used the Underground Antenna at the radio- center where I served.
However, I do not know nothing about
design of the antenna. The antenna works worse compare to usual
(placed) on ground antenna. It is a reserved antenna that would
be used when the usual stationary antennas were destroyed. However,
for survival purposes the radio center and its electro station
also should be placed underground….
constructed one of the Underground Antennas at 1984- 1986 years.
It was not so far from Kaluga (Russia). The antennas were placed
on a field with several km in (L/W) dimensions. There were installed
(in some depth) coaxial cables and copper arrays. Then all were
buried and the place was finished to flat surface by bulldozers
DT-500 and DT-1000.
I do not know for what the frequency band the antenna were designed.
saw such antenna near Tarusa, Kaluga- region when I served in the Soviet
Army. It was Summer – 1987. Soldiers (from unit where I served)
for two days did masking of the antenna. It was practically flat
filling (near 2 meters height) with size of a football pitch. There were
crushed rocks in bitumen and some strange (looks like selicagel)
“balls” in the filling Upper the filling there was a grid from
thick (near 40- mm in diameter) coaxial cable. We took topsoil
from a nearest water meadow and put those one a top of the filling.
When I served in the Soviet Army (it
were 1976- 1978 years) I constructed the Underground Antenna near
region. It was a grid from a coaxial cable RK-75-24x17. It was
very heavy coaxial cable in 60-mm diameter. The antenna was tested
from several tens kHz up to 20-MHz.
from I.G.: Russian coaxial cable RK- 75- 24x17
is special steel-clad, water and moldy protected cable that can
be installed under the ground.)
the 80s I was served at a communication unit near Leningrad (today Sankt- Peterburg). There
was an Underground Antenna. I remembered that we used to the antenna
with radio R-140 for communication with Monchegorsk. (I.G.:
Distance between Leningrad-
Monchegorsk is 1200 km.)
I.G.: Underground Antennas with fully automatically
underground radio- centers were (or are) widely used in the Soviet/Russian
military system Dead Hand (also known as Perimeter, Hand from Coffin).
More about the system: http://en.wikipedia.org/wiki/Dead_Hand_(nuclear_war)