You know that intermittent buzzing noise that the radio does.........

[Cattleprod]

...when you've placed your mobile phone next to it and a text message arrives? Even when the radio function is switched off. I assume it's because the mobile signals and radio waves are getting a bit mixed up(?)

Why does the buzzing still happen sometimes when no message or call is being sent or received? Does this mean that mobile phones still receive or emit signals at random points even when the phone is not being used?

My alarm clock radio is currently going crazy on the bedside table from the phone next to it. I keep getting excited thinking someone is texting me, but sadly not!

Can anyone explain the mystery?

I think there's a regular ping goes OUT to phones in each cell and the phone responds (ie not to do with calls or texts). Might be what you are hearing.

Makes sense , otherwise how is that info picked up in missing persons enquiries?

Are you sure you haven't just got old and are accidentally listening to Radio One?

I accidentally listened to R1 recently. I'm having therapy and am spending up to 2 hours a day without my ear plugs in - slowly but surely I'll build up to a whole day.....

(is bluetooth switched on? it might also be a nearby phone, not necessarily yours)

Even when a fone isn't recieving a message or taking a call it still needs to communicate with the transmitter so that if you were to make or receive a call it knows your location. It's called location area update.

For example if you are close to one mast then you are "on" this and the phone intermittedly sends a signal to the mast saying "I'm here if you have a call for me" if you then walk away from this mast towards another one, eventually the your fone will send out message, in simple terms saying "I'm here" and the 2nd mast will pick up that signal as you are closer to it, and you will then be "on" thattansmitter until you move again.

It's how police can track your location without you actually making a call

If that doesn't make sense, just say and I'll try again (am 3G radio engineer)

Known to DD as the electric chicken...

That makes sense geordie - so when someone calls or sends a text it makes it easier and quicker if the network already knows the location of the receiving phone.

So do the police or mobile companies keep a record of where everyone has been? Or does it just enable them to put a track on a specific mobile when, for example, someone goes missing?

Clarnico no, I've been a radio 2 listener for many years now - the dial never ventures towards radio 1 or Talk Sport.

It's easy to think of it as a daisy chain, handset to nearest mast to switching site.

Theoretically yes, mobiles cam be located within a mile or 2 at any given time, but due to the volume it's not like "xx is here" it's just data that would give the IMSI (or TIMSI I forget which) which is your fones unique id number and the sector and id of the mast that you are on, and the signal strength would determine how close or far away you are.

Different rooms in the house have 'dead spots' for different networks. PAYG phones on Asda (Vodafone), VM and Orange, so if I put the 9 phones I can see near an FM radio, would hear lots of noises! (and there are a few other phones in my other computer room). Good that T-Mob + Orange cells can handle both networks' phones now.