze. I solved that by wraping the wire lightly around the pole a few
times and taping it down near the coils. Now I get rock solid swr
readings, and the conductive graphite doesn't seem to affect the sent
or received signal (although it must be to some degree). I tune all of
my EFHWA antennas with a homebrew L-C matching unit
. Look at the bottom of that page.
I had made some CW contacts earlier in the Fall with the new antenna,
but October 20, 2006 was the first time I tried it with a microphone. I
was out with my sea kayak in a lake near Golden, Colorado and
running 5 watts on 20 meters. It was satisfying to hear signal reports
coming in confirming the very shortened antenna was getting out
coast-to-coast. Here is a rundown of the first eight sideband contacts
and the signal reports:
Call state report
N6KKS CA 59
WD9EML IL 53
W7DK/90 WA 59
W8ELG MI 54
WB6LNH NC 51
W9H IL 57
NA4BH AL 53
WB7EXB NV 57
While I was working special event station W9H, a TI2 station broke
in to say, "Tell the kayak mobile he's making it into Costa Rica."
Unfortunately, it was a busy frequency and I never got a chance to have
him QSY with me.
The antenna is made from stranded, 26 ga. Teflon-coated wire. There are
three sections of wire connected by two loading coils. The outer
sections are 36.5 inches in length, and the center section is 88.5
inches long. Adding both 3" coil forms gives 14 feet, 4.5 inches total
The coils are stranded, 22 ga. wire wrapped around 3 inches of thin-walled 3/4-inch
(schedule 20) PVC tubing. Then it's covered with black electrical tape.
Alligator clips allow switching of taps for different bands.
I recorded the number of turns I used to tap for each band for future reference:
10 meters = 8 turns
12 meters = 12 turns
15 meters = 17 turns
17 meters = 24 turns
20 meters = 41 turns (full coil)
This is certainly a compromise antenna at only 42 % of full size on
20m, but even on it's lowest band it appears to perform well enough. I
can't wait to try it out on 10 meters.