magnetic field

Keith R. Williams · Sep 29, 2004

In article <rg19uv84pr760u8g2ajcsu594q1p12f825@4ax.com>, R75/5
@defaulter.net says...

On Sat, 20 Dec 2003 11:51:33 -0500, Keith R. Williams
krw@attglobal.net> wrote:

In article <p3l8uvso6ophb0ba3cure4v2l7lg2alcjj@4ax.com>, R75/5
@defaulter.net says...
On Fri, 19 Dec 2003 21:44:04 GMT, Bob Stephens
stephensdigital@earthlink.net> wrote:

On Fri, 19 Dec 2003 12:22:22 -0800, Paul Hovnanian P.E. wrote:

Tarapia Tapioco wrote:

I want to build a mobile phone jammer

* short range (not more than 5 yds)
* handheld, small
* battery powered

so that when I'm on the bus/train and some idiot start loudly talking
about his business, I can press a button and cause just enough
interference to disconnect him mysteriously.

What's the problem? If someone annoys me too much with a phone, I just
offer to jam it somewhere. Manually. ;-)

When someone annoys me by yakking on a cell phone in a restaurant, meeting
etc., I just join right in the conversation "Sure thing Bill. Friday's
great. Just don't bring that whiny annoying wife of yours..." etc.
I get some priceless looks.

Bob
Hey that's pretty good - worth a try.

Now, what is your technique for getting the woman on the road in the
SUV who is ambivalent about which lane she intends to use?

Bigger SUV with snow blade on front.
Well that wouldn't work for long . . .

You have no clue how well it works. Mommy in the SUV will never
have a blade. Mommy in the SUV is petrified of anything larger
than she. A blade trumps a thousand pounds!

The whole idea of SUV's seems to be the "i'm bigger and badder don't
mess with me," syndrome. Whimps with a need to assert themselves?

Hogwash.

Doubtless that will draw a firestorm - but rationalize all you want -
you know, deep down, I'm right about this . . .

No, I know you're an idiot and a slimy leftist-pinko-drugged-up
freak! SUVs have this little 'U' in the middle.

So soon we are all trucking around in 6 ton, gas guzzling SUV's with
snow plows - what prevents someone with a snow plow from getting a
cell phone?

6-ton? Me thinks you gotta get your head out of the poppy field
here son! You are really whacked!

--
Keith

default · Sep 29, 2004

On Sun, 21 Dec 2003 21:27:27 -0500, Keith R. Williams
<krw@attglobal.net> wrote:

In article <rg19uv84pr760u8g2ajcsu594q1p12f825@4ax.com>, R75/5
@defaulter.net says...
On Sat, 20 Dec 2003 11:51:33 -0500, Keith R. Williams
krw@attglobal.net> wrote:

In article <p3l8uvso6ophb0ba3cure4v2l7lg2alcjj@4ax.com>, R75/5
@defaulter.net says...
On Fri, 19 Dec 2003 21:44:04 GMT, Bob Stephens
stephensdigital@earthlink.net> wrote:

On Fri, 19 Dec 2003 12:22:22 -0800, Paul Hovnanian P.E. wrote:

Tarapia Tapioco wrote:

I want to build a mobile phone jammer

* short range (not more than 5 yds)
* handheld, small
* battery powered

so that when I'm on the bus/train and some idiot start loudly talking
about his business, I can press a button and cause just enough
interference to disconnect him mysteriously.

What's the problem? If someone annoys me too much with a phone, I just
offer to jam it somewhere. Manually. ;-)

When someone annoys me by yakking on a cell phone in a restaurant, meeting
etc., I just join right in the conversation "Sure thing Bill. Friday's
great. Just don't bring that whiny annoying wife of yours..." etc.
I get some priceless looks.

Bob
Hey that's pretty good - worth a try.

Now, what is your technique for getting the woman on the road in the
SUV who is ambivalent about which lane she intends to use?

Bigger SUV with snow blade on front.
Well that wouldn't work for long . . .

You have no clue how well it works. Mommy in the SUV will never
have a blade. Mommy in the SUV is petrified of anything larger
than she. A blade trumps a thousand pounds!

The whole idea of SUV's seems to be the "i'm bigger and badder don't
mess with me," syndrome. Whimps with a need to assert themselves?

Hogwash.
I think you're response just proved my point.

Doubtless that will draw a firestorm - but rationalize all you want -
you know, deep down, I'm right about this . . .

No, I know you're an idiot and a slimy leftist-pinko-drugged-up
freak! SUVs have this little 'U' in the middle.

So soon we are all trucking around in 6 ton, gas guzzling SUV's with
snow plows - what prevents someone with a snow plow from getting a
cell phone?

6-ton? Me thinks you gotta get your head out of the poppy field
here son! You are really whacked!

Damn pissed off another SUV owner . . . Why not just get some Viagra,
old man, and a more sensible vehicle? You'd save money and probably
have more fun. Assuming you can remember what fun is.

take care

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Keith R. Williams · Sep 29, 2004

In article <deqcuv4f4stf0uqirko8cnodfh37b4ditq@4ax.com>, R75/5
@defaulter.net says...

On Sun, 21 Dec 2003 21:27:27 -0500, Keith R. Williams
krw@attglobal.net> wrote:

In article <rg19uv84pr760u8g2ajcsu594q1p12f825@4ax.com>, R75/5
@defaulter.net says...
On Sat, 20 Dec 2003 11:51:33 -0500, Keith R. Williams
krw@attglobal.net> wrote:

In article <p3l8uvso6ophb0ba3cure4v2l7lg2alcjj@4ax.com>, R75/5
@defaulter.net says...
On Fri, 19 Dec 2003 21:44:04 GMT, Bob Stephens
stephensdigital@earthlink.net> wrote:

On Fri, 19 Dec 2003 12:22:22 -0800, Paul Hovnanian P.E. wrote:

Tarapia Tapioco wrote:

I want to build a mobile phone jammer

* short range (not more than 5 yds)
* handheld, small
* battery powered

so that when I'm on the bus/train and some idiot start loudly talking
about his business, I can press a button and cause just enough
interference to disconnect him mysteriously.

What's the problem? If someone annoys me too much with a phone, I just
offer to jam it somewhere. Manually. ;-)

When someone annoys me by yakking on a cell phone in a restaurant, meeting
etc., I just join right in the conversation "Sure thing Bill. Friday's
great. Just don't bring that whiny annoying wife of yours..." etc.
I get some priceless looks.

Bob
Hey that's pretty good - worth a try.

Now, what is your technique for getting the woman on the road in the
SUV who is ambivalent about which lane she intends to use?

Bigger SUV with snow blade on front.
Well that wouldn't work for long . . .

You have no clue how well it works. Mommy in the SUV will never
have a blade. Mommy in the SUV is petrified of anything larger
than she. A blade trumps a thousand pounds!

The whole idea of SUV's seems to be the "i'm bigger and badder don't
mess with me," syndrome. Whimps with a need to assert themselves?

Hogwash.
I think you're response just proved my point.

You're an idiot. ...any relationship to DimBulb? ...like his
sister, or sock-puppet? You're *that* close.

Doubtless that will draw a firestorm - but rationalize all you want -
you know, deep down, I'm right about this . . .

No, I know you're an idiot and a slimy leftist-pinko-drugged-up
freak! SUVs have this little 'U' in the middle.

So soon we are all trucking around in 6 ton, gas guzzling SUV's with
snow plows - what prevents someone with a snow plow from getting a
cell phone?

6-ton? Me thinks you gotta get your head out of the poppy field
here son! You are really whacked!

Damn pissed off another SUV owner . . .

Get your head out of the bong. 6-tons? You are an idiot! (a
12000lb SUV, man you gotta get with reality!) Drop your penis-
envy and get with reality!

....and no, I don't own an SUV of any kind. I do own a small 4WD
pickup. We've already had 5' of snow this year. 4WD has been
very useful!

Why not just get some Viagra,
old man, and a more sensible vehicle? You'd save money and probably
have more fun. Assuming you can remember what fun is.

Suck some more Ganja. You'll have loads of fun rotting your
brain further.

--
Keith

default · Sep 29, 2004

snip

Get your head out of the bong. 6-tons? You are an idiot! (a
12000lb SUV, man you gotta get with reality!) Drop your penis-
envy and get with reality!
Are you familiar with the concept of hyperbole? I intended that as

sarcasm, but didn't understand I was writing to the intellectually
challanged.

Bong? I thought that was a 60's thing. Do people still use those?

Never a cause for penis envy.

...and no, I don't own an SUV of any kind. I do own a small 4WD
pickup. We've already had 5' of snow this year. 4WD has been
very useful!
My PU is 10+ years old with 10,000 miles on it. I drive a relatively

small rusty beat up 20+ year old motorcycle or a bicycle.

Why not just get some Viagra,
old man, and a more sensible vehicle? You'd save money and probably
have more fun. Assuming you can remember what fun is.

Suck some more Ganja. You'll have loads of fun rotting your
brain further.
The only drugs I do are coffee and beer. I own a half-bottle of

aspirin - that's two years past its expiration date, does that count?

Maybe you should stop - I hear that ganja will affect sexual
performance. Ah . . . that's the reason for your vitriolic prose,
and reference to drugs?

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John Woodgate · Sep 29, 2004

I read in sci.electronics.design that default <R75/5@defaulter.net>
wrote (in <98vduv0m3i8ri5ulcq39pefe718kkp0vud@4ax.com&gt

about 'mobile
(cell) phone jamming', on Mon, 22 Dec 2003:

I own a half-bottle of
aspirin - that's two years past its expiration date, does that count?

Much of it will have decomposed. Open the bottle and sniff. If it smells
strongly of vinegar, throw them away.
--
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk
Interested in professional sound reinforcement and distribution? Then go to
http://www.isce.org.uk
PLEASE do NOT copy news posts to me by E-MAIL!

default · Sep 29, 2004

On Mon, 22 Dec 2003 16:03:45 +0000, John Woodgate
<jmw@jmwa.demon.contraspam.yuk> wrote:

I read in sci.electronics.design that default <R75/5@defaulter.net
wrote (in <98vduv0m3i8ri5ulcq39pefe718kkp0vud@4ax.com&gt about 'mobile
(cell) phone jamming', on Mon, 22 Dec 2003:

I own a half-bottle of
aspirin - that's two years past its expiration date, does that count?

Much of it will have decomposed. Open the bottle and sniff. If it smells
strongly of vinegar, throw them away.
Are you a chemist or pharmacist? Is it dangerous?

I thought the degradation byproduct are acetic and salicylic acid.
Acetic can't be that bad and salicylic - well that's wart remover so
might be, yet aspirin metabolizes in the body to salicylic acid.

Did find an interesting google on it . . .

Aspirin has been shown to cause a reduction in the virulence of Staphylococcus aureusâassociated
endocarditis. A new study reveals that salicylic acid, the major metabolite of aspirin, acts at the
level of transcription to downregulate the production of fibrinogen, fibronectin, and Îą-hemolysin â
virulence factors necessary for bacterial replication in host tissues and, now, potential therapeutic
targets.

So aspirin may help in preventing staphylococcal infections. Handy to
know if you're planning on a trip to the hospital.

Like they say: "Its not just for breakfast anymore."

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John Woodgate · Sep 29, 2004

I read in sci.electronics.design that default <R75/5@defaulter.net>
wrote (in <t2keuvgso79rqloi3opasqs9vk64qac0e3@4ax.com&gt

about 'mobile
(cell) phone jamming', on Mon, 22 Dec 2003:

On Mon, 22 Dec 2003 16:03:45 +0000, John Woodgate
jmw@jmwa.demon.contraspam.yuk> wrote:

I read in sci.electronics.design that default <R75/5@defaulter.net
wrote (in <98vduv0m3i8ri5ulcq39pefe718kkp0vud@4ax.com&gt about 'mobile
(cell) phone jamming', on Mon, 22 Dec 2003:

I own a half-bottle of
aspirin - that's two years past its expiration date, does that count?

Much of it will have decomposed. Open the bottle and sniff. If it smells
strongly of vinegar, throw them away.
Are you a chemist or pharmacist? Is it dangerous?

I studied chemistry for some years. Perhaps not dangerous, but
unpleasant to take because it's a lot more acidic, and aspirin is so
cheap that there seems no point in using outdated stuff.
--
Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk
Interested in professional sound reinforcement and distribution? Then go to
http://www.isce.org.uk
PLEASE do NOT copy news posts to me by E-MAIL!

Tarapia Tapioco · Sep 29, 2004

"Ken Taylor" <ken123@xtra.co.nz> wrote:

"Paul Burridge" <pb@osiris1.notthisbit.co.uk> wrote in message
news:5t1cuv4dn8bv354uodkbktss0gqo9rn1mb@4ax.com...
On 21 Dec 2003 13:11:20 -0000, nobody@See.Comments.Header (Italy
Anonymous Remailer) wrote:

Well, the OP did say he wanted a maximum range of 5 yds inside a bus.
Anyone know what sort of wattage that works out to? I suspect we're
talking about a few mW.

Or less, even. What power level do those car lock r/c key fob thingies
work at? That ought to give some sort of indication.

Why would it? The applications are totally different.

I agree. The car lock remote uses infrared (I think) and transmits a
very specific signal that the car receiver detects.

The jammer would use cellphone frequencies (around 9GHz and similar
bands, I think) and would need to transmit--I think--white noise
across the target band, strong enough to drown out the signal the
phone is already receiving.

Steve Terry · Sep 29, 2004

"Tarapia Tapioco" <comesefosse@ntani.firenze.linux.it> wrote in message
news:d72c4077f7a02194b9af258565c26b09@firenze.linux.it...

"Ken Taylor" <ken123@xtra.co.nz> wrote:
"Paul Burridge" <pb@osiris1.notthisbit.co.uk> wrote in message
news:5t1cuv4dn8bv354uodkbktss0gqo9rn1mb@4ax.com...
On 21 Dec 2003 13:11:20 -0000, nobody@See.Comments.Header (Italy
Anonymous Remailer) wrote:
snip
The jammer would use cellphone frequencies (around 9GHz and similar
bands, I think) and would need to transmit--I think--white noise
across the target band, strong enough to drown out the signal the
phone is already receiving.

You're making it up at you go along !

No, how you jam a GSM phone is use a UHF mixer oscillator with a 45MHz
Oscillator which is the difference between the RX and TX of a GSM phone,
and put in a delay line so that the output of the jammer is in phase with
the phones input, causing feedback that stops the phone working.

Allegedly similar mixer osc devices (without the need of a delay line)
have been used to jam amateur radio, police, and PMR repeaters.
So I've been told

Steve Terry

Ken Taylor · Sep 29, 2004

"Steve Terry" <g4wwk@despammed.com> wrote in message
news

X2Gb.9524$FN.8107@newsfep4-winn.server.ntli.net...

"Tarapia Tapioco" <comesefosse@ntani.firenze.linux.it> wrote in message
news:d72c4077f7a02194b9af258565c26b09@firenze.linux.it...
"Ken Taylor" <ken123@xtra.co.nz> wrote:
"Paul Burridge" <pb@osiris1.notthisbit.co.uk> wrote in message
news:5t1cuv4dn8bv354uodkbktss0gqo9rn1mb@4ax.com...
On 21 Dec 2003 13:11:20 -0000, nobody@See.Comments.Header (Italy
Anonymous Remailer) wrote:
snip
The jammer would use cellphone frequencies (around 9GHz and similar
bands, I think) and would need to transmit--I think--white noise
across the target band, strong enough to drown out the signal the
phone is already receiving.

You're making it up at you go along !

No, how you jam a GSM phone is use a UHF mixer oscillator with a 45MHz
Oscillator which is the difference between the RX and TX of a GSM phone,
and put in a delay line so that the output of the jammer is in phase with
the phones input, causing feedback that stops the phone working.

Allegedly similar mixer osc devices (without the need of a delay line)
have been used to jam amateur radio, police, and PMR repeaters.
So I've been told

Steve Terry

You'll have to run that one by me again - now I think *you're* making it up

as you go!

Ken

Steve Terry · Sep 29, 2004

"Ken Taylor" <ken123@xtra.co.nz> wrote in message
news:bsagk7$beutf$1@ID-76636.news.uni-berlin.de...

"Steve Terry" <g4wwk@despammed.com> wrote in message
newsX2Gb.9524$FN.8107@newsfep4-winn.server.ntli.net...
"Tarapia Tapioco" <comesefosse@ntani.firenze.linux.it> wrote in message
news:d72c4077f7a02194b9af258565c26b09@firenze.linux.it...
"Ken Taylor" <ken123@xtra.co.nz> wrote:
"Paul Burridge" <pb@osiris1.notthisbit.co.uk> wrote in message
news:5t1cuv4dn8bv354uodkbktss0gqo9rn1mb@4ax.com...
On 21 Dec 2003 13:11:20 -0000, nobody@See.Comments.Header (Italy
Anonymous Remailer) wrote:
snip
You'll have to run that one by me again - now I think *you're* making it up
as you go!
Ken

A GSM phone receives on around 950MHz and transmits 45MHz down on

around 905MHz with a difference in multiplexed time slots,
so if you can make a little receiver that takes the 905MHz signal from the phone
and mixes it with a 45MHz osc putting a signal back out into the phones
receiver,
and time delayed so it interferes with the same time slots in the phones
receiver
you'll get a howl round, or you won't, as the phone would lose the network
trying to do so

Steve Terry

Gordon Brown · Sep 29, 2004

"Steve Terry" <g4wwk@despammed.com> wrote in message
news:n64Gb.9605$FN.5109@newsfep4-winn.server.ntli.net...

A GSM phone receives on around 950MHz and transmits 45MHz down on
around 905MHz with a difference in multiplexed time slots,
so if you can make a little receiver that takes the 905MHz signal from the
phone
and mixes it with a 45MHz osc putting a signal back out into the phones
receiver,
and time delayed so it interferes with the same time slots in the phones
receiver
you'll get a howl round, or you won't, as the phone would lose the network
trying to do so

So how does the system know which frequency channel the mobile is on (there
could be several mobiles operating on several different channels
simultaneously) and how does this system cope with frequency hopping?

Steve Terry · Sep 29, 2004

"Gordon Brown" <.> wrote in message
news:3fe8d731$0$13354$cc9e4d1f@news-text.dial.pipex.com...

"Steve Terry" <g4wwk@despammed.com> wrote in message
news:n64Gb.9605$FN.5109@newsfep4-winn.server.ntli.net...
A GSM phone receives on around 950MHz and transmits 45MHz down on
around 905MHz with a difference in multiplexed time slots,
so if you can make a little receiver that takes the 905MHz signal from the
phone
and mixes it with a 45MHz osc putting a signal back out into the phones
receiver,
and time delayed so it interferes with the same time slots in the phones
receiver
you'll get a howl round, or you won't, as the phone would lose the network
trying to do so

So how does the system know which frequency channel the mobile is on (there
could be several mobiles operating on several different channels
simultaneously) and how does this system cope with frequency hopping?

You mix 45MHz with the phones own TX signal, from any phone nearby.

Then retransmitting itself up 45MHz into the phones receiver.

Whatever channel the phone is on, it's always a precise 45MHz diference

Without the phones transmit signal all the jammer puts out is it's 45MHz osc

What so difficult to understand ??

The difficult bit is adding the time delay so the phones TX time slots overlap
it's own RX time slots, otherwise the phone simply won't hear itself,
feedback, and stop working.

Steve Terry

Ken Taylor · Sep 29, 2004

"Steve Terry" <g4wwk@despammed.com> wrote in message
news:E55Gb.9655$FN.3222@newsfep4-winn.server.ntli.net...

"Gordon Brown" <.> wrote in message
news:3fe8d731$0$13354$cc9e4d1f@news-text.dial.pipex.com...
"Steve Terry" <g4wwk@despammed.com> wrote in message
news:n64Gb.9605$FN.5109@newsfep4-winn.server.ntli.net...
A GSM phone receives on around 950MHz and transmits 45MHz down on
around 905MHz with a difference in multiplexed time slots,
so if you can make a little receiver that takes the 905MHz signal from
the
phone
and mixes it with a 45MHz osc putting a signal back out into the
phones
receiver,
and time delayed so it interferes with the same time slots in the
phones
receiver
you'll get a howl round, or you won't, as the phone would lose the
network
trying to do so

So how does the system know which frequency channel the mobile is on
(there
could be several mobiles operating on several different channels
simultaneously) and how does this system cope with frequency hopping?

You mix 45MHz with the phones own TX signal, from any phone nearby.
Then retransmitting itself up 45MHz into the phones receiver.

Whatever channel the phone is on, it's always a precise 45MHz diference

Without the phones transmit signal all the jammer puts out is it's 45MHz
osc

What so difficult to understand ??

The difficult bit is adding the time delay so the phones TX time slots
overlap
it's own RX time slots, otherwise the phone simply won't hear itself,
feedback, and stop working.

Steve Terry

But they randomize time-slots within the TDMA. For just one problem with

this technique.

Ken

Gordon Brown · Sep 29, 2004

"Steve Terry" <g4wwk@despammed.com> wrote in message
news:E55Gb.9655$FN.3222@newsfep4-winn.server.ntli.net...

You mix 45MHz with the phones own TX signal, from any phone nearby.
Then retransmitting itself up 45MHz into the phones receiver.

Whatever channel the phone is on, it's always a precise 45MHz diference

Without the phones transmit signal all the jammer puts out is it's 45MHz
osc

What so difficult to understand ??

The difficult bit is adding the time delay so the phones TX time slots
overlap
it's own RX time slots, otherwise the phone simply won't hear itself,
feedback, and stop working.

Ah, I see, you mean a broadband jammer (otherwise it will not cope with two
phones transmitting on different channels). For some reason I was assuming
that it was some elaborate narrow band jamming device. Why not just transmit
a burst of white noise at 950Mhz with a 45MHz BW?

Thinker · Sep 29, 2004

"Tarapia Tapioco" <comesefosse@ntani.firenze.linux.it> wrote in message
news:d72c4077f7a02194b9af258565c26b09@firenze.linux.it...

"Ken Taylor" <ken123@xtra.co.nz> wrote:

"Paul Burridge" <pb@osiris1.notthisbit.co.uk> wrote in message
news:5t1cuv4dn8bv354uodkbktss0gqo9rn1mb@4ax.com...
On 21 Dec 2003 13:11:20 -0000, nobody@See.Comments.Header (Italy
Anonymous Remailer) wrote:

Well, the OP did say he wanted a maximum range of 5 yds inside a bus.
Anyone know what sort of wattage that works out to? I suspect we're
talking about a few mW.

Or less, even. What power level do those car lock r/c key fob thingies
work at? That ought to give some sort of indication.

Why would it? The applications are totally different.

I agree. The car lock remote uses infrared (I think)

If this is about North America you are way out to lunch. All we have here
are
RF remote controls for cars.

and transmits a

very specific signal that the car receiver detects.

The jammer would use cellphone frequencies (around 9GHz and similar
bands, I think) and would need to transmit--I think--white noise
across the target band, strong enough to drown out the signal the
phone is already receiving.

Steve Terry · Sep 29, 2004

"Gordon Brown" <.> wrote in message
news:3fe8ea32$0$9385$cc9e4d1f@news-text.dial.pipex.com...

"Steve Terry" <g4wwk@despammed.com> wrote in message
news:E55Gb.9655$FN.3222@newsfep4-winn.server.ntli.net...

You mix 45MHz with the phones own TX signal, from any phone nearby.
Then retransmitting itself up 45MHz into the phones receiver.

Whatever channel the phone is on, it's always a precise 45MHz diference

Without the phones transmit signal all the jammer puts out is it's 45MHz
osc

What so difficult to understand ??

The difficult bit is adding the time delay so the phones TX time slots
overlap
it's own RX time slots, otherwise the phone simply won't hear itself,
feedback, and stop working.

Ah, I see, you mean a broadband jammer (otherwise it will not cope with two
phones transmitting on different channels). For some reason I was assuming
that it was some elaborate narrow band jamming device. Why not just transmit
a burst of white noise at 950Mhz with a 45MHz BW?

Broadband yes, but not broadband jamming, it's providing from the phone TX

a mixed signal to go back into a phones RX, the more phones within it's range
it's trying to mix, the weaker the individual output signal from it.

Steve Terry

Steve Terry · Sep 29, 2004

"Ken Taylor" <ken123@xtra.co.nz> wrote in message
news:bsapc3$asvjt$1@ID-76636.news.uni-berlin.de...

"Steve Terry" <g4wwk@despammed.com> wrote in message
news:E55Gb.9655$FN.3222@newsfep4-winn.server.ntli.net...

"Gordon Brown" <.> wrote in message
news:3fe8d731$0$13354$cc9e4d1f@news-text.dial.pipex.com...
"Steve Terry" <g4wwk@despammed.com> wrote in message
news:n64Gb.9605$FN.5109@newsfep4-winn.server.ntli.net...
snip
The difficult bit is adding the time delay so the phones TX time slots
overlap
it's own RX time slots, otherwise the phone simply won't hear itself,
feedback, and stop working.
Steve Terry

But they randomize time-slots within the TDMA. For just one problem with
this technique.
Ken

Doesn't have to be precise, just as so there's enough time slots interfered

with to stop the phone from working.

Steve Terry

Jim Thompson · Sep 29, 2004

On Tue, 23 Dec 2003 20:10:37 +0100 (CET), Tarapia Tapioco
<comesefosse@ntani.firenze.linux.it> wrote:

[snip]

.... The car lock remote uses infrared (I think) and transmits a
very specific signal that the car receiver detects.

The jammer would use cellphone frequencies (around 9GHz and similar
bands, I think) and would need to transmit--I think--white noise
across the target band, strong enough to drown out the signal the
phone is already receiving.

ROTFLMAO! Infrared ?

9GHz ?

480)460-2350 | |
| E-mail Address at Website Fax

Frank Bemelman · Sep 29, 2004

"Fred Bloggs" <nospam@nospam.com> schreef in bericht
news:3FF0A1C6.4050404@nospam.com...

[snip]

Then you can work a common 5.1V zener into the equation like so:
Use a 2N3906 for the pnp for Vbe,max=6V rating.

Please view in a fixed-width font such as Courier.

6V >---+--------+----------+-------------+
| | | |
| / / |
| 22 51 |
| / / |
| \ \ c
| | | |/
| +----------|-----------| TIP31
| | | |\
| | | e----+--> 5V
| c | |
| \| | pnp |
| npn |--+-----|-------- c e---+
| /| | | \ / |
| e | | ---- |
=== | | | 180 | |
| | | +----/\/\---+ |
| | | | | |
| | | | | |
| | / _/ / ===
| | 1K /^ 5.1v 1.2K 1000U
| | / - / |
| | \ | \ |
| | | | | |
GND>--+--------+----+-----+-----------+------+--> GND

Now you're getting a bit too enthusiastic ;-) With all
these parts, I'd prefer a LM2931 for 27 cents.

http://www.national.com/pf/LM/LM2931.html

--
Thanks, Frank.
(remove 'x' and 'invalid' when replying by email)

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