Julian Macassey <julian%bongo.UUCP@nosc.mil> (05/21/91)
In article <telecom11.368.2@eecs.nwu.edu> Mike Spann <mikes@gammalink. com> writes: > Digging way back into my memory, I do remember a story (maybe even > true) where police officers were told not to dump their spare bullets > into the same bag as their hand held radios. The story I was told was > that should the push-to-talk button be pressed, the electro-magnetic > waves could cause a round to go off. When pressed to explain, their > technical expert said that the oxides between the primer and the case > could act as a rectifier at 150 MHz, and convert some of the five watts > of radio energy into a DC voltage. > Supposedly, this DC voltage could set off the primer and therefore the > bullet. There was a case in Florida (Miami I beleive) where a cop put his walkie-talkie spare battery pack and bullets in the same pocket. The internal resistance of NiCad batteries is very low which means they can pump lots of current through a bullet. The heating is enough to detonate the bullet. In fact I have met a couple of people who were badly burned when loose change shorted out a spare battery pack in a pocket. Also I doubt 150 Mhz RF would flow in a bullet which is hardly resonant at 150 Mhz (2 Meters). Julian Macassey, n6are julian@bongo.info.com ucla-an!denwa!bongo!julian 742 1/2 North Hayworth Avenue Hollywood CA 90046-7142 voice (213) 653-4495
Brian Kantor <brian@ucsd.edu> (05/22/91)
My RCA TacTec walkie burned my wrist one day when I managed to
accidently brush my watch band against the battery charging contacts,
and the high current through the resulting short circuit heated up the
metal band quite quickly.
I can easily believe that a bullet could be detonated in much the same
way.
My Motorola and GE radios cannot do that, for they have a blocking
diode inside the battery pack that prevents the battery from
discharging through the external contacts -- clearly a better design.
In the early days of two-way radios, some vacuum-tube mobile
transmitters used motor-generator sets ("dynamotors") to produce the
600 or so volts needed in the power output stages. In one memorable
incident, a CHP officer transmitted while his car was being fueled,
and the motor brush sparks ignited the gasoline fumes in his trunk
(where the radio was installed), blowing the trunk lid off the car and
ruining the overhanging gas station canopy. The radio continued to
work, of course.
Brian