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UKR /RB

Microwave relay system UKR / RB, IM 23b; manufactured by Brown Boveri & Cie., Baden.

The microwave radio system UKR was developed from 1947 on by Brown Boveri Cie., Baden. It became the first „real“ microwave relay system of the Swiss army.

The station was introduced with the troops in 1954 and was used in the mountain communications network from 1957 on.

After voice encryption was retrofitted in 1969, the mountain sites with the UKR formed the backbone of the microwave relay network of the army (RSA), which was set up in 1974 to ensure communication between the national government and the army command / army corps.

Microwave communications system UKR / RB

Technical data

Power supply

Dimensions

Accessories

  • A 1.4 m parabolic antenna was used as the standard antenna for the mobile systems and a 1.8 m parabolic antenna for the systems in high-altitude mountain stations.
  • Voice encryption as add-on

directional antenna UKR / RB

Station material

The large microwave relay system was developed by Brown Boveri, Baden, after 1947 and went into production from 1952 to 1957. In 1969, a add-on for voice encryption was added to enable secured connections.

The entire system consists of five equipment cabinets, four of which are as tall as a man. The first cabinet contains the actual transceiver, while the second, smaller one contains the equipment for the service telephone channel, which the operating teams of two stations could use to coordinate and prepare for commissioning. The third cabinet houses the multiplexer, in which the various telephony channels were combined using time-division multiplexing / pulse position modulation. The fourth cabinet houses the demodulation, i.e. the individual channels are extracted from the mixed signal, which contains the various telephony signals after passing through the multiplexer, and assigned to the outputs or the correct receiver. The last lockable cabinet contains the key modules for voice encryption operation for all voice channels.

With the MK-21 multi-channel device supplied by Hasler AG, Bern, one telephony channel could be used for 12 telex channels.

The receiver is located at the top section of the transmitter-receiver cabinet.

UKR receiver UKR receiver

The controls for the transmitter are located roughly in the centre of the cabinet; the „trombone“, the frequency-determining variable focuser, can be seen at the top left.

UKR transmitter UKR transmitter

The controls and technology for the service telephone channel are located in a slightly smaller cabinet. The operator can make contact with the remote station using the connected microtelephone.

UKR service channel

The system was used as a UKR/f(ixed), for example in high-altitude mountain stations.

Alternatively, the 11-channel version RB 1111/m could be used as a mobile unit on an four wheel driven truck, with the 1.4 or 1.8 m mirror mounted on the vehicle roof.

UKR off-road lorry UKR in the vehicle

The system exists in different variants:

  • RB 2323: designed for 22 telephony channels, 22 channels equipped (1 channel for crypto operation)
  • RB 1123: designed for 22 telephony channels, 11 channels equipped
  • RB 1111: designed for 11 telephony channels, 11 channels equipped (mobile configuration)
  • RB 0711: designed for 11 telephony channels, 7 channels equipped
  • RB 0707: designed for 7 telephony channels, 7 channels equipped (combined channel rack KK 7 with 7 modulators and 7 demodulators)
  • RB 1000: System for relay operation only (consisting of two SE-990 transceiver racks)

Technical principle

UKR / RB block diagram

Tube configuration

The BBC magnetron „Turbator“ or MD10/2000 developed by BBC is used in the transmitter.

Development

In the immediate post-war period, a group led by the engineer H.J. von Baeyer, formerly with German Telefunken, developed a pulse-modulated 23-channel microwave relay station with the Brown Boveri's „Turbator“ slot magnetron as the core element, which operated at 1.9 - 2.1 GHz. The IM 23 station, which was completed around 1948, was too expensive and prone to interference to be introduced in the civil telecommunications sector.

At this time, however, the microwave relay network of the army and the air force was under construction. Due to its availability and improved security against interception, the decision was made in favour of the revised IM 23b station from BBC and not the competing system developed by ITT / Standard Telephon & Radio AG.

Field Use

The first sets of the UKR arrived with the troops in 1954 and the construction of the network of high-altitude mountain stations began around 1957.

UKR system at a high-altitude locationIn 1952, a first batch of 108 stations was ordered, with subsequent orders in 1956 and 1960, 187 stations were procured in the end. The army's microwave relay network (RSA) only became fully functional around 1974 with the retrofitting of a powerful encryption system in 1969. This was used for communication between the national government and the army corps; on site, users were connected to the radio relay network at „permanent connection points“ (PUA), which were ready for use from 1977. Thanks to mobile stations on off-road trucks, forward command posts could also be integrated into the army's microwave relay network. Around 1981, the previously hand-switched network was restructured in favour of fixed connections.

In 1990/4, the UKR systems were dismantled and replaced by the powerful solid state station SE-915.

Technical documentation

Further information

en/ukr.txt · Zuletzt geändert: 2024/01/09 19:17 von mb