For several years I use to a simple and rather effective
home- made antenna for a work from my balcony, a hotel window,
from the ground in a radio- expedition and from my car. I with
my friends have made dozen such antennas and all the antennas
work very well. One antenna, in depend of its dimension, works
at three old amateur ranges- 10, 15,20 or 15, 20,40, or 20,40,
Figure 1 shows the
antenna. Antenna wire is a tube or copper or bimetal rod of 5-12-mm
diameter (#0000- 5 AWG). D-E wire is thinner then a-c-b wire in
2-5 times. Antenna is tuned by air (a vacuum capacitor is better!)
variable capacitor with air-gap in 2-mm. The capacity is
L = 1.57AB
CD = 5-8 centimeters
AC near 0.2L
Most high frequency for the antenna is: 4 (AB+L).
To run a QRP power at most high frequency for the antenna.
Move a crosspiece CD to find the minimum SWR. Check position of
the crosspiece. To run a QRP power for next working band of the
antenna. Move a crosspiece CD to find the minimum SWR. Check position
of the crosspiece. And so on.
To stand the crosspiece by manually or by RF-relays
for choosing band. The antenna has very high directivity,
so, choose needed position for the antenna. Switch your transceiver
I tried the antenna at different conditions and everywhere
the antenna works well, from my house, from my car (the antenna
is placed at boot of my car), from a field. I use to the antenna
with IC-706 MK2G.
I wish all good luck! 73!