Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx> At 04:23 PM 3/20/2007, you wrote:
Original poster: "Gerry Reynolds" <gerryreynolds@xxxxxxxxxxxxx> Hi Jim,To add to what you are saying, I believe the there are two radiation mechanisms with a TC. One is the radiation of the fundamental resonant frequency (50-200KHz) and its harmonics or overtones. This mechanism probably has the highest energy/bandwidth concentration and fortunately the radiation efficiency is very very small due to the physical dimensional comparisons to the corresponding wavelengths. The other mechanism is due to the impulse of energy transferred when the spark gap fires, streamers breakout, or a power arc hits a grounded target. For this case, one can convert the time based impulse waveform into its spectral components (Fourier transform) and find that the energy is spread out over a wide frequency band (over all frequencies if an ideal impulse or delta function) so any one frequency has little energy in it.
Yes.. this is in fact the case. There's also a kind of resonance effect for the length of the spark. For instance, lightning shows a strong signal at around 80 MHz, correlated to the jump size as the stroke develops.
Gerry R.Original poster: Jim Lux <jimlux@xxxxxxxxxxxxx> At 09:32 PM 3/18/2007, Tesla list wrote:Original poster: "earl rhodes" <earl_1975@xxxxxxxxxxxxx> hi allisnt it possible the report is correct ?? cheap radios suffer serious bleedover from other radio sources !! im not ham i was citizen band ! surely police radio isnt very high quality mor just summat that works !!Nope.. commercial land mobile radio is required to meet certain performance standards, just to be legally sold. And, then, while the local gendarmes aren't wealthy, they aren't that cost sensitive, that they would cheap out on the radios.crap!! so does anybody know the frequencys were talking about !!In the U.S., the police generally use low VHF (30-88 MHz, highway patrol, forest service), high VHF (150-174 MHz), or UHF (400+ MHz) and some 800 MHz trunking stuff these days.A TC will put out some VHF power (as Terry Fritz measured a decade ago or so), but not all that much. It's also spread over a very wide bandwidth, so even if the total power is high, the power in any one channel is very low.