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Re: EMP =- PULSED PHONE DESTRUCTION!
>Original Poster: Jim Lux <James.P.Lux-at-jpl.nasa.gov>
>
>Tesla List wrote:
>
>2.2 uF * (2300*1.414)^2 / 2 = about 11 Joules stored energy. If it
>dissipated in a couple of microseconds (a reasonable guess, if you had
a
>few uH parasitic L in the circuit), the peak power is 5-10 MW. This
>would be fairly loud (nothing like, say, a gunshot though, with
hundreds
>or thousands of J being dissipated).
REALLY? Could you tell that to my next door neighbour next time he
calls the police? :-).
Just for grins, you should
>calculate the peak current in the wire loop (roughly VC/L or a few kA)
,
>and from that you can calculate the EM field strength produced by the
>impulse. (as a start, 1 kA around a 1 m diameter loop gives H=1000 A/m,
>B is then H*1.25E-6 = about 1 milliTesla or 10 Gauss.)
>
>Looking at the problem another way, how much of the energy was coupled
>into the receiver. Assume the receiver was a meter away from the "point
>source", and that the receiver was about .1 m in diameter (about .008
>square meter area). Your receiver intercepts about 1/1600 of the power
>radiated (if it was uniformly radiated, which is hardly likely). If we
>want to be optimistic, say your receiver saw a peak power intercepted
of
>about a kilowatt (for a very short time, though, the energy would be a
>few millijoules). If you were really unfortunate and all the power
>happened to be in the bandwidth of the receiver, that kW corresponds to
>a few hundred volts, which is enough to blow up the transistors, even
if
>it does only last a few microseconds.
The spark gap consisted of 2 bolts. Therefore the energy would be
concentrated between the bolt heads and therefore it would not radiate
in all directions, but only in front of the bolts.
The phone was closer than 1m. It was more like 20cm distance. The phone
shuts down by itself at 1m distance…
>I am surprised that it damaged the phone, though. Perhaps your LC
>circuit was resonant at just the right frequency to match that the
phone
>receiver's front end and blew up the first stage. I'd be interested to
>know the make and model of the phone and the handset receiver frequency
>(1.6 MHz, 49 MHz, or 900 MHz). A schematic of the receiver would be
even
>more interesting.
I don’t have the manual for the phone and it doesn’t say anywhere the
frequency. I would send you a diagram but I don’t have one either.
The phone is a standard PTT TELECOM (the Dutch Phone Company) model. I
have no more info on it… The antenna is about 1m long… (Telescopic)
>> Since Tesla Coils use a circuit very similar to this one
(discharging
>> large capacitors trough spark gaps), they should have similar
effects. I
>> have never seeing any mention of this anywhere, but perhaps the
>> interference produced by TCs is due to their spark gaps, not the
>> secondary. I am sure at least some of it is...Perhaps shielding the
>> spark gap with metal would reduce the interference produced by the
Coil.
>
>The EMP power is radiated by the wires in the circuit, not the gap
>itself, so shielding the gap would make no difference.
What makes you so sure???
From my experience, whenever there are sparks, there is interference. A
TV cascade will interfere with a phone when it sparks. Ignition coil
circuits, leiden jars… You name it!
Most of them produce very little interference and are hard to notice.
That’s why I didn’t expect the results to be so dramatic with my phone…
I think when a spark occurs it sends off electromagnetic waves in all
directions. It makes some sense. I think I know why, but I can’t really
put it into words. Maybe you can help me with that…
Still. Maybe most of the TC interference comes from the wiring. But I
am quite confident some of it is coming from where you don’t expect it:
Your spark gap….
Thanks for replying so fast!
Sam.
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