Below are some photos submitted from Rob Vijfschaft
pa3eqb@amsat.org of a Russian
military communications
vehicle which uses an NVIS antenna system:
Photo #1:
And a view of some of the gear inside:
Photo #2:
Photo #3, Another example of an NVIS system:
Hi Patricia,
Read your info on WW2 German NVIS antenna's. Nice.
Did you know that the Russian Army also used NVIS on their
radio-trucks?
One of our members of the SRS (surplus radio society in the
Netherlands
(Holland) - 500 members) has a Russian truck ( model 1990 ),
(see picture #1) which uses an NVIS "dach-antenne".
That's what this antenna is called in German, as "dach"
translates as roof. When I had the chance I studied the Russian
manuals in the
radiocabin and will try to describe this roof-antenna as correctly as
possible from memory .
The 2 loops on top of the Russian truck are attached to 4 isolators.
In the radio-cabin inside the truck is a tuning-unit which is
remotely
coupled, via a multi wire cable, to a tuning-unit in the back of the
truck.
For a look inside the radiocabin, see picture #2. The trx to the left
of the
headphones is the HF-set. On top of the HF-set, exactly in the middle
you
can see the TU-box for the roof-antenna. The TU in the radio-cabin
has
several ranges from 1 to 30 MHz.
The TU in the back is basically a relay-switch with coils to ground
(low
frequency ranges) and caps or direct short to ground (higher
ranges).
If you change the range-switch of the TU in the radiocabin, it
signals ,via
the multi wire cable, to the relay in the back TU to change position.
The TU in the front (radiocabin) is a voltage divider with a
adjustable
vacuum-capacitor and C's which are selected depending on the
frequency band.
The loops on top of the roof can be folded down for driving. These
loops
are connected together on the roof. The isolators are about 4 inches
high.
Tune up procedure is easy; Switch the TU to the correct frequency
range
with bandswitch on TU in radiocabin. Turn the variable vacuum C
until
maximum current is observed on the meter on the TU. System
ready for
use. It's a real quick system !
Practical performance ....Well, I can tell you this was a killer
antenna for
NVIS on 80m ! With 30Watts CW from the Russian trx I was
bending
S-meters all over Holland, HI.
The radio truck also has a vertical for long range tactical comms on
HF
and a shorter vertical for VHF. It also has a mast for
HF-dipoles
(with open feeders !).
Verticals and dipoles are tuned via a separate ATU. The stuff looks
old
fashioned but it works FB and the truck also has a crypto-unit.
As you can see the Russians had a pretty good setup, with great
flexibility. Hope you enjoyed the info.
73, Rob - PA3EQB
Visit the SRS-website
