Outside the PMRExpo exhibition hall, Ray Mason of Airwave in the UK and Steve Rolfe of Axell Wireless demonstrated the latest refinement of Airwave’s Emergency Response Vehicle (ERV) concept.

A small fleet of these vehicles – three generations of them – is on standby around the UK to bring temporary TETRA radio coverage to locations such as underground stations if called upon, and to help in natural disasters such as floods.
“This one is built for the German market”, explained Steve Rolfe. “It uses many of the features of the UK ERVs – including an Axell Wireless digital repeater – and we’ve got all the usual things (mast, generator, inverters, battery packs) so that we can run the vehicle for round about ten days, unsupported.”

During PMRExpo, the vehicle and its crew provided demonstrations showing how coverage could rapidly be deployed in a nearby railway underpass. “We can just put the mast up, tune into the donor site and then go down with some co-ax and a little panel antenna”, said Ray Mason. A week earlier, he added, the vehicle had taken part in a trial on the Berlin Metro, with participation by police and fire officers.

Though the ERV’s primary purpose is to deliver flexible TETRA coverage through its repeaters, antennas, cable reels and other on-board equipment, a key part of Airwave’s design philosophy is to safeguard the vehicle itself. “You’re never sure what’s going to happen”, Mr Mason pointed out. “Secondary devices... walls could fall down.”

So the vehicle carries a variety of AC and DC power options, including reconfigurable 12V and 24V batteries and various methods of recharging them – including, as a last resort,an independent petrol-powered portable generator. “If there’s an emergency and the crew go to a site and something is wrong, some faults, there’s always a workaround, so they don’t have to go away”, said Steve Rolfe.

The main electrical generator is supplied by the vehicle’s diesel fuel tank, which can be refilled without shutting it down. “The take-off pipe to the generator doesn’t go all the way to the bottom of the fuel tank”, said Ray Mason. “So the generator will stop and I’ve still got 20 litres of fuel to get away.”

Among the technical stores aboard the vehicle are a spare repeater and a five-metre mast, which enable a secondary installation to be provided if required. Further communications options can include optical fibre connections and VSAT backhaul via a dish mounted on the roof.