I served in the Soviet Army I had contact with a military radio
station that was used such Underground Antennas. The station was
from Sverdlovsk (now Ekaterinburg). My station
was near Moscow.
(I.G.: Distance Moscow- Sverdlovsk is 1800 km.) We used band 3.0- 6.0 –MHz
at the winter and 4.0- 8.0- MHz at the summer. The station with
Underground Antennas was heard by S5- S6. When the station was
used the usual stationary antennas it came to us by S9+.
asked the chief of the radio- center about the Underground antennas.
He told me that he saw how the antennas were installed. It was
thick coaxial cable that was buried in trenches in 2.5- 3.0- meter
Underground Antennas were at the receiving radio- center where
I was served (in the Soviet Army). There were symmetrical antennas.
The antennas were reserved ones that supposed to be used at emergency
situation (at nuclear war)...
took part at installation of the Underground Antenna… It was coaxial
cable (looks like) near 10-cm in diameter. The coaxial cable was
buried on 50-cm into the ground. I used the antenna with a transmitter
The antenna matched well but the efficiency was low. The antenna
was tested up to 6- MHz.