CB Radios, Cellphones and Gasoline Vapor Ignition

[Wim Ton]

One thing that may set off a detonator is a RF field with a wavelength in
the order of the detonator leads.

From the time I worked with detonators on oilrigs, an absolute radio-silence
was required till the charge was safely lowered down the borehole.

Wim

 

[Active8]

On Thu, 18 Mar 2004 10:30:45 GMT, Dave Head wrote:

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

Active8 <reply2group@ndbbm.net> 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

New anti-terrorist weapon => telemarketers. They call everybody. Should wipe
out the bomb makers in about a week.

Dave Head

Not if they're on the Do Not Call list
--
Best Regards,
Mike

 

[Jim Yanik]

Tim Auton <tim.auton@uton.[groupSexWithoutTheY]> wrote in
news:4ndi50loirkshdi00l8eh03qfrk1pjrli5@4ax.com:

Jim Thompson <thegreatone@example.com> 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

Actually,they have to have it active before they enter 'enemy' territory,as
citizens there often notice some stranger fiddling with a package and then
leaving it behind;the common indicator a bomb has been placed.

--
Jim Yanik
jyanik-at-kua.net

 

[KLM]

On Thu, 18 Mar 2004 00:59:41 -0800, "CW" <clinton.magers@comcast.net>
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.

Homeland security has done worse on civil liberty laws.

Compared to the cost and unfeliability of security personnel and
person-body checks surely a "cellphone safe" building, train or public
conveyance is acceptable. After all it wasn't that many years ago
(~10) when there were no cellphones. The what did emergency workers
do then? What happend when you are out of cellphone range? Have you
actually heard of anyone dying because the party called couldn't get
his/her cellphone page?

I would certainly feel a lot more comfortable if the building
advertises itself as a cellphone free location to a point where I
would prefer to shop there. A work around for emergency worker
phone access is for the emergency worker to tell a service provider
that he is at a particular cellphone free location. If he needs to be
contacted the service provider will phone that building(s) management
by landline who will then page the emergency worker. It will work
like a 911 line and is meant for emergencies only, not a mom looking
for a shopping mall crazy daughter. Outside these cellphone free
buildings any cellphone will work normally.

 

[S]

the show on discovery channel, mythbusters. debunked that myth,


"John Michael Williams" <jwill@AstraGate.net> wrote in message
news:4032bf27.0403171202.f93e639@posting.google.com...

Claims that people have started fires by using
their cell phone while refueling a car apparently
are false: See
http://www.snopes.com/autos/hazards/gasvapor.asp
and other sites.

However, the first radios transmitted
sparks, so in principle it should be possible to
transmit near a long wire separated by a small gap from
ground or another wire and get a small spark. So, I
decided to try an experiment.

I don't use a cell phone, so I assumed a CB radio
transceiver would be a reasonable substitute: The
power output of a nominal 5 W CB also is consistent
and nonadaptive, so a possible unknown (actual output
power) is avoided. Cell phones are adaptive and
not very consistent in power output, so power
should be monitored during a cell phone experiment.

5 W is considerably more than the 0.2 to 2 W typically
possible from a cell phone; the power should be the
important factor, although maybe someone should repeat this
experiment with a cell phone, which would operate at
a much higher frequency.

I used a Radio Shack TRC-231 handheld (stock #21-1675)
with xmit power on high and set on Channel 40.
The antenna was the one that came with it (about 25 cm
long). I set the volume to max and the squelch at min
to be able to detect anyone else trying to use the
channel; this was just to be sure that my brief, silent
transmissions would not interfere with anyone.

I used the CB indoors, in a mostly metal-shielded
room. Because CB wavelength is around 10 m, everything I
did was in the near field; however, the inverse square law
for power still holds, allowing that the CB antenna is more
of a line than a point source under my conditions below.


The first thing I noticed was that every time I keyed the
transmit button, the CB would switch the
light level of a nearby touch-dimmed lamp, and it
made a Microalert microwave detector scream. I unplugged
the lamp and turned off the Microalert.

Then, I tried to light a 120VAC indicator neon lamp attached
to two solid copper switchback wires totalling about 1 m
long, so the lamp was in the middle effectively of a dipole
antenna. I tested the lamp and found it would light with
10 microamps current. The CB had no effect, even if held
parallel to, and almost touching, the wires. Thus, the near
field of a 5 W CB radio can not supply about 90 V at even
10 uA, under these conditions.

I then attached a 1.2 m monopole antenna to an oscilloscope.
This antenna has a Schottky hot carrier diode and impedance
matching resistors builtin. It's home made, but it's probably
as good as any other wire about that long. I hooked
the antenna coax to an oscilloscope: With the CB transmitting,
and its antenna parallel and 1 m away from the monopole,
the amplitude was about 100 mV p-p, at 27 MHz or so. I could
not get more amplitude no matter how close I held the CB,
or at what angle. Touching the bare monopole wire increased
the amplitude by no more than 10%.

So, first conclusion: To get even a 1 V spark would take a
wire at least 9 m long, all somehow kept within 1 m of the
transmitter. Thus, it appears it is not feasible to create a
hazardous spark with a CB at a gas station.

Just to be sure, I taped a 1 m wire to a table top in the dark
and slowly brought it closer and closer to another wire
plugged into a wall socket 3rd wire ground (yes, I verified
that the socket was wired to ground first!). At each distance, I
briefly keyed the CB. I could not see any spark, even after
dark-adapting my eyes for 10 min and letting the wires touch.
I might have dark-adapted longer, but I don't know whether
I should have been able to see a 50 mV spark or not.

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. However, it
would be useful for someone to repeat this kind of test with an
actual cell phone, as opposed to a CB radio. The wires should
be shorter, for one thing . . ..

I'm cross posting to an antenna group, looking for criticism.

John
jwill@AstraGate.net
John Michael Williams

 

[Richard Henry]

"KLM" <klmok88@yahoo.com> wrote in message
news:b1vj5019oq4of5qqdgphso6k3ik9t3siq1@4ax.com...

Compared to the cost and unfeliability of security personnel and
person-body checks surely a "cellphone safe" building, train or public
conveyance is acceptable. After all it wasn't that many years ago
(~10) when there were no cellphones. The what did emergency workers
do then? What happend when you are out of cellphone range? Have you
actually heard of anyone dying because the party called couldn't get
his/her cellphone page?

I'm old enough to remember when doctors would register with security when
they went to a baseball game. There was always at least one announcement
per game - "Dr. 31, call your service."

 

[Dirk Bruere at Neopax]

"Jan Panteltje" <panteltje@yahoo.com> wrote in message
news:d75ca6e4.0403180818.2541c52b@posting.google.com...

"Terry Given" <the_domes@xtra.co.nz> wrote in message
news:<MJc6c.8716$rw6.174739@news.xtra.co.nz>...

a better technique would be for the israeli government to pull their
heads
in, and start acting like humans instead of nazis (deliberate
comparison - I
am continually astounded that this behaviour comes from a people who
survived the Holocaust - surely the darkest moment in human history).

Actually, the Tasmanian natives might consider their plight to be somewhat
worse.
Assuming that they still existed, of course.

--
Dirk

The Consensus:-
The political party for the new millennium
http://www.theconsensus.org

 

[CW]

You can try to ratioanlize it as much as you want. The willfull electronic
interference of a radio service is a crime. Did you read the part of my post
about signal blocking? I thought not. Go back and try again. If a terorist
is going to strike, he is going to strike. The Department of Homeland
Paranoia is not going to be able to do anything about it.


"KLM" <klmok88@yahoo.com> wrote in message
news:b1vj5019oq4of5qqdgphso6k3ik9t3siq1@4ax.com...

On Thu, 18 Mar 2004 00:59:41 -0800, "CW" <clinton.magers@comcast.net
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.


Homeland security has done worse on civil liberty laws.

Compared to the cost and unfeliability of security personnel and
person-body checks surely a "cellphone safe" building, train or public
conveyance is acceptable. After all it wasn't that many years ago
(~10) when there were no cellphones. The what did emergency workers
do then? What happend when you are out of cellphone range? Have you
actually heard of anyone dying because the party called couldn't get
his/her cellphone page?

I would certainly feel a lot more comfortable if the building
advertises itself as a cellphone free location to a point where I
would prefer to shop there. A work around for emergency worker
phone access is for the emergency worker to tell a service provider
that he is at a particular cellphone free location. If he needs to be
contacted the service provider will phone that building(s) management
by landline who will then page the emergency worker. It will work
like a 911 line and is meant for emergencies only, not a mom looking
for a shopping mall crazy daughter. Outside these cellphone free
buildings any cellphone will work normally.

 

[John Woodgate]

I read in sci.electronics.design that CW <clinton.magers@comcast.net>
wrote (in <UtKdnXVNibo6kMfdRVn-uA@comcast.com&gt about 'Cellphones and
Bombs', on Thu, 18 Mar 2004:

You can try to ratioanlize it as much as you want. The willfull
electronic interference of a radio service is a crime. Did you read the
part of my post about signal blocking? I thought not. Go back and try
again. If a terorist is going to strike, he is going to strike. The
Department of Homeland Paranoia is not going to be able to do anything
about it.

I am ALMOST old enough to remember a similar idea held in UK and Europe
before WW2, that 'the bomber (aircraft) will always get through'. The
RAF pretty well disproved it.

There is a finite probability that an individual terrorist, acting
completely alone, might evade all the checks. But it's far more
difficult for members of a terrorist cell to evade detection.
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

 

[Zak]

Terry Given wrote:

The current situation exists, time doesnt flow
backwards, and if a real solution is not found, the terrorism will not only
continue, but will coninue to get worse. Neither side seems interested in
moving forward though, they are caught up in an ever-escalating round of
murderous tit-for-tat.

OT, but I have to say I fully agree. This will also take away a lot of
the breeding grounds of war-mongering terrorist organizations that seek
islamic/arabic support.

If only...


Thomas

 

[Reg Edwards]

I AM old enough to remember the pre-war and the phoney-war impressions of
the population of the cities of Birmingham and Coventry about the
capabilities of the Luftwaffer.

It was "They'll never get this far."

At the same time the citizens of Cologne, Hamburg, Berlin and Dresden were
saying much the same thing.

 

[Dirk Bruere at Neopax]

"John Woodgate" <jmw@jmwa.demon.contraspam.yuk> wrote in message
news:eRbCCRJiMhWAFwYo@jmwa.demon.co.uk...

I read in sci.electronics.design that CW <clinton.magers@comcast.net
wrote (in <UtKdnXVNibo6kMfdRVn-uA@comcast.com&gt about 'Cellphones and
Bombs', on Thu, 18 Mar 2004:
You can try to ratioanlize it as much as you want. The willfull
electronic interference of a radio service is a crime. Did you read the
part of my post about signal blocking? I thought not. Go back and try
again. If a terorist is going to strike, he is going to strike. The
Department of Homeland Paranoia is not going to be able to do anything
about it.

I am ALMOST old enough to remember a similar idea held in UK and Europe
before WW2, that 'the bomber (aircraft) will always get through'. The
RAF pretty well disproved it.

They did not disprove it.
All they disproved is the notion that a war can be won by air power alone.

--
Dirk

The Consensus:-
The political party for the new millennium
http://www.theconsensus.org

 

[KLM]

On Thu, 18 Mar 2004 13:00:55 -0800, "CW" <clinton.magers@comcast.net>
wrote:

You can try to ratioanlize it as much as you want. The willfull electronic
interference of a radio service is a crime. Did you read the part of my post
about signal blocking? I thought not. Go back and try again. If a terorist
is going to strike, he is going to strike. The Department of Homeland
Paranoia is not going to be able to do anything about it.

And cellphone signal blocking is localized, short range, same as WiFi.
Put up a sign to that effect in your business premise. Those who feel
they must have their cellphone access 24/7 can always step outside
the door or avoid the place. That business will survive because there
are a miniscule number of 24/7 cellphone freaks.

Anyway the use of cellphones while driving is banned in many states in
the US and worldwide. What is so different in banning their use in
selected public places. The only difference is that signal blocking
is applied universally in that defined building area, and without
having intrusive checks being made on anyone to effect compliance.

 

[Dirk Bruere at Neopax]

"Terry Given" <the_domes@xtra.co.nz> wrote in message
news:L4q6c.9357$rw6.186585@news.xtra.co.nz...

"Dirk Bruere at Neopax" <dirk@neopax.com> wrote in message
news:c3d1ra$266002$1@ID-120108.news.uni-berlin.de...


"Jan Panteltje" <panteltje@yahoo.com> wrote in message
news:d75ca6e4.0403180818.2541c52b@posting.google.com...
"Terry Given" <the_domes@xtra.co.nz> wrote in message
news:<MJc6c.8716$rw6.174739@news.xtra.co.nz>...

a better technique would be for the israeli government to pull their
heads
in, and start acting like humans instead of nazis (deliberate
comparison - I
am continually astounded that this behaviour comes from a people who
survived the Holocaust - surely the darkest moment in human
history).

Actually, the Tasmanian natives might consider their plight to be
somewhat
worse.
Assuming that they still existed, of course.


dont they have a nice monument though?

Probably not - they have no political pressure groups.

--
Dirk

The Consensus:-
The political party for the new millennium
http://www.theconsensus.org

 

[Terry Given]

"Dirk Bruere at Neopax" <dirk@neopax.com> wrote in message
news:c3d1ra$266002$1@ID-120108.news.uni-berlin.de...

"Jan Panteltje" <panteltje@yahoo.com> wrote in message
news:d75ca6e4.0403180818.2541c52b@posting.google.com...
"Terry Given" <the_domes@xtra.co.nz> wrote in message
news:<MJc6c.8716$rw6.174739@news.xtra.co.nz>...

a better technique would be for the israeli government to pull their
heads
in, and start acting like humans instead of nazis (deliberate
comparison - I
am continually astounded that this behaviour comes from a people who
survived the Holocaust - surely the darkest moment in human history).

Actually, the Tasmanian natives might consider their plight to be somewhat
worse.
Assuming that they still existed, of course.

dont they have a nice monument though?

 

[Mark Fergerson]

Jan Panteltje wrote:

<snip>

unfortunately its not likely to happen. Little things like the clearly
observable FACT that decades of repressive behaviour towards the
palestinians has NOT resolved the problem, but made it WORSE, seem to have
escaped the notice of successive israeli governments. so much for "an eye
for an eye" being of any practical use.

Um, Israel is backed up against the Mediterranean. What
impenetrable barrier are the "Palestinians" backed up against?

Mark L. Fergerson

 

[Cecil Moore]

Terry Given wrote:

dont they have a nice monument though?

Terry, what the heck are you doing awake at 2am tomorrow?
--
73, Cecil http://www.qsl.net/w5dxp



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

 

[CW]

Damn sight bigger target and there are not a lot of hiding places in the
sky. In any case, you are talking about a miniscule little country. Try to
keep an eye on this one.

I am ALMOST old enough to remember a similar idea held in UK and Europe
before WW2, that 'the bomber (aircraft) will always get through'. The
RAF pretty well disproved it.

There is a finite probability that an individual terrorist, acting
completely alone, might evade all the checks. But it's far more
difficult for members of a terrorist cell to evade detection.
--
Regards, John Woodgate, OOO - Own Opinions Only.
The good news is that nothing is compulsory.
The bad news is that everything is prohibited.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

 

[KLM]

And cellphone signal blocking is localized, short range, same as WiFi.
Put up a sign to that effect in your business premise.

An idea just occurred to me.

You notice those electronic anti-shoplifting interrogators at the
checkout counters?

Why not include a circuit in every cellphone that will cause the
answer bell to ring when anyone carrying a cellphone crosses one of
these interrogators. Maybe have the circuitry activate a different
ring tone or ring pattern from the normal call ring. Its extremely
short range and won't interefere with normal cellphone use.

It will set off a cellphone bomb or at least ID a suspicious cellphone
owner who can be asked to show the phone (any cellphone modifications
will be noticed immediately) or can be called aside for further
inspection. This will enable security people in places like train
stations, bus stations and airports to quickly screen crowds.

The same interrogating circuitry could be installed in metal detector
security gates.

Its rare to be able to go anywhere without encountering one of these
interrogators these days. A bomb carrying cellphone triggered
terrorist will have a hard time moving around without attracting
attention somewhere.

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

On a different discussion point, picture the recent Spanish train
bombings (10 set off.) Had the train installed cellphone signal
blocking equipment most of those bombs would probably not have been
set off. Calls on emergency workers commuting by train could easily
have been relayed by the train's onboard PA system. Calls out can be
made from on-board public pay phones. Or can the signal blocking be
effective only for incoming calls and leave out going calls
unrestricted? Airlines blocks incoming calls. Outgoing calls can be
made from anywhere during flight through the aircraft's phone system.

 

[KLM]

On Thu, 18 Mar 2004 16:53:28 -0800, "CW" <clinton.magers@comcast.net>
wrote:

Do you know what the word ILLEGAL means? It is very obvious that you are
ignorant of the technical details and I am not going to be your electronics
teacher. It is illegal for a reason.

Terrorists are using cellphones to kill and maim hundreds of people
and you are maintaining that unrestrcted CP use is a god given
inviolable right.

I'd rather hear your "reason" than to argue with you about the
technical details. If the rationale for public safety is there, the
laws can be changed. Maybe you should tell to us what this cast- in-
concrete law is and that will save us a lot of guesswork and
rebuttals.