Stuttering electronic interference

[mike ring]

I was just reading a Dect thread and it prompted me to ask if anyone can explain this.

Occasionally I get a strange stuttering interference, like a chopped buzz, with uneven mark/space ratios, like bzzz......bzz..bzz.....bzzzz, etc etc.

This appears to come in on everything, radio, telly, computer speakers, possibly the phones, but no-one ever calls...

Does anyone know what this is?

It doesn't do any harm that I can tell, and is fairly recent, I think, like months, not years.

I'm in mid Essex, a bit outside the M25.

It sounds intentional, but I can't imagine what it could be used for, perhaps a switching code or something.

???

mike

[Dave Jones]

Ham radio?

[brugnospamsia]

Da dit dah dit dah dah dit dah ?

(CQ)

[Andrew Chesters]

"Sounds" like a mobile handshaking with a node to me...

[brugnospamsia]

forgot about that

If you listen to interviews on "Today" in the morning you'll hear it all the time. (politicians wearing tie-clip mics with mobiles in their pockets)

reminds me to put a warning notice up in the small recording studio I run at work :-)

I keep meaning to record an example and upload it ...

[brugnospamsia]

does it sound a bit like this ?

22kbytes

(ancient Motorola / Orange pay as you go)

------------------------------

[bof]

In message , mike ring writes

If you've got a mobile it's probably just saying hello to the network, stick it near a computer monitor and you'll probably see bars on the picture at the same time.

[Dave Plowman (News)]

I have constant problems - I do location TV sound.

You'd think everyone would be aware of it - but no, even experienced talent arrive on set with their phone on silent. My favourite mic uses an RF carrier system to amplify the signal from the capsule, so may be more prone to this than others - although personal mics, which are generally unbalanced, are even worse. The phone has to be pretty close to the mic to cause problems - the rest of the chain is fairly immune.

Interesting when you say a re-take is necessary and why. The looks of guilt from those who have a phone on set. But hopefully, everyone takes their phone out to look at it at the same time, and by slight of hand, switches it off. :-)

Incidentally, some networks seem worse than others - although I suppose it depends on the area and how close the base stations are.

[Jeff]

Dave Plowman (News) wrote :-

Thats probably because of the different frequencies - just noticed my mobile knocks my mouse out of sync with its charger basestation ( been blaming the kids for months )

Regards Jeff

[bof]

In message , "Dave Plowman (News)" writes

The phones seem to do different handshakes as well, having just changed to a Sagem after years on Nokias, the new buzz pattern was a little disconcerting.

[Mark Carver]

Voda/O^2 900 MHz [1]

T-Mobile (and virtual networks Virgin and Fresh) and Orange 1800 MHz

[1] Voda and O^2 do additionally use 1800 MHz for 'micro cells' (shopping centres, inside buildings, etc)

[brugnospamsia]

I suspect the "carrier" frequencies /per se/ are fairly irrelevant, but I reckon there will be some one out there who could say which network you were using - just like those acts who could identify the music by looking at a vinyl record .....

I worry sometimes about the sheer amount of high frequency radiation about the place - even my doorbell runs on 1.2GHz

[Jeff]

brugnospamsia wrote in :-

Yes, as anal as it may seem I made a decision a few years ago to swap from orange to voda for that reason

Regards Jeff

[Mike]

Apart from electrets and radio mics, I would have thought it was the actual mic amp that was most likely to cause the problem by rectifying the r.f. Some equipment does offer front end filtering to reduce this though not always totally effectively. Always good to walk round PLASA with a phone hidden in your hand.

[Mike]

Not anal at all. I'm sure Orange always gave me a headache after more than

20 minutes on the phone.

[mike ring]

"brugnospamsia" wrote in news:_jmXd.256$ [e-mail]:

THAT'S THE BUGGER!!

But my mobile's never switched on! I mean that - it's only for motorbike emenrgencies, I haven't found another use for it, and touch wood, not done it's primary function.

I *knew* I'd asked in the right place.

But I've never heard it on my phone on my occasional phones to my answering machine to keep my account alive.

mike

[mike ring]

"brugnospamsia" wrote in news:BlnXd.309$ [e-mail]:

Does your dog answer it?

mike

[The Natural Philosopher]

Mobile phone? Radar station? Microwave Oven?

[Andrew Chesters]

What about family or neighbours? Or do you live under a base-station?

[Dave Plowman (News)]

Well, the area where the mic amp (mixer) is situated is under my control, so I'd kill anyone who hasn't switched off their phone. Apart from me, obviously.

Don't need to. Motorolla walkie-talkies will zap anything.