was made by me in one of the hot summer days at the 1998. I was
going for weekend to my bungalow and I decided to take my home-
brew 80- meters transceiver with myself. I had no antenna for
the transceiver. So, I needed to do the antenna, but... I had
no time as I have no quality stuff for doing this one. I opened
my junk box with old stuff... and... Thirty minutes while I have
had a new antenna that served me then several years!
I have done a half wave antenna
with "bottle"matching device. Figure
1 shows the antenna. As you can see a wire
in long of 40 meters (a half wave antenna) is matched with 50-Ohm
output of my transceiver with help of a parallel circuit ("bottle"matching
device)- it is L1C1 in Figure
1. Inductor L2 has not electrical connection with
antenna circuit. RF energy is transferred only by magnetic field
that reduces the level of static interferences at receiving mode.
The counterpoise has length of 20 meters of a naked
copper wire in diameter of 1.5 millimeters (#14 AWG).
I used a wire from an old burned
down electrical transformer 220-V/12-V.
The counterpoise serves both
as electrical and radio grounding for the antenna. At operation
time of the antenna the counterpoise is placed on the ground in
any position (straight or bending). To short static electrical
charge from antenna wire to ground is main task of the counterpoise.
Not wise to use a long antenna in the field without an electrical
ground, because at the first it is unsafe, and in the second,
the antenna is very noisy on reception without the electrical
2 shows the construction of the matching device. I used
a half - liter plastic bottle in diameter 60 millimeters from
a mineral water. C1 is attached at a side of the bottle with help
of a strong copper wire in diameter of 1 millimeter (#18 AWG).
L1 has 15 turns of a copper wire in diameter of 1.5 millimeters
(# 14 AWG), length of winding is 70 millimeters.