Net gives pirate radio the last laugh

YOU are chilling out to your favourite songs on your car radio, only to have them drowned out by an appalling, fuzzy din you didn't tune into. It happens all too often in cities, where legitimate stations in the FM band lose out to pirate stations playing their own brands of music alongside brash nightlife advertising. And this hijacking of the airwaves won't change any time soon, thanks to the internet. So says airwave watchdog Ofcom, which manages and protects radio frequencies for the UK government. Ofcom cites two major threats in its annual enforcement report: keeping pirate stations off the air and preventing people buying and using illegal radio-frequency equipment designed to jam cellphones. In both cases, the internet is aiding and abetting "spectrum crime" - hijacking radio frequencies which broadcasters, including legitimate radio stations and cellphone companies, have already paid huge sums to use, says Ofcom. In the past, pirates would have put an unlicensed radio station on the air by fixing an antenna on the roof of a tall apartment block, connected to an FM transmitter close by. Essentially a large amplifier, the transmitter lets the antenna radiate a 200-watt signal covering a radius of a mile or so. About 20 years ago, says Paul Mercer, head of spectrum enforcement at Ofcom, the pirate's "studio" would be in the same building, but to evade arrest and seizure of studio equipment, they began using a radio link from a studio elsewhere, feeding their music across the rooftops to their transmitter, which rebroadcast it in the FM band. In the event of a raid, only the transmitter and antenna would be lost. Ofcom teams had no trouble picking up those studio radio links, in bands at 55 and 180 megahertz, because they were fairly broad and gave their presence away by interfering with other licensed radio services. So the pirates then switched to studio-to-transmitter links in the harder-to-detect microwave band, around 10 gigahertz. These are more focused and less likely to cause telltale interference. "So we then developed, or procured, equipment that lets us detect those microwaves, too," says Mercer. In addition, the focused directionality of microwave signals meant a visit to an illegal FM antenna would also reveal the microwave-receiving antenna. "And it will be pointing straight at the studio supplying the station's content," he laughs. Pirate radio is no longer such easy prey, thanks to the internet. "Illegal broadcasters are now seeking to distance their operations from the likelihood of enforcement action by streaming their broadcasts online," says Ofcom in its report. While people can listen to a legitimate web-based radio station, that same audio stream can also be used to get the signal via modem to a remote transmitter without using a (detectable) radio or microwave link. "Many have now replaced their radio link with the internet," Mercer says. Pirates aren't content with web-based radio because they want to reach the all-important street audience too. "Our research shows that most people listen to illegal broadcasters in their cars or on cellphones with FM receivers," he says. Even if a pirate's transmitter and antenna are seized, they simply redirect their internet audio stream to another transmitter/antenna on another building and carry on broadcasting. "Effectively, this allows pirate radio stations to be operated remotely," complains Ofcom. So taking them off-air only works in the short term. As an example, Ofcom cites a series of simultaneous raids on London's pirate stations in 2005. In that operation, 53 transmitters and 17 antennas were seized and illegal broadcasting was reduced by 57 per cent. Success was short-lived - over the following weeks, pirates crept back on air (see graph) until after a few weeks the number of illegal broadcasters crept back up to the pre-raid level. But Ofcom says those coming back on air are often new radio pirates taking up the frequencies - not those they have prosecuted, seen heavily fined or sentenced to community service. To combat pirates getting on-air, Mercer's team is "upskilling" - learning a new bag of internet and surveillance tricks that, for instance, let them track down the hosts of web radio audio streams that in turn may lead them to pirate broadcasters. Ofcom's big, probably impossible, dream is that pirates will migrate to the net and eventually ditch FM. The internet may also be responsible for other airwave problems. Ofcom says the "exponential growth" in websites selling illegal cellphone jammers is wrecking services carried on expensively licensed frequencies. Jammers create holes in cellphone coverage that lead to complaints from mobile phone networks which have paid billions for blanket coverage - and Ofcom found, for instance, that last year a Mosque and a theatre had installed them. Ironically, people afraid of cellphone radiation are major buyers of jammers - not realising that they work because they give off higher-energy microwaves than the phone itself. People afraid of cellphone radiation buy jammers, not realising they are sources of energetic microwaves Last year, Ofcom stripped 42 jammer advertisements from 19 websites and is prosecuting three vendors. By writing to those sites' customers, they have even managed to convince some buyers to surrender their devices. Others clearly love the peace and quiet their jammers give them. "Not everyone answers our letters," Mercer admits.

by Paul Marks