Recently, we made an antenna for 40 and 80 meter bands in our radio club, UN9GWA.
Here’s the video (in Russian but radio amateurs will understand what is going on):
The antenna is a closed loop of copper wire, a little bit longer than 80 meters.
The exact length was adjusted so that the internal tuner of our Icom IC-7600 was able to tune it for the 40 and 80 meter bands.
The antenna is stretched between our balcony on the ninth floor and the roofs of two neighboring buildings.
Because the wire is thin, the bandwidth is not large, and the antenna is not tuned for the whole 80 m band.
However, its length is adjustable. We soldered several terminals, half a meter apart, so we can change the length which shifts the resonant frequency within the band. This is what we do on the balcony in the video during our antenna party where we also made a fruit salad and cookies with marshmallow and chocolate by melting them under the sun.
Making antennas is fun. Seeing them work is even more fun!
Best wishes from our radio club!
73 de UN9GWA