JAMMING by Rimantas Pleikys
OLEG MAKSIMENKO REMEMBERS
According to Oleg Maksimenko, former shift-leader of the Vilnius jammer ("Object
No. 600"), the twelve KV-5 transmitters that were in operation
at the jamming station until 1976, were divided into two groups of six transmitters each.
Each group of transmitters was controlled by one operator. The operators were managed
by the shift-leader. Two other operators worked at the control and correction post
and were assigned control of each transmitter group. CCP and the jammer were connected
by two direct link (dedicated) telephone cables, approx. 7 km in length, with two
terminals on each end. CCP issued orders to the jammer operators to switch on a
particular transmitter to a particular frequency. The jammer operators never had a
chance to listen to what they jammed. After it was tuned in, the transmitter stayed
in heat-up (nakal) mode and the transmitter's RF stage was controlled
remotely from the CCP. According to other sources, the technicians used to put
a jammer on a particular frequency while listening to the frequency's performance at
the control post: the relevant zero-beat audio signal was supplied to
them from a communications receiver
via a telephone line from the CCP (It is quite possible that this system was used until
the mid 1970's when the old KV-5 transmitters were replaced with new
VIAZ type transmitters with synthesised exciters).
The Vilnius jammer CCP was headquartered one floor above the
Central Food Market, Gedimino str., and later in the premises of the State Radio
Frequencies Inspectorate (Žvėrynas district, Vytauto Street 20) until
1980 when it was moved to the administration building of the Radio and Television
Center (Karoliniškės district, at the TV tower).
The Kaunas CCP was on the 6th floor of the Central Post Office and later
was moved to the long-distance telephone exchange.
The staff of the Radio and Television Center usually referred to the
jammer as the "transmitting department". The call signs of the jammer were
transmitted to each transmitter currently in operation two times per minute
and twice each time. The Morse signal was produced by a simple device: a disk
driven by an electric motor which connected particular contacts into a short-circuit
every 30 seconds. The jammer personnel called it a "mashinka".
The letters also referred to as ID-codes were assigned to the
jammers in order to enable the CCP operators to identify each individual
transmitter (or jamming station) and to gauge its performance. In the Soviet Union,
groundwave jammers had the ID codes assigned in a two-letter or
a-letter-and-a-numeral format (rarely encountered). All the transmitters had
the same ID-code. The transmitters of the Vilnius jammer had the
"BL" ID-code initially, and was later replaced with the "LM"
ID-code (15 transmitters, of 5 kW power each).
Long distance skywave jammers possibly also had the ID-codes
assigned to individual transmitters (within the range of 20-200 kW).
The frequencies to be jammed were communicated from Moscow via teletype (acording
to O. Maksimenko, the HF RTTY point to point link was also used for this
purpose). The final decision concerning the jamming of a particular frequency
was adopted by the relevant CCP. It depended on the actual audibility of
the target station in Vilnius. "Object No. 600" employed a staff of 25 persons.
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