Mission Critical: Keeping in Touch.

The communications demands of special forces are exacting. Their operational roles dictate that they have to operate behind enemy lines, yet remain in touch with their base at all times to pass the intelligence and other data that is the very reason for their operational existence and among the most fragile of military commodities.

During a mission, special forces may have to operate using a wide range of communication capabilities. At one instant a special forces team may be contacting another team nearby and then transmitting to a far distant command centre. Then they may have to switch to talk to strike aircraft flying overhead or direct a helicopter to a pick-up point. At times it may be necessary to eavesdrop on enemy frequencies to determine what they are up to. During all this signal traffic, transmission times have to be kept as short as possible to prevent an enemy detecting the transmission location while message encryption is often necessary. For extra security, frequency hopping may be desirable, with message segments being broken up to be transmitted at different frequencies, to be joined up again at the receiving point. At times messages may have to be sent without using speech at all, such as when in close proximity to an enemy; recourse may then have to be made to transmitting short `blip' signals in prearranged codes.

If all this were not enough, communications hardware has to be as compact and light as possible while requiring a minimal power supply to run. It has to be easy to operate and maintain, while remaining rugged enough to absorb hard knocks and the occasional prolonged submersion in water. During air transport it has to be accepted that unpressurised cabins will be the norm. And by the way, the associated antennas have to be kept as small, unnoticeable and hassle-free as can be devised.

It is this wide spectrum of operational requirements that means that special forces communications equipment has to be very special. Run-of-the-mill military communications systems already have to be very robust and versatile but they are usually dedicated to precise operational tasks such as inter-unit communications over a set and limited frequency band.

Anything larger than a backpack load will usually be rejected as handheld radio sets are now the only ones deemed acceptable for all but the longest range functions. A measure of how this can be possible is the general acceptance of the mobile telephone by all and sundry. Soldiers now expect similar communications devices to fulfil their operational needs even though it would be most unwise to depend on commercial telephone networks under battle conditions.

In the same way, it is not always possible to rely on satellite communication systems. Yet once the direct line-of-sight VHF frequencies are no longer usable due to local terrain conditions or the distances involved, satellite-based communications are often all that are available, unless the detection risks of bouncing signals around the ionosphere are accepted. Yet due to a general acceptance that in time of war communication satellites may not remain operational for long, and due to the numerous variables that can naturally interfere with radio communications, the smaller and less powerful hand-held sets may often have to be replaced by larger back-pack or vehicle-mounted sets with their large antennas and other accessories. Dish antennas become necessary when long range UHF and SHF frequencies become involved, although the hardware involved is usually smaller than the antennas needed for the lower HF frequencies. UHF and SHF radios are highly directional in operation so signal interception becomes less likely than with the lower frequencies. This is just as well, for frequency-hopping to disguise message content becomes technically impossible at the higher radio frequencies. Apart from using these directional modes there is always the chance to reduce transmission detection still further by utilising `burst transmission' techniques. For this a data message is inserted into a receiver via a miniature keyboard, before transmitting the entire message in a brief burst lasting less than one second.

What special forces expect from their communications equipment has already been outlined but it has to be accepted that no one radio is ever going to meet every possible specification thought necessary. There are a few that seem to come close, one being the Racal Communications Multi-band Inter/Intra Team Radio (MBITR), in service with the US Special Operations Command as their AN/PRC-148. This remarkable little hand-held radio weighs less than one kilogram but can transmit and receive voice and data messages over a frequency range from 30 to 512 MHz, rendering the MBITR interoperable with virtually every type of radio in the military spectrum. Two versions are available, both having an encryption facility. One is a 20 m submersible version while the other is submersible to 2 m. Known users of the MBITR include US Navy Seals and the Australian SAS -- an `exportable' version is now available.

To avoid repetition, mention of one specialised equipment produced with special forces in mind can be made. This is the Israeli Tadiran Airborne Search and Rescue (Asars-G) with an integral Global Positioning System (GPS) capability. Special forces personnel can use the small, ground-based, hand-held radio components of this system, the PRC-434G, to inform a pick-up aircraft or helicopter of their exact location in addition to the search and rescue beacon function. Numerous applications for such a capability can be imagined. Asars-G has an over-the-horizon range of hundreds of kilometres and is so accurate that the incoming aircraft can use an on-board map-type display to be directed to arrive exactly over the special forces personnel involved.