🚀 go-pugleaf

Adam <hideo@tne.net.au> wrote in message news:3b04d952.4676022@news.tne.net.au...

> Most of us have seen the warning signs at petrol stations
> telling us to switch off our mobile phones. Obviously, some
> people believe that the transmission from a mobile phone
> is powerful enough to induce a spark in a nearby object.

It is theoretically possible. And it doesnt need to be 'powerful enough'

> What about sensitive electronic componentry thats
> particularly susceptible to electrostatic discharge?

Again, its theoretically possible.

> If a mobile phone is operated near such
> equipment/components, is there a risk of damage?

Not due to 'electrostatic discharge'

> Can the signal couple with a loop on a PCB and induce
> a voltage capable of destroying a sensitive device?

In theory, yes. In practice stuff is normally designed so that
doesnt happen, just so it doesnt get fried by lots of other stuff.

> eg. If you're modifiying your computer & receive
> a call on our mobile, is it actually possible to screw
> up your motherboard if you get too close to it?

Nope.

> I've spoken to an Electrical Engineer about this,
> and we were unable to discount the possibility.

Its not impossible, but I doubt anyone has seen it happen.

> If anyone knows more, please contribute.

Forget about the worry about mobile phones, what about faulty spark plug
leads and gas appliances like caravan refrigerators.  It think it is
hilarious the mobile phone signs.  I do not know anyone that switches their
phone off.  I have an in car phone and a CDMA in my pocket and would never
switch them off.  As I am often on call for emergencies my CDMA phone is
grafted to my right hand and never switched off.

--
Whatever you wish for me,
May you have twice as much.

"Adam" <hideo@tne.net.au> wrote in message
news:3b04d952.4676022@news.tne.net.au...
> Most of us have seen the warning signs at petrol stations telling us
> to switch off our mobile phones. Obviously, some people believe that
> the transmission from a mobile phone is powerful enough to induce a
> spark in a nearby object.
>
> What about sensitive electronic componentry thats particularly
> susceptible to electrostatic discharge? If a mobile phone is operated
> near such equipment/components, is there a risk of damage? Can the
> signal couple with a loop on a PCB and induce a voltage capable of
> destroying a sensitive device? eg. If you're modifiying your computer
> & receive a call on your mobile, is it actually possible to screw up
> your motherboard if you get too close to it?
>
> I've spoken to an Electrical Engineer about this, and we were unable
> to discount the possibility. If anyone knows more, please contribute.
>
> Thanks,
> Adam Gerlach.

Adam wrote:

> What about sensitive electronic componentry thats particularly
> susceptible to electrostatic discharge? If a mobile phone is operated
> near such equipment/components, is there a risk of damage? Can the
> signal couple with a loop on a PCB and induce a voltage capable of
> destroying a sensitive device? eg. If you're modifiying your computer
> & receive a call on your mobile, is it actually possible to screw up
> your motherboard if you get too close to it?

I personally saw a piece of digital scientific gear
become permanently damaged when a high power walkie
talkie was keyed on about three feet front the gear.


-- 
If you are one in a million; there are 6000 people just like
you.



Opinions expressed herein are my own and may not represent those of my employer.

On Fri, 18 May 2001 08:14:42 GMT, hideo@tne.net.au (Adam) wrote, after pausing
and ensuring that what they were going to write was not absolute gobbledy-gook:

>Most of us have seen the warning signs at petrol stations telling us
>to switch off our mobile phones. Obviously, some people believe that
>the transmission from a mobile phone is powerful enough to induce a
>spark in a nearby object.

Not quite.  A case that comes to mind is where, in jostling the phone at your
ear and hands, the battery pack momentarily loses contact and sparks.  This is
more than concern, rather than EMF related combustion from heating.  But there
is equally as much threat from dodgy wiring in the car, fuel dropping on hot
exhaust etc.  Hence the other reason you should turn your car off while filling
it.

>What about sensitive electronic componentry thats particularly
>susceptible to electrostatic discharge? If a mobile phone is operated
>near such equipment/components, is there a risk of damage? Can the
>signal couple with a loop on a PCB and induce a voltage capable of
>destroying a sensitive device? eg. If you're modifiying your computer
>& receive a call on your mobile, is it actually possible to screw up
>your motherboard if you get too close to it?
>
>I've spoken to an Electrical Engineer about this, and we were unable
>to discount the possibility. If anyone knows more, please contribute.

Theoretically, its possible I suppose, due to induced current (voltage), you'd
have to have all the conditions right though, not merely just the presence of a
circuit and an operating mobile phone (eg you'd need a circuit with something to
act as the 'aerial' in it etc etc etc ...).

Dion M.
http://dionsplace.terrashare.com/

"It takes a lot of brains to enjoy satire, humour and wit - but none to be offended by them."

On Fri, 18 May 2001 08:14:42 GMT, hideo@tne.net.au (Adam) wrote:

>Most of us have seen the warning signs at petrol stations telling us
>to switch off our mobile phones. Obviously, some people believe that
>the transmission from a mobile phone is powerful enough to induce a
>spark in a nearby object.

It is not because of the risk of *inducing* a spark, but actually
*creating* one. I may be wrong, but I was told many years ago this
reason for the warning, and it sounds more plausable to me:

It may be outdated now - but early mobile phones used to have a
powerpack on the back that could easily come off.  If that happens
while you are using it (and thus drawing current), the disconnection
will cause a spark.

Just my 2c, hope that cross-answering is forgiven...

         Bart.

There may be a 'NOSPAM.' in front of my E-mail address.
It is there to fool machines, not people. 
Please remove it when you reply.

Then again, it could be because your phone causes you not to pay attention
to the audio "commercials" that many stations play while you're fueling.

Adam <hideo@tne.net.au> wrote in message
news:3b04d952.4676022@news.tne.net.au...
> Most of us have seen the warning signs at petrol stations telling us
> to switch off our mobile phones. Obviously, some people believe that
> the transmission from a mobile phone is powerful enough to induce a
> spark in a nearby object.
>
> What about sensitive electronic componentry thats particularly
> susceptible to electrostatic discharge? If a mobile phone is operated
> near such equipment/components, is there a risk of damage? Can the
> signal couple with a loop on a PCB and induce a voltage capable of
> destroying a sensitive device? eg. If you're modifiying your computer
> & receive a call on your mobile, is it actually possible to screw up
> your motherboard if you get too close to it?
>
> I've spoken to an Electrical Engineer about this, and we were unable
> to discount the possibility. If anyone knows more, please contribute.
>
> Thanks,
> Adam Gerlach.
The reason given to me buy a friend who owned a petrol station was that the
people using a mobile phone would be busy on the phone and not look where
they were going, and step into on coming cars, if they swerved to miss the
person they could hit a petrol pump and cause damage that way.

Regards,

Kat.

When I was doing my engineering degree, I was told the danger from mobile
phones came from the electronic equipment picking up the RF (radio
frequency) signals from the phone.

Basically, a mobile phone minimises the amount of RF as much as possible.
However, if you walk into a low reception area, it can boost the power of
it's RF to greater levels to try and keep a good connection the base
station.

Now in electronic equipment, there are often small wires sticking up or
short wire traces on the motherboard. When the mobile phone boosts it's RF
power, these small wire stubs act as small atennae. The RF signal is picked
up and transmitted along the electronic equipments circuit where it may end
up 'entering' an electronic component. Electronic components, especially IC
chips are designed to accept voltages/currents within certain tolerances. If
they receive voltages/current outside these tolerances, that's when they can
be damaged.

Hence, the unexpected RF signal that comes down the circuit can damage the
electronic component.

What I have just said is something I read in an electronics magazine once -
but I can't remember where or when.

Roy McCammon wrote:
> 
> Adam wrote:
> 
> > What about sensitive electronic componentry thats particularly
> > susceptible to electrostatic discharge? If a mobile phone is operated
> > near such equipment/components, is there a risk of damage? Can the
> > signal couple with a loop on a PCB and induce a voltage capable of
> > destroying a sensitive device? eg. If you're modifiying your computer
> > & receive a call on your mobile, is it actually possible to screw up
> > your motherboard if you get too close to it?
> 
> I personally saw a piece of digital scientific gear
> become permanently damaged when a high power walkie
> talkie was keyed on about three feet front the gear.

Wow. That must have been a -very- powerful walkie talkie. Aren't most
cell phones transmitting only a few hundred milliwatts?

I can't help but think that this digital scientific gear was badly
designed.

Steve Greenfield

Steve Greenfield wrote:

> > I personally saw a piece of digital scientific gear
> > become permanently damaged when a high power walkie
> > talkie was keyed on about three feet front the gear.
> 
> Wow. That must have been a -very- powerful walkie talkie. Aren't most
> cell phones transmitting only a few hundred milliwatts?

They were military walkie-talkies.  I'd guess in the 10Watt
range.

> I can't help but think that this digital scientific gear was badly
> designed.

Don't know.  It did have long coax cables connected to it.
It was a time code generator for use with a big Ampex multi
channel recorder.  It also radiated significantly.


-- 
If you are one in a million; there are 6000 people just like
you.



Opinions expressed herein are my own and may not represent those of my employer.

Me wrote:
> 
> When I was doing my engineering degree, I was told the danger from mobile
> phones came from the electronic equipment picking up the RF (radio
> frequency) signals from the phone.
> 
> Basically, a mobile phone minimises the amount of RF as much as possible.
> However, if you walk into a low reception area, it can boost the power of
> it's RF to greater levels to try and keep a good connection the base
> station.
> 
> Now in electronic equipment, there are often small wires sticking up or
> short wire traces on the motherboard. When the mobile phone boosts it's RF
> power, these small wire stubs act as small atennae. The RF signal is picked
> up and transmitted along the electronic equipments circuit where it may end
> up 'entering' an electronic component. Electronic components, especially IC
> chips are designed to accept voltages/currents within certain tolerances. If
> they receive voltages/current outside these tolerances, that's when they can
> be damaged.
> 
> Hence, the unexpected RF signal that comes down the circuit can damage the
> electronic component.

If you manage to build a resonant structure and hit it with 
the right RF, you can get lots of volts.  As cell phone
freqs go up and wave lengths get smaller there is more
chance of that happening.

-- 
If you are one in a million; there are 6000 people just like
you.



Opinions expressed herein are my own and may not represent those of my employer.

In sci.electronics.components Steve Greenfield <polymorph@polyphoto.com> wrote:

> Wow. That must have been a -very- powerful walkie talkie. Aren't most
> cell phones transmitting only a few hundred milliwatts?

Several watts for the more powerful ones. 

> I can't help but think that this digital scientific gear was badly
> designed.

Possibly, though I can imagine some kinds of equipment that would, 
by its nature, be difficult to protect against strong RF fields. 

Bestr regards, 
-- 
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Spehro Pefhany --"it's the network..."            "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com
Contributions invited->The AVR-gcc FAQ is at: http://www.BlueCollarLinux.com
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

On Fri, 18 May 2001 15:49:24 GMT, "Me" <tobtoh@hotmail.com> wrote:

>When I was doing my engineering degree, I was told the danger from mobile
>phones came from the electronic equipment picking up the RF (radio
>frequency) signals from the phone.
>
>Basically, a mobile phone minimises the amount of RF as much as possible.
>However, if you walk into a low reception area, it can boost the power of
>it's RF to greater levels to try and keep a good connection the base
>station.
>
>Now in electronic equipment, there are often small wires sticking up or
>short wire traces on the motherboard. When the mobile phone boosts it's RF
>power, these small wire stubs act as small atennae. The RF signal is picked
>up and transmitted along the electronic equipments circuit where it may end
>up 'entering' an electronic component. Electronic components, especially IC
>chips are designed to accept voltages/currents within certain tolerances. If
>they receive voltages/current outside these tolerances, that's when they can
>be damaged.
>
>Hence, the unexpected RF signal that comes down the circuit can damage the
>electronic component.
>
>What I have just said is something I read in an electronics magazine once -
>but I can't remember where or when.
>

As a practical matter, a cell phone emits puny amounts of power. While
you *might* temporarily disrupt the operation of a poorly-shielded
device (semiconductor junctions could rectify the RF and make DC
offsets in the millivolt range)  a cell phone doesn't have anything
like the energy density to kill a semiconductor. There are lots of far
more powerful RF sources around - ham radio, airport radars, AM/FM/TV
transmitters-  and they don't zap things.

John

reichln@navix.net (Gary Reichlinger) wrote:

]On Fri, 18 May 2001 08:14:42 GMT, hideo@tne.net.au (Adam) wrote:
]
]>I've spoken to an Electrical Engineer about this, and we were unable
]>to discount the possibility. If anyone knows more, please contribute.
]	The electric field created by a power line would be much
]stronger than that created by a mobile phone.  Also, the lower
]frequency put out by power lines is more difficult to shield against
]than cell phone frequencies.  Therefore, if your cell phone could
]damage your circuit, you should only use it in areas that do not have
]power lines or electrical equipment (the Outback?).

Ha Ha Ha.

I'd just like to clear somthing up here: Outback Australia has got lots
of power lines, internet access, electricity, sealed roads, bridges, etc.

It does not have mobile phone coverage. 

If you are leaving the coast, there are very few areas that have mobie
coverage. Don't rely on it for anything, esp safety.

But with a CB radio, u can often be heard 100% on their PA system here at
the  local ice cream parlor. The CB radiated signal overload their music
easely.
����������������������������������������������������������������������������
�����������
"David VanHorn" <dvanhorn@cedar.net> wrote in message
news:p8aN6.6916$Ji.151091@news1.rdc1.il.home.com...
> Then again, it could be because your phone causes you not to pay attention
> to the audio "commercials" that many stations play while you're fueling.
>
>
>
>
>

How come they dont ask us to ground our car body when fueling ????  The big
cistern delivery truck have to gnd themselve very well before filling their
cistern ???

======================================
"Wayne" <whalcomb@lucent.com> wrote in message
news:9e3r2u$snq@nntpb.cb.lucent.com...
> From now on I will stop my car 100 ft from the pumps and push it the rest
of
> the way.   And I will wear an ESD wrist strap grounded to the pump and
> another strap connecting the car chassis to the pump before starting to
add
> the fuel.
>
>
> "Adam" <hideo@tne.net.au> wrote in message
> news:3b04d952.4676022@news.tne.net.au...
> > Most of us have seen the warning signs at petrol stations telling us
> > to switch off our mobile phones. Obviously, some people believe that
> > the transmission from a mobile phone is powerful enough to induce a
> > spark in a nearby object.
> >
> > What about sensitive electronic componentry thats particularly
> > susceptible to electrostatic discharge? If a mobile phone is operated
> > near such equipment/components, is there a risk of damage? Can the
> > signal couple with a loop on a PCB and induce a voltage capable of
> > destroying a sensitive device? eg. If you're modifiying your computer
> > & receive a call on your mobile, is it actually possible to screw up
> > your motherboard if you get too close to it?
> >
> > I've spoken to an Electrical Engineer about this, and we were unable
> > to discount the possibility. If anyone knows more, please contribute.
> >
> > Thanks,
> > Adam Gerlach.
>
>
>

Whats a keyfobs ????

======================================
"DB" <mailus@ourwebsite.com> wrote in message
news:2o3bgtg247hn8drt7fr49ehoe4o1dijjv0@4ax.com...
> On Fri, 18 May 2001 13:58:19 -0500, "Wayne" <whalcomb@lucent.com>
> wrote:
>
> >Then by the same reason they need to ban keyfobs.
> >
>
> Dont tell them they probably would.
> They are not an electronics industry they are
> the Petroleum industry.
>
>

George Dau <gedau@isa.mapson.com.au> wrote in
message news:3b05b8b9.1547262065@172.22.22.15...
> reichln@navix.net (Gary Reichlinger) wrote:
>
> ]On Fri, 18 May 2001 08:14:42 GMT, hideo@tne.net.au (Adam) wrote:
> ]
> ]>I've spoken to an Electrical Engineer about this, and we were unable
> ]>to discount the possibility. If anyone knows more, please contribute.
> ] The electric field created by a power line would be much
> ]stronger than that created by a mobile phone.  Also, the lower
> ]frequency put out by power lines is more difficult to shield against
> ]than cell phone frequencies.  Therefore, if your cell phone could
> ]damage your circuit, you should only use it in areas that do not have
> ]power lines or electrical equipment (the Outback?).

> Ha Ha Ha.

> I'd just like to clear somthing up here:

You didnt. Mangled it yourself.

> Outback Australia has got lots of power lines, internet
> access, electricity, sealed roads, bridges, etc.

Yes, tho 'lots of power lines' is overstating it.

> It does not have mobile phone coverage.

Bullshit.

> If you are leaving the coast, there are very
> few areas that have mobie coverage.

Complete and utter bullshit. Have a look at the coverage maps some time.

> Don't rely on it for anything, esp safety.

Depends on what sort of mobile phone it is. Satellite phones are fine.

gudule <gudule88@sympatico.ca> wrote in message
news:kTjN6.22645$ee1.1633287@news20.bellglobal.com...

> How come they dont ask us to ground our car body when fueling ????

Coz its a trivial risk.

> The big cistern delivery truck have to gnd themselve
> very well before filling their cistern ???

They're called tankers here. It isnt really necessary, just a precaution.

> ======================================
> "Wayne" <whalcomb@lucent.com> wrote in message
> news:9e3r2u$snq@nntpb.cb.lucent.com...
> > From now on I will stop my car 100 ft from the pumps and push it the rest
> of
> > the way.   And I will wear an ESD wrist strap grounded to the pump and
> > another strap connecting the car chassis to the pump before starting to
> add
> > the fuel.
> >
> >
> > "Adam" <hideo@tne.net.au> wrote in message
> > news:3b04d952.4676022@news.tne.net.au...
> > > Most of us have seen the warning signs at petrol stations telling us
> > > to switch off our mobile phones. Obviously, some people believe that
> > > the transmission from a mobile phone is powerful enough to induce a
> > > spark in a nearby object.
> > >
> > > What about sensitive electronic componentry thats particularly
> > > susceptible to electrostatic discharge? If a mobile phone is operated
> > > near such equipment/components, is there a risk of damage? Can the
> > > signal couple with a loop on a PCB and induce a voltage capable of
> > > destroying a sensitive device? eg. If you're modifiying your computer
> > > & receive a call on your mobile, is it actually possible to screw up
> > > your motherboard if you get too close to it?
> > >
> > > I've spoken to an Electrical Engineer about this, and we were unable
> > > to discount the possibility. If anyone knows more, please contribute.
> > >
> > > Thanks,
> > > Adam Gerlach.
> >
> >
> >
>
>

"Rod Speed" <rod_speed@yahoo.com> wrote:

]George Dau <gedau@isa.mapson.com.au> wrote in

]> If you are leaving the coast, there are very
]> few areas that have mobie coverage.
]
]Complete and utter bullshit. Have a look at the coverage maps some time.
]
]> Don't rely on it for anything, esp safety.
]
]Depends on what sort of mobile phone it is. Satellite phones are fine.

Sat phones are different. I was talking normal mobiles. I went and found some
coverage maps, and they match what I said. You must have different maps.

Queensland:
http://www.telstra.com.au/mobilenet/network/dgqldmp.htm
Clearly only the coast, South West Qld, and a few isolated places inland.

Nothern Territory:
http://www.telstra.com.au/mobilenet/network/dgntmp.htm
Very little coverage.

Western Australia:
http://www.telstra.com.au/mobilenet/network/dgscwamp.htm
South isn't too bad, but the North hasn't got much.

There is coverage in major centres, but if you are on the road, you wont get
much coverage. I've met tourists who had intended to rely on their mobiles when
travelling, and they were caught out when they found out that mobiles do not
work in most areas.

Rod, have you got some coverage maps that show a different picture? Post the
URLs - I am genuinely interested.


-- 
Sadly, I've had to munge my e-mail address to reduce
spam. Reply to the newsgroup.

On Sat, 19 May 2001 00:10:46 GMT, gedau@isa.mapson.com.au (George Dau)
wrote:

>
>I'd just like to clear somthing up here: Outback Australia has got lots
>of power lines, internet access, electricity, sealed roads, bridges, etc.
>
	Sorry, I did not mean to disparage your country.  I could not
resist the suggestion due to the thread originator's ".au" email
address.

On Fri, 18 May 2001 16:09:14 GMT, Steve Greenfield
<polymorph@polyphoto.com> put finger to keyboard and composed:

>Roy McCammon wrote:
>> 
>> Adam wrote:
>> 
>> > What about sensitive electronic componentry thats particularly
>> > susceptible to electrostatic discharge? If a mobile phone is operated
>> > near such equipment/components, is there a risk of damage? Can the
>> > signal couple with a loop on a PCB and induce a voltage capable of
>> > destroying a sensitive device? eg. If you're modifiying your computer
>> > & receive a call on your mobile, is it actually possible to screw up
>> > your motherboard if you get too close to it?
>> 
>> I personally saw a piece of digital scientific gear
>> become permanently damaged when a high power walkie
>> talkie was keyed on about three feet front the gear.
>
>Wow. That must have been a -very- powerful walkie talkie. Aren't most
>cell phones transmitting only a few hundred milliwatts?
>
>I can't help but think that this digital scientific gear was badly
>designed.

I once heard my neighbour's CB radio conversation on my Yamaha organ's
speaker. The organ was powered off.


-- Franc Zabkar

Please remove one 'g' from my address when replying by email.

George Dau <gedau@isa.mapson.com.au> wrote in
message news:3b05f297.5787041@172.22.22.15...
> Rod Speed <rod_speed@yahoo.com> wrote
>> George Dau <gedau@isa.mapson.com.au> wrote

>>> If you are leaving the coast, there are very
>>> few areas that have mobie coverage.

>> Complete and utter bullshit. Have a look at the coverage maps some time.

>>> Don't rely on it for anything, esp safety.

>> Depends on what sort of mobile phone it is. Satellite phones are fine.

> Sat phones are different. I was talking normal mobiles.

Sure, that was just a comment on your 'Don't rely on it for anything, esp safety'

> I went and found some coverage maps, and they match what I said.

Bullshit they do.

> You must have different maps.

Or you aint gotta clue about even the simplest stuff on
that completely stupid 'If you are leaving the coast, there
are very few areas that have mobie coverage' claim.

> Queensland:
> http://www.telstra.com.au/mobilenet/network/dgqldmp.htm

Wrong map, you should be using
http://www.telstra.com.au/mobilenet/network/cdma_bro/cdma_qld.htm

> Clearly only the coast, South West Qld, and a few isolated places inland.

Wrong with the CDMA coverage you should be using.

> Nothern Territory:
> http://www.telstra.com.au/mobilenet/network/dgntmp.htm

Wrong map again, try
http://www.telstra.com.au/mobilenet/network/cdma_bro/cdma_nt.htm

> Very little coverage.

Wrong again. Lots of coverage, every significant town and quite
a way outside them. Nothing like your silly claim about just the coast.

> Western Australia:
> http://www.telstra.com.au/mobilenet/network/dgscwamp.htm

Wrong map again, try
http://www.telstra.com.au/mobilenet/network/cdma_bro/cdma_wa.htm

> South isn't too bad,

Nothing like your silly claim about just the coast.

> but the North hasn't got much.

More bullshit.

> There is coverage in major centres, but if you
> are on the road, you wont get much coverage.

Bullshit. There is very decent coverage on the major inland highways. While
not gap free, its nothing like your completely silly claim about just the coast.

And there is the tiny matter of
http://www.telstra.com.au/mobilenet/network/cdma_bro/cdma_nsw.htm
which shows nothing like your completely silly claim about just the coast.

> I've met tourists who had intended to rely on their
> mobiles when travelling, and they were caught out when
> they found out that mobiles do not work in most areas.

Presumably stupids who dont realise that they need CDMA.
That 'do not work in most areas' is just plain wrong.

And there's also the tiny matter of the Vodafone GlobalStar service.

> Rod, have you got some coverage maps that show a different picture?

Yep.

> Post the URLs - I am genuinely interested.

You looked at the wrong maps.

They're probably mostly worried about the cell phone upsetting the petrol
pump controller causing it issue more petrol than it's charging you for.

Aeroplanes are more of a worry. Is it sensible to fly at that altitude and
speed in a machine that can be disabled or loose its way because of a nearby
cell phone or lap-top computer.

--
Regards
Paul Bealing
PMB Electronics
www.pmb.co.nz


"Adam" <hideo@tne.net.au> wrote in message
news:3b04d952.4676022@news.tne.net.au...
> Most of us have seen the warning signs at petrol stations telling us
> to switch off our mobile phones. Obviously, some people believe that
> the transmission from a mobile phone is powerful enough to induce a
> spark in a nearby object.
>
> What about sensitive electronic componentry thats particularly
> susceptible to electrostatic discharge? If a mobile phone is operated
> near such equipment/components, is there a risk of damage? Can the
> signal couple with a loop on a PCB and induce a voltage capable of
> destroying a sensitive device? eg. If you're modifiying your computer
> & receive a call on your mobile, is it actually possible to screw up
> your motherboard if you get too close to it?
>
> I've spoken to an Electrical Engineer about this, and we were unable
> to discount the possibility. If anyone knows more, please contribute.
>
> Thanks,
> Adam Gerlach.

On Fri, 18 May 2001 17:04:00 GMT, reichln@navix.net (Gary Reichlinger)
wrote:

>	The electric field created by a power line would be much
>stronger than that created by a mobile phone.  Also, the lower
>frequency put out by power lines is more difficult to shield against
>than cell phone frequencies.  Therefore, if your cell phone could
>damage your circuit, you should only use it in areas that do not have
>power lines or electrical equipment (the Outback?).

Maybe I should take a long 1/2hr drive to the "outback" ;-))

But seriously, I'm no RF expert, but I believe fields at such low
(50/60Hz) frequencies must be much stronger than RF to have the same
influence on a sensitive circuit.

Having said that, I guess it also depends on the circuit being
inadvertently tuned & therefore may only be adversely affected by one
or more bands of interfering frequencies...

-Adam Gerlach.

On Sat, 19 May 2001 18:33:25 +1200, "Paul Bealing" <paul@pmb.co.nz>
wrote:

>They're probably mostly worried about the cell phone upsetting the petrol
>pump controller causing it issue more petrol than it's charging you for.

Ha ha... now that makes sense :-)

How many times has a vending machine failed & gave you a free Coke?
How many times has it failed & stolen your money?

0/13?

>
>Aeroplanes are more of a worry. Is it sensible to fly at that altitude and
>speed in a machine that can be disabled or loose its way because of a nearby
>cell phone or lap-top computer.

Actually, I was speaking of electronics outside of their "normal
operating enclosures" eg. bare PC mobo's, peripheral cards & such. I
would think Aircraft electronics would be well protected in flight,
and possibly pre-tested against a wide spectrum of interference.

>
>--
>Regards
>Paul Bealing
>PMB Electronics
>www.pmb.co.nz

Paul Bealing <paul@pmb.co.nz> wrote in message news:9e53rc$1kvc$1@raewyn.paradise.net.nz...

> They're probably mostly worried about the cell phone upsetting the petrol
> pump controller causing it issue more petrol than it's charging you for.

Nope.

> Aeroplanes are more of a worry.

Nope.

> Is it sensible to fly at that altitude and speed in a machine that can be
> disabled or loose its way because of a nearby cell phone or lap-top computer.

Fantasy.


> "Adam" <hideo@tne.net.au> wrote in message
> news:3b04d952.4676022@news.tne.net.au...
> > Most of us have seen the warning signs at petrol stations telling us
> > to switch off our mobile phones. Obviously, some people believe that
> > the transmission from a mobile phone is powerful enough to induce a
> > spark in a nearby object.
> >
> > What about sensitive electronic componentry thats particularly
> > susceptible to electrostatic discharge? If a mobile phone is operated
> > near such equipment/components, is there a risk of damage? Can the
> > signal couple with a loop on a PCB and induce a voltage capable of
> > destroying a sensitive device? eg. If you're modifiying your computer
> > & receive a call on your mobile, is it actually possible to screw up
> > your motherboard if you get too close to it?
> >
> > I've spoken to an Electrical Engineer about this, and we were unable
> > to discount the possibility. If anyone knows more, please contribute.
> >
> > Thanks,
> > Adam Gerlach.
>
>

Whilst licking their paws onSat, 19 May 2001 07:20:58 GMT,
hideo@tne.net.au (Adam) purred:

>On Sat, 19 May 2001 18:33:25 +1200, "Paul Bealing" <paul@pmb.co.nz>
>wrote:
>
>>They're probably mostly worried about the cell phone upsetting the petrol
>>pump controller causing it issue more petrol than it's charging you for.
>
>Ha ha... now that makes sense :-)
>
>How many times has a vending machine failed & gave you a free Coke?
>How many times has it failed & stolen your money?

There was a machine at my school that if you put in 1 dollar 40 cents
in 10 cent coins it gave you a free drink and 10 dollars.
>
>0/13?
>
>>
>>Aeroplanes are more of a worry. Is it sensible to fly at that altitude and
>>speed in a machine that can be disabled or loose its way because of a nearby
>>cell phone or lap-top computer.
>
>Actually, I was speaking of electronics outside of their "normal
>operating enclosures" eg. bare PC mobo's, peripheral cards & such. I
>would think Aircraft electronics would be well protected in flight,
>and possibly pre-tested against a wide spectrum of interference.
>
>>
>>--
>>Regards
>>Paul Bealing
>>PMB Electronics
>>www.pmb.co.nz


          ____
        /  @   \==]|[=(]
       |--------|
       ==========       .  *                                     
       ==========     .\ * . *.   *                         
      ||||||||||||      \ * ./  *    .   *    
     |||||||||| --]%%%%%% .- =--=---=-=-=-=-=
     [=========\  ]===========(  *                           
    [==============|   / *  \    .                          
    C| @ @ @ @ @ @ D         *      *                        
     |              \           .                          
   C| @  @ @  @ @ @  D       .
    |                 \          *                         
  C| @  @  @  @  @  @  D
   |                    \
 C| @  @  @   @   @   @  D
  |                       \
 |@@@@@@@@@@@@@@@@@@@@@@@@@|
  -------------------------

On Fri, 18 May 2001 21:21:34 -0400, "gudule" <gudule88@sympatico.ca>
wrote:

>How come they dont ask us to ground our car body when fueling ????  The big
>cistern delivery truck have to gnd themselve very well before filling their
>cistern ???

Well...there is a danger of gas being ignited when filling a gas can
in the back of a pickup truck with a box liner...I saw a warning
posted against that about 4 or 5 years ago.

Tom

>
>======================================
>"Wayne" <whalcomb@lucent.com> wrote in message
>news:9e3r2u$snq@nntpb.cb.lucent.com...
>> From now on I will stop my car 100 ft from the pumps and push it the rest
>of
>> the way.   And I will wear an ESD wrist strap grounded to the pump and
>> another strap connecting the car chassis to the pump before starting to
>add
>> the fuel.
>>
>>
>> "Adam" <hideo@tne.net.au> wrote in message
>> news:3b04d952.4676022@news.tne.net.au...
>> > Most of us have seen the warning signs at petrol stations telling us
>> > to switch off our mobile phones. Obviously, some people believe that
>> > the transmission from a mobile phone is powerful enough to induce a
>> > spark in a nearby object.
>> >
>> > What about sensitive electronic componentry thats particularly
>> > susceptible to electrostatic discharge? If a mobile phone is operated
>> > near such equipment/components, is there a risk of damage? Can the
>> > signal couple with a loop on a PCB and induce a voltage capable of
>> > destroying a sensitive device? eg. If you're modifiying your computer
>> > & receive a call on your mobile, is it actually possible to screw up
>> > your motherboard if you get too close to it?
>> >
>> > I've spoken to an Electrical Engineer about this, and we were unable
>> > to discount the possibility. If anyone knows more, please contribute.
>> >
>> > Thanks,
>> > Adam Gerlach.
>>
>>
>>
>
>

    The answer is pretty simple- for the most part, a cellphone will not
greatly affect electronic equipment, but they do present three potential
hazards.
    First, if they are operated close to other electronic devices, they can
induce voltages inside the semiconductors in those devices.  They can
disrupt operation (such as clearing the display on the gas pump) and the
vendor doesn't like that.
    Second, and conductor can act as an antenna, and a loop of conductor can
indeed produce a spark.  This is a remote but real possibility.  It doesn't
happen often, but I have observed it, and indeed the first experiments in
radio transmission showed how a spark could be produced at a distance.
Things are different now, but it can still be done.
    Third, as was mentioned in another post, a faulty battery contact (or
other metal to metal switch) can cause a spark and ignite gasoline vapors.
    While these are not very serious worries, mostly, they do present a
source of trouble.  I tend to avoid trouble myself- you live a little longer
that way.

Cheers!

Chip Shults

SPAM free Email - aichip@gdi.udu.net but remove the .baryon

    That is because of the inverse square law.  Here is a nice experiment
for you to try.
    Get a hand held radio or walkie talkie and put it next to a working CD
player.  Key it.  What do you see?
    In some instances you will see nothing, but in most, the CD will stop
playing and the display will read "error".  it is often necessary to power
the unit down completely before you can get this display to clear.
    Higher power levels can permanently damage the electronics.  You are
inducing voltages in the circuitry in two ways.  The first is good old
fashioned "antenna" activity.  The wiring and circuit traces are picking up
the RF and dumping the resulting voltages right into places that were not
meant to see such things.  The second is the fact that every non-linear
junction (diode, transistor, IC) in the device rectifies the RF and places
pulsating DC in the circuit.  They are acting as detectors.

Cheers!

Chip Shults

SPAM free Email - aichip@gdi.udu.net but remove the .baryon

    Consider that higher frequencies produce higher effective transient
voltages in circuitry.  At 50/60 hertz, there are many milliseconds fo the
voltage to rise.  At 400 megahertz and up, it happens in nanoseconds.  You
end up with higher voltages showing up in the wiring and the junctions.
    That is one of the crucial ideas behind EMP weapons and shielding.
Also, while power lines have higher field densities than cell phones, they
are quite a ways from you and the inverse square law holds.  The cell phone
can have a very low power output levelbut up close, it will utterly swamp
the power line signal.

Cheers!

Chip Shults

SPAM free Email - aichip@gdi.udu.net but remove the .baryon

If I turn Spread Spectrum off in my BIOS and leave my phone on top of my
computer case, my system will reboot when the mobile rings.

--------- BoganMan
[[ ICQ 32988117 ]]

>     Consider that higher frequencies produce higher effective transient
> voltages in circuitry.  At 50/60 hertz, there are many milliseconds fo the
> voltage to rise.  At 400 megahertz and up, it happens in nanoseconds.  You
> end up with higher voltages showing up in the wiring and the junctions.
>     That is one of the crucial ideas behind EMP weapons and shielding.
> Also, while power lines have higher field densities than cell phones, they
> are quite a ways from you and the inverse square law holds.  The cell phone
> can have a very low power output levelbut up close, it will utterly swamp
> the power line signal.

Or, in general the higher the transmitted frequency, the higher the voltage
per length of wire (like in transformers, volts/turn) - and in microwaves,
if you put in a half-burned match or toothpick, and turn it on (be sure to
have a glass of water for saftey if you want to try to possibly fry your
microwave by doing this), the charcoal conducts, and likewise is an antenna,
picks it up, arcs over, then apparently globs of plasma (which stay active
by acting as antennae themselves) will float off the toothpick and go about
the chamber, glowing, etc.

I've seen pictures of crazy people doing that, but wouldn't dare do it with
our microwave.  (Oh, what can be found on the internet...)

Tim

--
"NEVER SEND SPAM. IT IS BAD"
    - At bottom of some spam I got

Sort of on the subject.  When I was in the Marines we used to tie florescent
lamps to the tip of our radio transmitter antenna and it would
light up when we keyed the mic.

        At the risk of showing my age !!  These signs were created before
Transistors were invented circa 1948 ! At that time, it was quite common for
Mobile transmitters to run 100 to 1000 watts output in the Short Wave Bands
. . At these power levels it was quite possible to ignite blasting Caps
wired at a blasting Site ! Hence the Warning Signs to shut off the Mobile
Transmitters  at these constuction sites, and coincidentally at fuel Depots
! In the intervening 60+  years, we now seldom use Hi-Powered  mobile
transmitters, with the exception of a few misguided CB operators, even most
taxi's transmitters are under  50 watts. Our latest Cell Phones are all
under 1 watt, and operate in the UHF bands. In the Good Old Days, it was not
uncommon to get an RF burn off  of the transmitter's   microphone,  never
mind from the antenna !  Nowdays we transmit with the cell-phone antenna
pressed up against our ear!  What we are seeing  are Warning Signs from the
Vacuum Tube era posted in the  PC age, and it doesn't really make much
(any) sense at all, until you realize that these signs and rules and
regulations were created three generations ago to cover situations that no
longer apply.  You will occasionally see these signs posted in a room, right
next to the Staff Microwave Oven !!

        Yukio YANO

coincidentally  VE5 YS


"Adam" <hideo@tne.net.au> wrote in message
news:3b04d952.4676022@news.tne.net.au...
> Most of us have seen the warning signs at petrol stations telling us
> to switch off our mobile phones. Obviously, some people believe that
> the transmission from a mobile phone is powerful enough to induce a
> spark in a nearby object.
>
> What about sensitive electronic componentry thats particularly
> susceptible to electrostatic discharge? If a mobile phone is operated
> near such equipment/components, is there a risk of damage? Can the
> signal couple with a loop on a PCB and induce a voltage capable of
> destroying a sensitive device? eg. If you're modifiying your computer
> & receive a call on your mobile, is it actually possible to screw up
> your motherboard if you get too close to it?
>
> I've spoken to an Electrical Engineer about this, and we were unable
> to discount the possibility. If anyone knows more, please contribute.
>
> Thanks,
> Adam Gerlach.

    Perhaps this is an oversight, but you have omitted something very
relevant and important.  In those days, many electronic devices had vacuum
tubes and they are far less susceptible to this sort of damage.  Today,
semiconductors are the rule and they can indeed be damaged by the lower
power levels of today's cellphones.
    On top of that, the frequencies are higher and can cause more damage
with a given unit of power output.  And because of that, blasting caps can
still be ignited by small transmitters even at lower output power levels.  I
worked on missiles and defense ordnance at one point and any sort of
transmitting hardware was strictly and sensibly prohibited within a defined
radius due to the danger it represented.

Cheers!

Chip Shults

SPAM free Email - aichip@gdi.udu.net but remove the .baryon

 This entire thread continues to revolve about the idea that noise and
interference constitute increased possibility of damage.  That is just not so.
Just because RF radiation can interfere with operation does not mean that RF
will ever create damage.  Semiconductors are such susceptible to damage when
alone, but in systems they are resoundingly durable.   Just because the
operation can me interfered with by noise is absolutely no indication that it
will be damaged by increased noise.

  No properly designed electronics should be damaged by a mobile phone OR by
being adjacent to the powerful mobile phone base station.  This kind of damage
is so easy to avoid.  The amount of energy induced into leads and PC traces is
far below those implied in this thread.

"Sir Charles W. Shults III" wrote:

>     Perhaps this is an oversight, but you have omitted something very
> relevant and important.  In those days, many electronic devices had vacuum
> tubes and they are far less susceptible to this sort of damage.  Today,
> semiconductors are the rule and they can indeed be damaged by the lower
> power levels of today's cellphones.
>     On top of that, the frequencies are higher and can cause more damage
> with a given unit of power output.  And because of that, blasting caps can
> still be ignited by small transmitters even at lower output power levels.  I
> worked on missiles and defense ordnance at one point and any sort of
> transmitting hardware was strictly and sensibly prohibited within a defined
> radius due to the danger it represented.

    Not at all- the thread is still about whether a mobile phone (or other
small, similar transmitting device) can damage other electronics devices.
They can.  Other posters and I have given some examples that other readers
can duplicate.  This isn't about noise per se, it is about induced signals.
    A cellphone far from a tower can go to "high power" mode- four or five
watts.  Next to a CD player, a small transmitter with this sort of output
power can easily disrupt operation so that the unit must be powered down to
recover.  Some laptops with 3.3 volt processor cores can break into
"internal SCR" mode and burn out.  Many consumer devices can easily be
damaged by close proximity to such an RF level at the frequencies that
cellphones operate at.

>   No properly designed electronics should be damaged by a mobile phone OR
by
> being adjacent to the powerful mobile phone base station.  This kind of
damage
> is so easy to avoid.

    I agree with your opinion, but the catch phrase is "properly designed".
It becomes increasingly difficult to make cheap consumer electronics
"bulletproof" when we are each running around with a miniature microwave
transmitter shoved up against our head.

> The amount of energy induced into leads and PC traces is
> far below those implied in this thread.

    The average energy of the signal is low, sure.  The impulse levels are
not so tame.  And when a loop of wire printed on a circuit card or routed
through a case picks up a field with a density of 10 volts per centimeter, a
10 centimeter wire can "see" impulses of 100 volts.  Each junction is no
longer isolated also- in the ICs, each represents a tiny signal detector.
On top of that, there are parasitic junctions on the die- unintentional
"ghost" diodes and SCRs that can (when improperly stimulated) break into
conduction and continue to conduct once the signal is removed.
    If power is removed, they can switch off and operated normally most of
the time.  If not switched off in time, they can become tiny heating
elements or short circuits that will destroy the operation of the device.
    Now, imagine that a transient impulse of 30 volts is deposited at the
input of a CMOS logic gate that is operating on a 6 volt Vdd- many times,
the typical ESD protection will handle it nicely, but what if that transient
appears at the Vdd terminal?  You can't be certain that the device will
survive.  And at cellphone frequencies, you can get well isolated local "hot
spots" that can easily exceed 30 volts.
    Run your cellphone right next to your laptop or CD player next time and
see what happens.

Cheers!

Chip Shults

SPAM free Email - aichip@gdi.udu.net but remove the .baryon

123 <yano@home.com> wrote in message
news:ad2P6.5258$Ii.65924@news1.sshe1.sk.home.com...

>  At the risk of showing my age !!  These signs were
> created beforeTransistors were invented circa 1948 !

We certainly didnt have those signs at petrol stations all that time.

> At that time, it was quite common for Mobile transmitters
> to run 100 to 1000 watts output in the Short Wave Bands

Very uncommon indeed at petrol stations.

> . . At these power levels it was quite possible to ignite blasting Caps
> wired at a blasting Site ! Hence the Warning Signs to shut off the Mobile
> Transmitters  at these constuction sites, and coincidentally at fuel Depots !

Fraid not with retail petrol stations !

> In the intervening 60+  years, we now seldom use Hi-Powered
> mobile transmitters, with the exception of a few misguided CB
> operators, even most taxi's transmitters are under  50 watts.

> Our latest Cell Phones are all under 1 watt, and operate
> in the UHF bands. In the Good Old Days, it was not
> uncommon to get an RF burn off  of the transmitter's
> microphone,  never mind from the antenna !

Oh bullshit.

> Nowdays we transmit with the cell-phone antennapressed
> up against our ear!  What we are seeing  are Warning
> Signs from the Vacuum Tube era posted in the  PC age,

Wrong again. They only showed up at retail petrol stations
long after tubes stopped being used and well after CB too.

> and it doesn't really make much (any) sense at all, until you
> realize that these signs and rules and regulations were created
> three generations ago to cover situations that no longer apply.

Wrong again with retail petrol stations.

> You will occasionally see these signs posted in
> a room, right next to the Staff Microwave Oven !!

Pity what was being discussed was retail petrol stations.


> Adam <hideo@tne.net.au> wrote

> > Most of us have seen the warning signs at petrol stations telling us
> > to switch off our mobile phones. Obviously, some people believe that
> > the transmission from a mobile phone is powerful enough to induce a
> > spark in a nearby object.
> >
> > What about sensitive electronic componentry thats particularly
> > susceptible to electrostatic discharge? If a mobile phone is operated
> > near such equipment/components, is there a risk of damage? Can the
> > signal couple with a loop on a PCB and induce a voltage capable of
> > destroying a sensitive device? eg. If you're modifiying your computer
> > & receive a call on your mobile, is it actually possible to screw up
> > your motherboard if you get too close to it?
> >
> > I've spoken to an Electrical Engineer about this, and we were unable
> > to discount the possibility. If anyone knows more, please contribute.

On Thu, 24 May 2001 04:48:21 -0400, w_tom <w_tom1@usa.net> wrote:

> This entire thread continues to revolve about the idea that noise and
>interference constitute increased possibility of damage.  That is just not so.
>Just because RF radiation can interfere with operation does not mean that RF
>will ever create damage.  Semiconductors are such susceptible to damage when
>alone, but in systems they are resoundingly durable.   Just because the
>operation can me interfered with by noise is absolutely no indication that it
>will be damaged by increased noise.

snip

Perhaps I'm not correctly understanding what you mean; you seem
to be saying RF will not damage semiconductors? I would just
offer one word in response to that claim; EMP.

Jim (from Oz)

   How many have seen EMP?  How many nuclear blasts have you encountered lately?
What are the numbers associated with such fields?  The many examples are operations
interrupted (ie computer crashes) because a very strong signal was able to create a
minute voltage - a temporary interruption and no where near required for
semiconductor damage.

   We would do this often.  Open the steel cases and run transmitters inside the
system.  Only to make sure the design was solid.  Semiconductor damage was never
even a possibility - of course was never observed.  It was onlly performed to
verify the circuits were so properly designed at to even withstand RF noise.  What
radios are creating RF surges?

  The idea of EMP damage is all based upon speculation without numbers.  Using
those same logical processes, I can also prove that I can crack open the earth to
China.  If EMP creats damage, then EMP even does worse damage to semiconductor
designed to concentrate that EMP on transistor gates.  Sometimes an electronic
device is so poorly designed that it was crash or temporarily stop working because
of external fields.  But those interruptions are 100 or 1000 times too small to
cause semiconductor damage.

"Jim (from Oz)" wrote:

> On Thu, 24 May 2001 04:48:21 -0400, w_tom <w_tom1@usa.net> wrote:
>
> Perhaps I'm not correctly understanding what you mean; you seem
> to be saying RF will not damage semiconductors? I would just
> offer one word in response to that claim; EMP.

"w_tom" <w_tom1@usa.net> wrote in message news:3B0D8903.2486233E@usa.net...
>    How many have seen EMP?  How many nuclear blasts have you encountered
lately?
> What are the numbers associated with such fields?  The many examples are
operations
> interrupted (ie computer crashes) because a very strong signal was able to
create a
> minute voltage - a temporary interruption and no where near required for
> semiconductor damage.
>
>    We would do this often.  Open the steel cases and run transmitters
inside the
> system. Only to make sure the design was solid.  Semiconductor damage was
> never even a possibility

Since you're a numbers man, what kind of transmitters? What frequency(s)?
What signal strengths? How can you guarantee that it was "never even a
possibility".

I guarantee you, regardless of whether you take the covers off your mobile
phone or not, if you stick it in the microwave [DO NOT TRY THIS AT HOME], RF
energy WILL DESTROY semiconductors! (And just about everything else in the
phone too!).

My point is that it's a levels/frequencies based discussion.  Sure, there is
a background RF "noise" radiation present all the time. Sure electronics
goods should be designed to survive (in fact operate properly) at those
levels of RF.  But at the other end of the scale, you can (in theory) keep
cranking up the output of the RF, and eventually you will destroy
semiconductors.  I'm not saying they'll be the first components to fail, but
they will eventually fail.

David.

"Jim (from Oz)" wrote:
> 
> On Thu, 24 May 2001 04:48:21 -0400, w_tom <w_tom1@usa.net> wrote:
> 
> > This entire thread continues to revolve about the idea that noise and
> >interference constitute increased possibility of damage.  That is just not so.
> >Just because RF radiation can interfere with operation does not mean that RF
> >will ever create damage.  Semiconductors are such susceptible to damage when
> >alone, but in systems they are resoundingly durable.   Just because the
> >operation can me interfered with by noise is absolutely no indication that it
> >will be damaged by increased noise.
> 
> snip
> 
> Perhaps I'm not correctly understanding what you mean; you seem
> to be saying RF will not damage semiconductors? I would just
> offer one word in response to that claim; EMP.

EMP is a step-change in static magnetic field, caused by plasma
displacement of the earth's field by a large volume high-temperature,
high-speed blast.

It induces a few voltage/current spikes into circuits that form loops,
and damage by current happens to diode junctions, and damage by voltage
happens to mos junctions. Effective shielding is just a layer of alfoil.

It VHF and higher, most transistors/ICs are protected from direct
damage by junction capacitances. Damage is mainly caused by diode
rectification inducing DC offsets, causing the system to malfunction,
which then can damage components indirectly.

Mobile phones are very unlikely to cause direct damage to
semiconductors.

--
   ___                                           ___
  /  /\                                         /  /\
 /  /__\                                       /  /\/\
/__/   / Russell Shaw, B.Eng, M.Eng(Research) /__/\/\/
\  \  /  Victoria, Australia, Down-Under      \  \/\/
 \__\/                                         \__\/

  The most 'damage' we suffered was some millivolt changes on the long wire to
the weigh scale.  Millivolts don't create surge damage.  Those are the numbers
we saw.  We never say any major transients on oscilloscope displays.
Frequencies were shortwave single digit watt transmitters right against open
equipment, sub 1 watt VHF transmitter, and a 1 gigahertz battery operated
transmitter.  None created enough noise to crash the microprocessor.

  I am not making unsubstantiated claims of surge damage from mobile phones.  If
you make the claim, then please provide some supporting numbers.  I should warn
you that I keep putting this challenge up  and meet this same response - "I will
make the claim so you must refute it with numbers".  I would love just once to
see some numbers support these so many claims of EMP induced failures.  In
response to so many numerous claims for numbers, never once have these numbers
been provided.

  Noise interference does not prove an RF noise will damage the semiconductors.
It just proves that semiconductor operation can be interrupted by noise.  There
is a major voltage difference between noise induced interruptions and
destructive semiconductor failures.   Battery operated radio receivers are
constanlty interrupted by nearby lightning strikes and yet never suffer
damage.   If your E-M fields were so destructive, then why are the front end
transistors of sensitive radios not routinely damaged?  Let me suggest one
reason.  Those EMP fields required for such damage just don't tyipcally exist.

David Emrich wrote:

> "w_tom" <w_tom1@usa.net> wrote in message news:3B0D8903.2486233E@usa.net...
> >    How many have seen EMP?  How many nuclear blasts have you encountered
> lately?
> > What are the numbers associated with such fields?  The many examples are
> operations
> > interrupted (ie computer crashes) because a very strong signal was able to
> create a
> > minute voltage - a temporary interruption and no where near required for
> > semiconductor damage.
> >
> >    We would do this often.  Open the steel cases and run transmitters
> inside the
> > system. Only to make sure the design was solid.  Semiconductor damage was
> > never even a possibility
>
> Since you're a numbers man, what kind of transmitters? What frequency(s)?
> What signal strengths? How can you guarantee that it was "never even a
> possibility".
>
> I guarantee you, regardless of whether you take the covers off your mobile
> phone or not, if you stick it in the microwave [DO NOT TRY THIS AT HOME], RF
> energy WILL DESTROY semiconductors! (And just about everything else in the
> phone too!).
>
> My point is that it's a levels/frequencies based discussion.  Sure, there is
> a background RF "noise" radiation present all the time. Sure electronics
> goods should be designed to survive (in fact operate properly) at those
> levels of RF.  But at the other end of the scale, you can (in theory) keep
> cranking up the output of the RF, and eventually you will destroy
> semiconductors.  I'm not saying they'll be the first components to fail, but
> they will eventually fail.
>
> David.

w_tom <w_tom1@usa.net> wrote in message news:3B0D8903.2486233E@usa.net...
>    How many have seen EMP?  How many nuclear blasts have you encountered
lately?

    I have "seen" EMP a few times- it was my job to test the effects of
nuclear EMP on the Pershing II.  We had an EMP generator.  I can say
factually that EMP is real and not that hard to generate.  You do not need
nuclear weapons to do it.
    EMP is a generic term (acronym for electromagnetic pulse) and many
devices can cause it.  I later built devices specifically meant to
demonstrate this phenomenon at different levels.  You can do it on a fairly
small scale with some high voltage capacitors and a rapid discharge with
some real damage.  I mean permanent destruction of semiconductors.
    Just such a device would be a lightning gun (a type of Marx generator).
Even a large Van DeGraaf will do it.  There are companies developing small
mobile devices that will EMP a vehicle and stop it in high speed pursuits.
It uses a set of high voltage capacitors rapidly discharged against the
frame of the vehicle, and it often permanently destroys the on board
processor in the car.
    Now, back to brass tacks- a radio transmitter can indeed destroy
semiconductors with fairly low output power.  It is usually caused by
lengths of wire or other conductors that are attached to the semiconductor
in question.  These lengths can act as antennas that induce large voltages
in the junctions.  It is sen many times, but is often a difficult to
duplicate effect.  Still, this does not mean that it does not exist.

> What are the numbers associated with such fields?

    A typical nuclear EMP is on the order of a trillion watts for a few
picoseconds to a few nanoseconds.  It depends on the medium that it
encounters.  The first well known (and publically known) was the Hawaii
effects observed when a hydrogen bomb was detonated not far from the island.
There are roughly 50 exotic effects from such explosions, and EMP is only
one of them.
    High energy neutrons collide with the air molecules and lose a great
deal of energy from their momentum.  The result is electrons snapping back
into their orbitals all at once in a large region, creating a nearly
spherical plasma shell that acts as a radiating antenna.  The pulse is brief
but like a hammerblow compared to a pillow falling.
    Normal damage effects from EMP are from the high voltage field it
momentarily creates.  Numbers from 50 to 150 kilovolts per meter are common.
Testing is often done at a few hundred volts per meter.  Even though this is
"just a test", it can still destroy equipment very easily.  We had to use
all fiber optic lines to prevent losing our equipment.  I have lost too much
to transient effects in the course of my work already.  One was a rather
beefy power supply.

> The many examples are operations
> interrupted (ie computer crashes) because a very strong signal was able to
create a
> minute voltage - a temporary interruption and no where near required for
> semiconductor damage.

    Yes, that is what you are most likely to observe, but not a permanent
condition.  That is simple interference.  But under just the right (or
wrong) conditions, it can indeed destroy components.  Calculate the field
density of a transmitter at a given power and antenna configuration- you
will often see 3-5 volts per meter near the antenna.  This is for small
transmitters.
    What is this field?  Photons moving synchronously.  They are being
emitted as waves that cause electrons to oscillate rapidly in synch.  This
is the cause of a small voltage in the antenna that is then amplified in
your receiver.  But any conductive object can "see" an induced voltage due
to these synchronous electron motions.
    I don't know what you do for a living, but you certainly aren't a radio
transmitter technician because you would see that induced voltage spikes of
just a few volts can easily be made at some distance from a radio
transmitter.  To say that this just isn't going to happen is to not know the
facts.  There are now EMP weapons and while they remain fairly unreliable in
many uses, they are still viable for warfare.
    Yes, a layer of aluminum foil can usually be an effective shield to much
EMP, but when you also have cables running out of the box, you haven't
really shielded after all.  The antennas, data cables, power lines, and any
other long conductor will act as the conduit for the damaging signal, and
they are politely provided entrance right through any fancy metal case.
    Just something to get you thinking about it.

Cheers!

Chip Shults

SPAM free Email - aichip@gdi.udu.net but remove the .baryon

On Thu, 24 May 2001 20:37:19 +1000, "Rod Speed" <rod_speed@yahoo.com>
wrote:

[snip]
>> Adam <hideo@tne.net.au> wrote
>
>> > Most of us have seen the warning signs at petrol stations telling us
>> > to switch off our mobile phones. Obviously, some people believe that
>> > the transmission from a mobile phone is powerful enough to induce a
>> > spark in a nearby object.

It's actually nothing to do with transmission power, sparks, etc.

The idea is to save passengers, who wander around the forecourt chatting
on their mobiles, from being run over by the similarly distracted drivers.

I was going to add a smiley there, but then...

Chris

chris@heterodox.co.uk <remove second 'e' to email>

w_tom wrote:

>    How many have seen EMP?  How many nuclear blasts have you encountered lately?

1. That's like saying "Have you seen the wind?" You can't see it, only it's effects.
2. Well, India and Pakistan have been doing some underground tests lately.

> What are the numbers associated with such fields?  The many examples are operations
> interrupted (ie computer crashes) because a very strong signal was able to create a
> minute voltage - a temporary interruption and no where near required for
> semiconductor damage.
>
>    We would do this often.  Open the steel cases and run transmitters inside the
> system.  Only to make sure the design was solid.  Semiconductor damage was never
> even a possibility - of course was never observed.  It was onlly performed to
> verify the circuits were so properly designed at to even withstand RF noise.  What
> radios are creating RF surges?

Um, AM radio transmitters.

Just curious, what RF power levels were used? Were the transmission frequencies
calculated so that the tracks, traces and cable lengths would act like 1/4 wavelength
antennae? The test sounds like a "suck it and see" aproach anyway.

>   The idea of EMP damage is all based upon speculation without numbers.  Using
> those same logical processes, I can also prove that I can crack open the earth to
> China.  If EMP creats damage, then EMP even does worse damage to semiconductor
> designed to concentrate that EMP on transistor gates.  Sometimes an electronic
> device is so poorly designed that it was crash or temporarily stop working because
> of external fields.  But those interruptions are 100 or 1000 times too small to
> cause semiconductor damage.

True, but there is a fine line between what is considered a legitimate voltage registering
a legal logic level, and a voltage on that logic pin that will destroy the input. Have a look
at some of the datasheets of logic gates. Power supply rails aren't immune to transients either.
I suspect you are referring to what might be loosly termed "low level emp transients".
For the other extreme, I suggest having a look at this paper on E-bombs.

http://www.infowar.com/mil_c4i/mil_c4i8.html-ssi

It's also got a rough normalised diagram for the relative dv/dt's of a nuclear EMP transient,
a lightning stroke, and a Flux Compression Generator.

--
Regards

David Milne

  David has provided a good, laymens overview of electronic transient weapons in
   http://www.infowar.com/mil_c4i/mil_c4i8.html-ssi .
Some numbers are provided.  Cited, for example if the Flux Compression Generators which use 10^5 or
10^6 amps to create a magnetic field from megajoules of energy, concentrated in microseconds, and
then compressed by explosive energy.  IOW these numbers even exceed most lightning strikes by orders
of 10 or more.  And lightning power exceeds mobile radios by many tens of power ratios.  IOW to
create destructive EMP, the power and energy levels must well exceed anything existing in nature or
civilian life AND must occur within hundreds of yards.  Notice how much power and energy,
concentrated in one spot is required to possibly damage electronics.

  Furthermore David's artilce admits even then that unhardened equipment still may be difficult to
damage:
>The first is that target types are very diverse in their electromagnetic
>hardness, or ability to resist damage.  ...  various manufacturer's
>implementations of like types of equipment may vary significantly in
>hardness due the idiosyncrasies of specific electrical designs, cabling
>schemes and chassis/shielding designs used.
>The second major problem area in determining lethality is that of coupling
>efficiency, which is a measure of how much power is transferred from
>the field produced by the weapon into the target. Only power coupled
>into the target can cause useful damage.

  This article even suggests why fields from a nearby lightning strike do not typically damage
electronics.  "Second" suggests how poorly electromagentic fields couple their energy into PC traces
and IC leads.  Moreso, it demonstrates how impossible it would be for a mobile radio to create
damage to electronic equpiment.  Compare the energy and power levels required by EMP bombs to damage
even unhardened electronics - to energy of a portable radio.  Mobile radios create noise - which is
well below the voltage levels required to damage electronics.

 David has provided an informative piece on EMP weapons.

David Milne wrote:

> True, but there is a fine line between what is considered a legitimate voltage registering
> a legal logic level, and a voltage on that logic pin that will destroy the input. Have a look
> at some of the datasheets of logic gates. Power supply rails aren't immune to transients either.
> I suspect you are referring to what might be loosly termed "low level emp transients".
> For the other extreme, I suggest having a look at this paper on E-bombs.
>
> http://www.infowar.com/mil_c4i/mil_c4i8.html-ssi
>
> It's also got a rough normalised diagram for the relative dv/dt's of a nuclear EMP transient,
> a lightning stroke, and a Flux Compression Generator.

w_tom wrote:
> 
>    How many have seen EMP?

I own a coil gun.  If I shoot it near a cheap point and 
shoot camera I have the camera's flash will go off despite 
the camera being off.  The camera is now toast and can't 
take a good photo anymore.  It also causes disruptive effects 
on all TV tubes in operation near it.  It also disrupted 
my dad's cell phone when I was giving him a demo.  

Lightening can also produce EMP like pulses.

-- 
|  Bryan Andersen   |   bryan@visi.com   |   http://www.nerdvest.com   |
| Buzzwords are like annoying little flies that deserve to be swatted. |
|   -Bryan Andersen                                                    |