Government bodies which police the use of radio frequencies in Britain
are being put in an embarrassing position by a device which converts the
output of portable CD players into a low-power radio signal that can be
played through a car stereo. Although these gadgets cause no harm, the letter
of the law prohibits their use. The BBC has already given similar equipment
to schools, where it has been used without problems for a year.
Japanese electronics company Pioneer is promoting the system with full-page
colour advertisements in magazines. It allows anyone with a VHF stereo car
radio and a portable CD player to hear CDs through the car鈥檚 loudspeakers
and avoids the need to install a CD player in the car where it may attract
thieves.
Pioneer鈥檚 system relies on a modulator which functions as a miniature
radio transmitter. It connects to the output of a portable CD player and
imposes the audio signal on a radio wave whose frequency falls within the
VHF band used for FM stereo broadcasting. The modulator can be switched
to a number of frequencies around 88 megahertz, at the bottom end of the
band where there are unlikely to be any conventional broadcasts.
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Pioneer鈥檚 modulator comes in a small holdall with three leads and room
for the portable CD player. One lead plugs into the car鈥檚 cigarette lighter
socket, to provide a 12 volt DC power supply for the player. Another clips
onto the car鈥檚 aerial to feed the CD鈥檚 VHF signal into the radio. The third
has a remote control at the end with which the driver controls the CD player.
Sound quality is as good as the radio permits.
The Department of Trade and Industry and the Radiocommunications Agency
use the Wireless Telegraphy acts to stop anyone transmitting on frequency
bands reserved for entertainment broadcasting.
Pioneer鈥檚 CD transmitters cannot cause interference in these bands,
even to other cars, because the power of the modulator is so low that it
must be connected directly to the car radio aerial. The DTI and RA have
leeway to grant licence exemptions for very low-power devices. But they
say they must first draft a technical standard for the general type of device
and examine any device before sale for 鈥榯ype approval鈥�. They may then issue
an exemption licence for anything which passes the type-approval tests.
A representative of the DTI said last week: 鈥楾he Pioneer device is not
legal . . . we haven鈥檛 approved it. Pioneer have not approached us. There
is no technical standard, so there can鈥檛 be type approval and exemption,
even if they had applied, which they haven鈥檛鈥�
If the DTI bans the new in-car gadgets it will also have to ban similar
devices which the BBC has already supplied to schools. Last August the BBC
switched its schools education broadcasts from VHF FM to Radio 5 on the
medium wave. Several hundred schools had only FM receivers, and so could
not receive the BBC鈥檚 programmes any more.
The BBC designed a retransmitter which receives radio signals on the
medium wave and transmits them at low power on frequencies at the bottom
end of the VHF band. The school puts the retransmitter near the aerial of
its VHF receiver and tunes it to the output frequency.
The BBC thought it was on safe legal ground and did not seek formal
approval for its retransmitter because it connects directly to the aerial
socket of a receiver. Every domestic video recorder also has a low-power
modulator to connect it with the TV set through its aerial socket. So if
the DTI bans Pioneer鈥檚 and the BBC鈥檚 modulators, it will also have to ban
the video recorders in 70 per cent of British homes.
