ZIL Radio Truck
In October 1999 I purchased what was advertised as a Zil Radio Truck. This ten tonne Russian military communications truck appeared to be well equipped and constructed with reasonable quality, contrary to military doctrine handed down to me whilst in service.
The MoD decided not to release any of the documentation they had received with the truck as many of the topics dealt with therein were still officially classified secret. Nor would they provide any history relating to where this truck came from.
Following a number of show events, those members of the MVT and similar organisations who also had an interest in radio frequently contacted me for more information relating to this truck, and some of the radio sets employed. Although I have put info onto my web site http://www.bellradio.co.uk/amateur.htm the requests keep appearing. I decided that the VMARS news letter may be a good platform to publish the next round of information.
The radio station is actually known as an R161. This number in fact relates to a series of trucks and equipment designed to provide a variety services. The large 161 stations are carried on no less than three trucks and have a staggering 15Kw RMS Tx power output. The first section of the following article deals with this larger system. The information has been translated from Russian without too much grammatical correction, and so it may not read as it would if written from English.
The purpose of the larger systems is to provide a communications backbone into which smaller and lower power stations can if needed Subscribe, although the smaller stations are capable of operating independently.
The Subscriber stations are designated R-161-A2M and it is the latter which I obtained, and hence I am able to produce much more detail. I do not intend to discuss frequency hopping or encryption, nor do I intend this article to be technical in any way, it is simply a description of a Soviet communication system for which nothing was previously known outside of the USSR and latterly the MoD.
Automated Adaptive Mobile H.F. Radio Station
This frequency agile radio system provides the three goals of frequency hopping radio, these are 1, resistance to jamming, 2, resistance to direction finding, and 3, resistance to intercept. The transmission of telephone, telegraph, and data is assured under high random or intentional noise levels. Provision of a communications link is automatic, and will automatically adapt to the noise environment. The remote control of the transmitter vehicle is provided from the receiving vehicle.
The radio station consists of three equipment shelters or Kungs, carried on the truck chassis. The receiving shelter and the transmitting shelter are carried on a Ural 43203 chassis. The generator set is carried on a Kamaz 4301 chassis, and is intended to provide power to the transmitter unit only.
The shelters have heating and cooling systems built in to ensure the correct and comfortable environment for the operatives. There are two radio relay sets being part of the equipment carried. The radio relay is used to control the transmitting vehicle from the receive shelter (up to 25Km). The control link can also be made by data cable (up to 10Km). The trucks are also fitted with HF radio for communication whilst travelling in column.
These trucks provide the Back-Bone communications network for smaller 161 stations to act as Subscriber stations. These smaller units are describer later on.
Radio Station R161-A2M
The Kung is divided into three rooms. The rear most room is equipped with a 16Kw three phase petrol driven generator. This generator is vented with air intake and hot air exhaust via opening panels in the side of the truck.
This room also contains two large blower motor fan assemblies used to keep the main radio amplifier cool, and a 3Kw forced air cooled dummy load. The room also contains a mains input filter used when the truck is plugged into mains power available at workshop or other buildings, and a 30 amp battery charger used the charge the auxiliary batteries.
The centre room of the Kung houses the twin power amplifiers, and the twin antenna coupling units. The frequency split for both units is 30Mhz, and selection of the correct amplifiers and coupler combination is achieved automatically from the main operating console.
The forward room of the Kung contains the main operating console. This is equipped with two radio receivers, one Tx exciter, one frequency hopping control unit, one frequency hopping modem, one antenna tuning control unit, and the main console for selection of signal routing and antenna selection.
Above top left can be seen the main receiver designated R160P. This receiver is of modular construction, nuclear hardened and all solid state. There are multiple connectors at the bottom of the receiver. Two connectors are used to enter frequency programming data when the set is switched to remote control. This programming takes the form of a diode matrix located elsewhere in the system. One connector is used to rout audio from the receiver to various external equipment's, including loudspeaker, keyboard decoder, and modem. The receiver is multi-mode and includes AM, FM, USB, LSB, ISB, FSK, FFSK modes. There is a single aerial input on a coaxial lead, and the other coaxial leads permit the input / output of the 5Mhz internal frequency standard. These outputs are used in conjunction with the receivers frequency hopping capability. One unusual feature of the receiver, is that during system antenna tuning the receiver forms a balanced bridge with the exciter and selected antenna. The antenna tuning controls are then adjusted for a maximum dip in the meter reading. By using the exciter output which is only 10mW, antenna tuning can be undertaken without giving your position away during set up, or periods of receive only activity.
Top right can be seen the exciter unit designated Lazure. This is also nuclear hardened and of modular construction. Fully solid state and equipped to provide noise adaptive communication [ frequency hopping ] these radio sets are among the latest technology seen from the USSR. The connector pattern seen on the receiver is repeated on the exciter and provides the same functionality. Both sets can be seen above with their associated power supply units, which are in fact the same unit providing commonality of spares. The internal modules are also common to both sets. Those inputs and outputs appearing on modules which are used in the exciter but not in the receiver are simply terminated by dummy load. This practise suggests considered design during conception.
Top left can be seen the manual access and control for the antenna tuning. The unit is equipped with ten memory locations where favoured settings may be stored. Also presented are SWR alarms and trip resets, plus control over either working or tuning states of operation.
Top right can be seen the noise adaptive controller [ frequency hopping control ]. Designated the R016 this unit interfaces directly with receiver and exciter taking direct control over their operating frequencies. The controller utilises the main or base frequency set by the operator, and then uses ten sub frequencies to form the selection of frequencies to hop to. During frequency hopping the net synchronisation is achieved by data exchange between all sets suitably equipped and forming part of the net. The writer believes that the hopping rate is about 2 per second , but it is not known if the hop pattern is orthogonal.
The system permits single frequency simplex working, split frequency simplex working, and split frequency duplex working. The cover which is just in view on the far left covers an audio and system patch field. Suitable interconnection within the patch field will permit re-broadcast operation, and telephone to radio transfer ( telepatch ).
The truck may be deployed as a long term communication station providing radio and telephone communications between the rear and forward units. In its long term role the two sixty foot masts would be demounted and set up in the field using the steel guy ropes supplied.
The diagram below gives an indication of how the system would be set up with priority given to either HF or VHF working. In HF priority working the VHF Tx antenna would be a broad band dipole complete with built in ground plane. The VHF Rx antenna would be a wire connected via a balun then coaxial cable to the receiver antenna switch.
In VHF priority mode, the VHF antennas for both Rx and Tx are replaced with log periodic antennas. In both modes the HF antennas are 400 ohm terminated rhombics with the exception of a single 13m wire dipole. All HF aerials are fed using ladder feeder.
I hope you have enjoyed reading about the R161-5 series. The content represents twelve months of research conducted mainly over the internet.
By Joe Bell G4PMY, A Member Of The Vintage and Military Amateur Radio Society.