On Wed, 17 Mar 2004 13:33:06 -0800, Guy Macon wrote:

"John Michael Williams" wrote:

Thus, it appears it is not feasible to create a
hazardous spark with a CB at a gas station.

So, I think sliding over on a car seat, and thus generating a
possible static charge, would be more likely to ignite gasoline
vapor than talking on a cell phone while refueling.

Excellent set of experiments! I heartily approve of anyone who
does an experiment rather than taking someone's word.

Yeah. Amazing how much BS gets foisted on people.

Your methodology seems sound to me.

You might try putting a couple of drops of gasoline on a ceramic
plate and seeing if your wire is making a spark too small to see
but large enough to ignite the gasoline.

It's the vapor you want to try to ignite, so conditions will vary
depending on the wind. temperature, and pump rate which iis coutered
by the new vapor recovery systems installed on pumps.

I think the dangling plug wire is more dangerous than even smoking
at the pump. Ever throw a lit cigarette in a pail of gas. The cig
gets extinguished.

Another way of looking at it is with statistics. How many people
talk on cell phones while refueling? How many fuel fires occur?

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

|'Doc says...

|Turning off cell phones and radios seems like a reasonable
|precaution while fueling, I don't have a problem with that.
|I also don't understand why anyone else would either.

You don't understand why someone might be unwilling to miss
an incoming call when there is no apparent benefit?


--
Best Regards,
Mike

On Wed, 17 Mar 2004 13:33:06 -0800, Guy Macon wrote:
snip

|'Doc says...

|Turning off cell phones and radios seems like a reasonable
|precaution while fueling, I don't have a problem with that.
|I also don't understand why anyone else would either.

You don't understand why someone might be unwilling to miss
an incoming call when there is no apparent benefit?

Uh, a local Pastor's douche-bag wife recently backed over a BP
station clerk here (while he was measuring the pumps) and drove off.
He's in friggin' pain. Cops pulled the snotty bitch over and she
claimed she didn't know she'd run over him. Was it the cell phone or
the blaring xtian music?
--
Best Regards,
Mike

On Wed, 17 Mar 2004 21:50:35 -0600, Crazy George wrote:

IIRC, the Apollo capsule wire insulation was FEP, and was ignited when the
power conductor it insulated was mechanically pinched and shorted to ground.
It overheated enough from fault current to ignite before the breaker
tripped.

Kapton tape was blamed in the Swissair 400(?) cockpit fire and crash in
Newfoundland(?) a few years back.

Gasoline vapor fuel fires were ignited by early pagers and first generation
cell phones which used tiny universal motors with eccentric weights as
silent ring annunciators.

My Motorola Classic has one of those. What are they using now?

Find one of those old beasts and try running that
motor in a flammable environment.

OK

The technical basis of this is covered in a text: "Intrinsic Safety" by
Redding, published by Mc Graw Hill.


--
Best Regards,
Mike

"Active8" wrote
: Roger Gt wrote:
: "Paul Burridge" wrote
: : Jim Thompson wrote:
: :
: :I was struck by a thought when I heard the latest Palestinian
: :terrorist trick is to send a kid through the border with a
: back-pack
: :bomb triggered by a cell phone....
: :
: :The Israelis should get a telemarketer's speed dialer and
: constantly
: :dial away... boom... boom... boom...
: :
: :ROTFLMAO!
: :
: : Yes, I'm rolling on the floor laughing at all these deaths,
too,
: as
: : I'm sure we all are.
:
: Huh?
: He seemed to be laughing at the lame Idea! I also thought it
: funny that anyone would try something which would almost
totally
: wipe out the cellular phone service for the entire country...
:
: does a 200 station phone room with auto-dialers all calling one
: state wipe out POTs? WTH are *you* talking about?

Gee - Primitive! Not a Telephone guy I guess......
The last autodialer I worked on was a Dual DS3 line unit with a
router.
2 times 864 lines wide. A few of those would really choke a
network!

: All
: to provide a SMALL measure of confidence that no one had a
bomb
: attached to a phone. Like it would even work!
: WTH are you referring to? GAL!
:
: Best Regards,
: Mike

Active8 wrote:
[bombs]
Do you all think that tangos are dumb enough to trigger the bomb
with the ringer or would the detonator answer first and listen for a
DTMF sequence. Hmmm? Achmed the bomb maker gets a wrong number just
as he's connecting the thing.

I very much doubt they bother with DTMF decoders. I mean, how often do
you get a wrong number? I've had about 4 in my life. They'll just
connect the ringer (or vibrate function) to the detonator (with
whatever minimal circuitry in between is required - I've never used a
detonator!) and then only turn the phone on at the last minute.

It's not dumb to design a remote detonation system that requires the
absolute minimum of specialist knowledge and equipment to construct.


Tim
--
Love is a travelator.

Jim Thompson wrote:

I was struck by a thought when I heard the latest Palestinian
terrorist trick is to send a kid through the border with a back-pack
bomb triggered by a cell phone....

The Israelis should get a telemarketer's speed dialer and constantly
dial away... boom... boom... boom...

You would have to have every phone in the nation ring every couple of
hours. They're not going to be stupid enough to have the phone both
switched on and connected to the bomb until the last minute.


Tim
--
Love is a travelator.

Guy,
I don't understand why anyone would have a cell phone
stuck in their ear every waking moment, especially in a
car, or while fueling, or in a number of other places
where I've seen them. They can be and are a hazard while
driving, and a real P.I.T.A. in public places. (Hurray for
the states that passed a 'no cell phone while driving' law!)
Seriously, how many ~important~ calls have you ever had on
your cell phone when in a public place, or while driving
that couldn't have waited? Cell phones should be water
soluble, or biodegradable...
'Doc

'Doc wrote in message ...
John,
It's also possible to start a fire rubbing two sticks
together, but it isn't as likely to be an accidental thing.
I would tend to doubt any claims about cell phones starting
accidental fires unless there has been some modification
to the phone, or other unusual circumstance. Turning off
cell phones and radios seems like a reasonable precaution
while fueling, I don't have a problem with that. I also
don't understand why anyone else would either. Do I turn off
my two way radio when fueling? Yes, but mainly because of
how it's connected (ignition switch).
If fuel vapor liable to ignite because of RF? Not unless
the RF field is very strong, or the antenna arcs for some
reason. Very likely? Not really. Possible? Sure. So using
a little common sense... what's the problem?
'Doc

PS - Cross posting is a sure way of causing misunderstandings.


I was just trying to add some factual information to the
link I gave, which was just a lot of rumor--both pro and con
RF hazards. Check it out.

From time to time, I read postings about people complaining
about others gabbing on a cell phone while (self-serve)
refueling.

I don't follow what you say about cross-posting. I'm not a ham
operator, so if I am making some obvious mistake, I thought
adding the antenna group would get a correction. Is that your
interest?

Hopefully, this thread will end up by putting to rest
fears of cell phones around gas stations, at least from the
RF standpoint. Also, if I'm wrong, and there IS danger
from the RF, someone should be able to correct me. Either way,
it's an interesting topic, don't you think?

John

John Michael Williams

On Thu, 18 Mar 2004 05:39:21 +0000, Tim Auton
tim.auton@uton.[groupSexWithoutTheY] wrote:


Do you all think that tangos are dumb enough to trigger the bomb
with the ringer or would the detonator answer first and listen for a
DTMF sequence. Hmmm? Achmed the bomb maker gets a wrong number just
as he's connecting the thing.

I very much doubt they bother with DTMF decoders. I mean, how often do
you get a wrong number? I've had about 4 in my life. They'll just
connect the ringer (or vibrate function) to the detonator (with
whatever minimal circuitry in between is required - I've never used a
detonator!) and then only turn the phone on at the last minute.

It's not dumb to design a remote detonation system that requires the
absolute minimum of specialist knowledge and equipment to construct.



To use the unique cellphone ID to detonate a remote bomb is actually
a very ingenious innovation. No timers to mess with. The terrorist
has full and instant control of the time and place to set off the
bomb.

As Tim says its relatively easy to connect the ringer wires to a
simple circuit to output enough juice to trigger the detonator. Frist
year student project - like using a battery to keep a capacitor
charged and the ringer closes the discharge switch. Boom.

The countermeasure I think, is fairly simple. Every vulnerable public
place which may be targeted by terrorist bomb attacks, should install
cellphone signal blockers.

I believe these are already available and smart dining places and
concert halls have them so that their patrons won't be interrupted by
cellphones. I'll skip the arguments, mostly from cellphone service
providers, against signal blockers that may cause doctors and
emergency workers to miss their calls. Until some better solution
comes along I think this is a good solution. (Hint. Buy shares in
signal blocker companies.) If this suggestion is taken up perhaps
we'll get some peace from those incurable cellphone yakkers who think
the world wants to hear every word they say anywhere.

"KLM" wrote in message
...
On Thu, 18 Mar 2004 05:39:21 +0000, Tim Auton
tim.auton@uton.[groupSexWithoutTheY] wrote:
The countermeasure I think, is fairly simple. Every vulnerable public
place which may be targeted by terrorist bomb attacks, should install
cellphone signal blockers.

Not in the US. Intentional interference is illegal. It likely is in most
places.