mobile (cell) phone jamming

[Steve Terry]

"Gordon Brown" <.> wrote in message
news:3fe9fd77$0$13354$cc9e4d1f@news-text.dial.pipex.com...

"Steve Terry" <g4wwk@despammed.com> wrote in message
news:TUmGb.10018$526.67485@newsfep4-glfd.server.ntli.net...
The whole point of the phone operating on a 45MHz split with odd phased
time slots is so the phones RX doesn't hear it's TX.
Upset any part of that cycle with a relatively low signal, and the phone
stops
working.

So what sort of delay would be necessary and to what tolerance?

A few microsecs ?

I would guess interfere with as little as 20% of the slots to stop the phone
working

If there is already a random element in the slots maybe just letting the
phones RX see it's TX with a nearby 45MHz mixer osc could be enough ?

Steve Terry

 

[Ken Taylor]

"Ken Finney" <kenneth.c.finney@boeing.com> wrote in message
news:HqDFEw.B1p@news.boeing.com...

"Ken Taylor" <ken123@xtra.co.nz> wrote in message
news:bsag78$bafgl$1@ID-76636.news.uni-berlin.de...
"Paul Burridge" <pb@osiris1.notthisbit.co.uk> wrote in message
news:6fghuvguul35vq36on1nmc1n0mf3tf5jub@4ax.com...
On Tue, 23 Dec 2003 21:30:57 +0000, John Woodgate
jmw@jmwa.demon.contraspam.yuk> wrote:

I read in sci.electronics.design that Ken Taylor <ken123@xtra.co.nz
wrote (in <bsa80k$b752k$1@ID-76636.news.uni-berlin.de&gt about 'mobile
(cell) phone jamming', on Wed, 24 Dec 2003:

What's the difference whether I'm talking to a person in the flesh
or
via a
piece of plastic and metal.

It's not the phoning that's annoying, it's the loud voice, which is
quite unnecessary but we've got used to it through using ordinary
phones. Ordinary phones have 'sidetone' anyway - you hear your own
voice
in the earpiece and that helps to control your own voice level.
Mobile
phones DON'T HAVE SIDETONE, which is a bit of a surprise when you
first
realise it. WHY they don't have it, I don't know; maybe the small
dimensions mean that a usable level of sidetone results in acoustic
feedback. But a mobile with sidetone might eliminate the annoying
VOICE
LEVEL.

Agreed. That's the nub of it. And there are still a lot of folks
around who seem to think if the person they're calling is a long way
away, they need to shout even louder!

Aint that the truth! I'll go along with that argument - discretion is
such
a
poorly rated virtue.


And, for some reason, people on a phone forget they are in a crowd.
Nothing like being in a public venue and having someone shouting into
their phone, discusing someone stool sample (true story).

Yeah, I hate furniture salesmen too.

Ken

 

[Zak]

Steve Terry wrote:

If there is already a random element in the slots maybe just letting the
phones RX see it's TX with a nearby 45MHz mixer osc could be enough ?

Well, if you build a PLL it should not be too hard to keep it running
in the channel for the moments that the reference signal is off.


Thomas

 

[Steve Terry]

"Zak" <spam@jutezak.invalid> wrote in message
news:cWnGb.4654$7U1.57801@amstwist00...

Steve Terry wrote:

If there is already a random element in the slots maybe just letting the
phones RX see it's TX with a nearby 45MHz mixer osc could be enough ?

Well, if you build a PLL it should not be too hard to keep it running
in the channel for the moments that the reference signal is off.
Thomas

Shouldn't need the complexity, phones only just manage not RX their own TX

45MHz away under normal conditions

Steve Terry

 

[Gordon Brown]

"Steve Terry" <g4wwk@despammed.com> wrote in message
news:XwpGb.10190$FN.7538@newsfep4-winn.server.ntli.net...

"Zak" <spam@jutezak.invalid> wrote in message
news:cWnGb.4654$7U1.57801@amstwist00...
Steve Terry wrote:

If there is already a random element in the slots maybe just letting
the
phones RX see it's TX with a nearby 45MHz mixer osc could be enough ?

Well, if you build a PLL it should not be too hard to keep it running
in the channel for the moments that the reference signal is off.
Thomas

Shouldn't need the complexity, phones only just manage not RX their own TX
45MHz away under normal conditions

The GSM downlink and uplink bursts are spaced 3 burst periods apart, with
the downlink burst occurring first. This means that (in the case of
frequency hopping enabled) the GSM mobile will be receiving and transmitting
on Channel A before moving on immediately to a different channel from its
next reception and transmission. In this case, I doubt such a simple
"delayed-feedback-interferer" would actually jam a GSM mobile station in
practice under normal conditions .

 

[nemo]

Nomen Nescio <nobody@dizum.com> wrote in message
news:19753618175c418dbc95486d62b0408b@dizum.com...

According to an article in the Register, Anil Vora has invented a
handheld phone jammer for about Ł30.

http://www.theregister.co.uk/content/archive/7284.html

But I can't find his company. Anyone know how to buy one of these?

Build a pocket-size spark transmitter with a stripline tuned circuit tuned

to the centre of the Foe Bile Moan band. Insulate it well though - otherwise
it could be painful!

It's not very well known that very early experiments with spark transmitters
produced emissions at UHF and SHF frequencies.

Nemo the Newbie - to here - not to electronics.

 

[nemo]

Jaime <usernet@jaimem.org.uk> wrote in message
news:ClEEb.2862$tQ6.35256@wards.force9.net...

According to an article in the Register, Anil Vora has invented a
handheld phone jammer for about Ł30.

http://www.theregister.co.uk/content/archive/7284.html

But I can't find his company. Anyone know how to buy one of these?

To quote from the link:

"And while it may be legal to buy Mobile Squelcher, it is certainly
illegal
to use it -- in the UK, at any rate, where authorities discourage
broadcasting on unauthorised airwaves through hefty fines."

Which is probably why no one is bothering to sell them.

Jaime

They've gotta catch yer first! And if they detect it they'll probably think

it's just QRN or accidental QRM.

 

[George Orwell]

"Gordon Brown" <.> wrote:

"George Orwell" <nobody@mixmaster.it> wrote in message
news:b57deee82064347349787c2cd5202d22@mixmaster.it...
"Gordon Brown" <.> wrote:
That's what I was thinking. This would be a lot simpler than having to
detect a specific signal, modulate it by 45MHz an retransmit it.

Would the white noise across the right frequency band confuse the
phone enough to disconnnect or garble the call?

I am no RF engineer, but IIRC, building a broadband transmitter
intentionally is not that simple. Also the noise will have to be above the
signal from the base station transmitter (say 50W transmitter?). I wonder if
it would not be easier to jam the uplink signal as this would only require
the jammer to transmit in the same order of power as the mobile.

This sounds promising for technical reasons (simplicity,
effectiveness, ease of use) BUT the jammer would have to produce as
much output power as the phone -- this would make it much easier for
"the authorities" to locate the jammer.

How much power at a short distance (I think the OP said a few yards)
would be required to overpower the cell's signal to the phone
(powerful but much more distant)?

 

[starwars]

"nemo" <nemo@naughtylass2.wet> wrote:

Nomen Nescio <nobody@dizum.com> wrote in message
news:19753618175c418dbc95486d62b0408b@dizum.com...
According to an article in the Register, Anil Vora has invented a
handheld phone jammer for about Ł30.

http://www.theregister.co.uk/content/archive/7284.html

But I can't find his company. Anyone know how to buy one of these?

Build a pocket-size spark transmitter with a stripline tuned circuit tuned
to the centre of the Foe Bile Moan band. Insulate it well though - otherwise
it could be painful!

It's not very well known that very early experiments with spark transmitters
produced emissions at UHF and SHF frequencies.

Interesting idea!

 

[Chay]

What is your application, how many units are you looking for, how soon do
you intend to acquire and what is your budget?


"starwars" <nobody@tatooine.homelinux.net> wrote in message
news:de013055de2e0607500aa19821d9009a@tatooine.homelinux.net...

"nemo" <nemo@naughtylass2.wet> wrote:


Nomen Nescio <nobody@dizum.com> wrote in message
news:19753618175c418dbc95486d62b0408b@dizum.com...
According to an article in the Register, Anil Vora has invented a
handheld phone jammer for about Ł30.

http://www.theregister.co.uk/content/archive/7284.html

But I can't find his company. Anyone know how to buy one of these?

Build a pocket-size spark transmitter with a stripline tuned circuit
tuned
to the centre of the Foe Bile Moan band. Insulate it well though -
otherwise
it could be painful!

It's not very well known that very early experiments with spark
transmitters
produced emissions at UHF and SHF frequencies.

Interesting idea!

 

[starwars]

"Chay" <caatalyst@comcast.net> wrote:

What is your application, how many units are you looking for, how soon do
you intend to acquire and what is your budget?

I want to build one small (handheld), battery-powered, mobile
phone jammer for personal use, so that when I'm on the bus/train
and some idiot starts loudly talking about his business, I can
cause just enough interference to disconnect him mysteriously.

I want very short range (no more than 5 meters) and it would be
nice if it had a little bit of directionality. I don't want to
aim it at someone but it would be nice to be able to disconnect
the loud phone user in front of me without affecting the text
messager behind me, for example.

Given the short range that I want, I think very low power would
be required, so it shouldn't be expensive and it should also
reduce the chances of getting caught. (I already know this is
technically illegal.)

 

[Jon]

starwars posted the following for all to hear...

I want to build one small (handheld), battery-powered, mobile
phone jammer for personal use, so that when I'm on the bus/train
and some idiot starts loudly talking about his business, I can
cause just enough interference to disconnect him mysteriously.

I'm sure that's illegal under the wireless telegraphy act.

I want very short range (no more than 5 meters) and it would be
nice if it had a little bit of directionality. I don't want to
aim it at someone but it would be nice to be able to disconnect
the loud phone user in front of me without affecting the text
messager behind me, for example.

I suggest you need some professional help if somebody having a
conversation in your vicinity causes you so much agro. Sure it's
annoying but get over it.

Given the short range that I want, I think very low power would
be required, so it shouldn't be expensive and it should also
reduce the chances of getting caught. (I already know this is
technically illegal.)

There's nothing "technically" about it - it is!
--
www.unlockingshop.co.uk
change 'spam' to 'info' to email
SonyEricsson T610 unlock/unbrand - Ł15
Sagem DIY remote unlocking available - see site for details
Motorola Remote Unlocking still available - Ł15

 

[Ivor Jones]

"Jon" <spam@unlockingshop.co.uk> wrote in message
news:MPG.1a8c2fbd1f57f873989806@news.cis.dfn.de...

starwars posted the following for all to hear...
I want to build one small (handheld), battery-powered, mobile
phone jammer for personal use, so that when I'm on the bus/train
and some idiot starts loudly talking about his business, I can
cause just enough interference to disconnect him mysteriously.

I'm sure that's illegal under the wireless telegraphy act.

It certainly is..!

I want very short range (no more than 5 meters) and it would be
nice if it had a little bit of directionality. I don't want to
aim it at someone but it would be nice to be able to disconnect
the loud phone user in front of me without affecting the text
messager behind me, for example.

I suggest you need some professional help if somebody having a
conversation in your vicinity causes you so much agro. Sure it's
annoying but get over it.

A *short* conversation is one thing, but it can become annoying and
distracting if the person's voice is loud and the call goes on and on and
on and on and on and on and on and on...........!

I'm a bus driver and it's very distracting to have someone with a loud
voice organising their hectic social life for the entire duration of a 30
minute bus journey. Then they get off and we go back the other way and
somebody else does exactly the same thing..!

Aaaaaaarrrrgggggghhhhhh......!!!!!

Ivor

 

[michael turner]

On Wed, 04 Feb 2004 11:46:13 +0100, starwars wrote:

"Chay" <caatalyst@comcast.net> wrote:

What is your application, how many units are you looking for, how soon do
you intend to acquire and what is your budget?

I want to build one small (handheld), battery-powered, mobile
phone jammer for personal use, so that when I'm on the bus/train
and some idiot starts loudly talking about his business, I can
cause just enough interference to disconnect him mysteriously.

Illegal, (Wireless Telegraphy Act, 1949).

I want very short range (no more than 5 meters) and it would be
nice if it had a little bit of directionality. I don't want to
aim it at someone but it would be nice to be able to disconnect
the loud phone user in front of me without affecting the text
messager behind me, for example.

Wear a loud walkman with some really cheap-crap leaky headphones, and sit
right behind or in front of them. Tsss...ssss...ssss...tssss..

Alternatively eat a really smelly take-away near them, KFC or doner-kebabs
are quite effective.

Given the short range that I want, I think very low power would be
required, so it shouldn't be expensive and it should also reduce the
chances of getting caught. (I already know this is technically illegal.)

--
Michael Turner

 

[TCS]

On Thu, 5 Feb 2004 13:46:44 -0000, Ivor Jones <this.address@notvalid.inv> wrote:

A *short* conversation is one thing, but it can become annoying and
distracting if the person's voice is loud and the call goes on and on and
on and on and on and on and on and on...........!

So tell them to shut the fuck up!

I'm a bus driver and it's very distracting to have someone with a loud
voice organising their hectic social life for the entire duration of a 30
minute bus journey. Then they get off and we go back the other way and
somebody else does exactly the same thing..!

Aaaaaaarrrrgggggghhhhhh......!!!!!

Ivor

 

[Activeviii]

"TCS" <The-Central-Scrutinizer@p.o.b.o.x.com> wrote in message
news:t8KdnTgsctHoxb_dRVn-ig@comcast.com...

On Thu, 5 Feb 2004 13:46:44 -0000, Ivor Jones <this.address@notvalid.inv
wrote:
A *short* conversation is one thing, but it can become annoying and
distracting if the person's voice is loud and the call goes on and on and
on and on and on and on and on and on...........!

So tell them to shut the fuck up!

LOL.LOL. "Would the passenger on in the 5th row from the back, on the
right, with the mobile next to there ear...........SHUT THE FUCK UP!!!!"

PMSL.LOL

I'm a bus driver and it's very distracting to have someone with a loud
voice organising their hectic social life for the entire duration of a 30
minute bus journey. Then they get off and we go back the other way and
somebody else does exactly the same thing..!

Aaaaaaarrrrgggggghhhhhh......!!!!!

Ivor

 

[Ivor Jones]

"michael turner" <mike.turner1963@RemoveThisBitToReply.virgin.net> wrote
in message
newsan.2004.02.05.14.00.46.606000@RemoveThisBitToReply.virgin.net...

[snip]

Wear a loud walkman with some really cheap-crap leaky headphones, and
sit
right behind or in front of them. Tsss...ssss...ssss...tssss..

Alternatively eat a really smelly take-away near them, KFC or
doner-kebabs
are quite effective.

Not on my bus you won't..!!!

Ivor

 

[Eddie Haskel]

Sit next to the idiot and fart!

"Ivor Jones" <this.address@notvalid.inv> wrote in message
news:bvu74t$u39$1@newsg4.svr.pol.co.uk...

"michael turner" <mike.turner1963@RemoveThisBitToReply.virgin.net> wrote
in message
newsan.2004.02.05.14.00.46.606000@RemoveThisBitToReply.virgin.net...

[snip]

Wear a loud walkman with some really cheap-crap leaky headphones, and
sit
right behind or in front of them. Tsss...ssss...ssss...tssss..

Alternatively eat a really smelly take-away near them, KFC or
doner-kebabs
are quite effective.

Not on my bus you won't..!!!

Ivor

 

[Michael]

Coughing, sneezing and snotting work well

"Eddie Haskel" <wiseguy@clever.com> wrote in message
news:KAGUb.20773$5f.11160@newssvr27.news.prodigy.com...

Sit next to the idiot and fart!

"Ivor Jones" <this.address@notvalid.inv> wrote in message
news:bvu74t$u39$1@newsg4.svr.pol.co.uk...

"michael turner" <mike.turner1963@RemoveThisBitToReply.virgin.net> wrote
in message
newsan.2004.02.05.14.00.46.606000@RemoveThisBitToReply.virgin.net...

[snip]

Wear a loud walkman with some really cheap-crap leaky headphones, and
sit
right behind or in front of them. Tsss...ssss...ssss...tssss..

Alternatively eat a really smelly take-away near them, KFC or
doner-kebabs
are quite effective.

Not on my bus you won't..!!!

Ivor