About the antenna that is shown on the Figure 6.
Inside of the “plate” there is a radiation helix made of from
a copper strip.
The antenna is tune up from 1.5- to 30- MHz with
help of vacuum capacitors and additional coils… The antenna is
working on RX/TX. The “plate” with the antenna parts is filled
on by a special plastic.
There is some more info about the underground antenna “Astra.” It
had length near 100- meters and width near 30- 40- meters. Antenna
was placed above a slope. Decline the slope in to the direction
of the directivity of the antenna is near 5- 10 degree. Antenna
was made from pieces of coaxial cables in 50 and 75- Ohm. Joining
of the cables was insulated by melted polyethylene in special
die mold. The ground on it the antenna was sitting should have
special parameters. It was coarse sand. The sand was transported
to the antenna place for 40- km.
Underground antennas were intended for reception in the VLF (Very Low-Frequency
waves). System “V’uyga”
used the antennas for VLF reception. However since 1980 the system
“V’uyga” was used magnetic loop antennas made in Petropavlovsk
Note I.G.: System “V’uyga” in the ex-USSR Army was used
for assured delivery of orders (issued by a man) and signals (issued
by some electronic system) to the army divisions. System “V’uyga”
duplicated signals and orders that were transmitting by the usual
channels of the communication. System “V’uyga”
may use radio frequency bands from VLF to UHF.