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G0FTD > SWL 20.04.05 06:52l 99 Lines 4867 Bytes #999 (0) @ WW
BID : D00459G0FTD
Read: GUEST DK5RAS
Subj: More Cold War Jamming 2/5
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Sent: 050419/1514Z @:GB7SXE.#38.GBR.EU #:28147 [Hastings] FBB7.00i $:D00459G0FT
From: G0FTD@GB7SXE.#38.GBR.EU
To : SWL@WW
Some of the broadcasters liked to be deceptive: Radio Beijing used to
change its frequencies slightly during the broadcast (frequency agility
method), leaving the hoarse choir of Soviet jammers aside. There were
several occasions recorded when R. Beijing played its Russian programs
backwards, and these particular frequencies were not jammed. Moscow
monitors would tape programs, play them backwards to make transcripts,
and submit the scripts to the KGB and Communist party bosses.
The jamming monitoring sites ("Control and Correction Posts") used to
be installed several kilometers away from the transmitting facilities.
The operators - mostly women - scanned the HF broadcasting bands.
It was their decision to start jamming, depending on the actual
audibility of the target station. Monitors issued orders by a dedicated
phone line to the transmitter personnel to tune a particular transmitter
to a particular frequency. All frequencies, times, station names,
program languages and audibility evaluations were entered in logbooks.
The transmitters sometimes were switched on remotely from the receiving
site. Vytautas Liatukas, a supervisor of Kaunas city jammer in
Lithuania, complained in a company paper back in 1975 about their
station "being in continuous shortage of filaments for radio tubes,
transmitter measuring devices, cabling, as well as about the poor
condition of the roof of the building and antennas." Some transmitters
were said to be in operation for as much as 20 years with no major
overhaul.
According to an old Soviet standard, masts of the jammers were painted
in yellow and black until 1975, to prevent enemy aircraft from
identifying them in the natural background. From about 1975 onward,
all the radio and TV towers, including jammers, were painted in white
and red. They have been illuminated at night with red non-blinking lights.
Every jammer used the same identification code, or call sign, for all its
transmitters, made up of two letters. The call letters of the jammer were
transmitted twice per minute for identification of each station.
Jonas Cepas, a veteran of the State Radio Frequency Service of Lithuania,
gave the following exclusive account: "We witnessed many problems
affecting TV and radio broadcasting caused by the shortwave transmitters
used to jam foreign radio stations. Various combinations of the signals
interfered with television and radio programs broadcast on long, medium,
and short waves, with radio communication and other radioelectronic
equipment.
The signals emitted by powerful transmitters made their way even to the
electric circuits of tape recorders and record players. Being aware of
the many heavy-duty transmitters operating near their residential areas,
people were worried about health hazards related to effect of the
electromagnetic field. Measurement data proved that the worries were
substantiated".
Thirteen long distance jamming radio centers with over 100 high power
(50-500 kW) short wave transmitters were used for blocking out large
territories by transmitting interference into specific region.
The operational distances of such sky wave jammers were 500-3,000 km.
The vertical curtain array and rhombic antennas were used for long
range jamming. Additionally, the USSR jammed from its territory the
Polish, Czech, Slovak and Bulgarian language programs of RFE/RL, VOA,
BBC and DW. Several secret cross-border jamming agreements were signed
between Moscow, Prague, Sofia and East Berlin. Romania and Hungary
participated in the cross-border jamming network until 1963-64.
There were 10 to 12 sky wave jamming centers in East Europe with over
90 transmitters.
Those who used to span the dial could often find "holes" in the
jamming wall. Twilight immunity was one of several technical methods
used for many years by the Western broadcasters to reduce jamming.
The twilight immunity makes use of broadcasting to the target area on
certain frequency on which the skywave jammer, placed a few thousand
kilometres to the East, cannot be effective for a given area because
of its lower maximum usable frequency at that time.
Roar of jammers smothered RFE/RL, VOA, BBC, DW, Voice of Israel,
R. Beijing, R. Tirana, R. Korea and R. Free Russia. Before 1963,
broadcasts from Vatican, Rome, Belgrade and Paris were jammed as well.
Several times, when the political climate became warmer, the USSR
would stop jamming government stations from London,Washington and Cologne:
* Six months in 1956, between Khrushchev's visit to Britain and the
Hungarian crisis.
* In September of 1959, during Khrushchev's visit to the U. S.
* In early 1960 until the "U2" incident
* June 19, 1963 - August, 1968 (Soviet invasion of Czechoslovakia)
* September, 1973 - August 20, 1980 (Martial law declared in Poland)
Continued in part 3...
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