MP3 Transmitters Now Legal In the UK

SilentOneNCW writes "From December 8th, it will be once more legal to own and operate an MP3 Transmitter in the UK, primarily used to convey music between an MP3 player such as Apple's iPod to your home or car stereo. The device was originally banned because their transmissions can override and interfere with legal radio stations, which is prohibited by the Wireless Telegraphy Act of 1949. Strong consumer demand for the devices and pressure from Liberal Democrats were among the primary motivators for the amendment."

Re:Here in the US

[Nasarius]

That's the point; they broadcast on a frequency that can be picked up by your car radio. But the power is so low that it's unlikely to travel far outside your car.

Re:That's Too Bad

[ISurfTooMuch]

No, most all of them can be tuned to any frequency in the FM band. The ones like the Belkin TuneCast and the iTrip are within the legal power limits. Units made by companies like Ramsey (do a search for Ramsey FM10) are theoretically legal, as long as you don't use a transmitting antenna with too much gain. So, if you really wanted to, you could get one of these, add the proper (or improper) antenna, and easily exceed the allowed power output for an unlicensed transmitter. Not that I'm recommending this, you understand. I'm just saying that it can be done.

Part 15

[Kadin2048]

It's a power-level issue. The FCC allows unlicensed transmitters under Part 15; the maximum allowed varies with frequency. You can see the limits on this page [arrl.org]. For example, above 960 MHz, unlicensed devices can transmit a field strength of up to 500 microvolts/meter, measured at three meters from the radiating device. (Those units seem a little odd to me, but that's what the table lists.)

Part 15

[EricJ2190]

In the U.S. these FM transmitters are allowed by Part 15 of the FCC rules. The power output of the transmitter must be very limited to prevent interference. I am not sure what other countries have equivalent laws.

Re:As a UK resident

[ISurfTooMuch]

Actually, the BBC has a story on it. That's where I read about it. http://news.bbc.co.uk/2/hi/uk_news/politics/617782 0.stm [bbc.co.uk]

It's an FM transmitter, not an MP3 transmitter

[Animats]

At first I thought this was something for transmitting MP3 files around, but it's just a low-power FM audio transmitter to transmit to nearby FM radios. Those things have been around for decades, all the way back to 8-track players and drive-in movie theaters. All the TVs at my gym have one, transmitting on different frequencies.

If you're in a major metropolitan area where all the FM broadcast slots are in use, you may not have much success with one of these things.

Re:Here in the US

[oakgrove]

The volume of your ipod doesn't effect the loudness coming out of *your* transmitter precisely because you are using the line out that is built into the dock connector input on the bottom of your ipod which has a constant volume regardless of how you have the volume of the headphone output set. You can actually use a transmitter connected to the headphone out and have the headphone out set lower than the line out would have been thus using less battery power than you would using the line out. So on this point you are in fact wrong.

Only some of them will be legal!

[HuskyDog]

As it says in the BBC article [bbc.co.uk], only some devices will be legal.

Now certain FM transmitters, which can be tuned to spare frequencies, will be legal from 8 December.

However, many devices currently on the market will remain illegal as they do not meet the legally required technical specifications and could interfere with radio broadcasts.

All approved transmitters will carry a CE mark indicating approval for sale in the European Union.

So, as I see it, legal transmitters will not only have to meet strict power limits, but also be tunable only to certain spare frequencies in the FM band. I spent some time searching the Ofcom web site to try and find exact details of the regulations (e.g. which frequencies exactly), but without success. If anyone else can find them then I for one would be interested.

Detach car antenna for better reception

[mrb000gus]

My FM transmitter broadcasts on 88.2-88.9. Driving between midlands and London, in the UK this is Radio 2's regional frequency range, so throughout the journey Radio 2 kept kicking in and forcing me to change the FM transmitter's frequency and adjust the car radio.

One way to fix this is to detach the aerial from the roof of your car, it should still receive your FM transmitter's signal but not get interference from FM radio stations.