.... no need, I have seen the results of such devices in practical
operation...

I do a class at the jr. college here, have 3 sons in the computer field,
my garage is a clubhouse/wireless point/computer lab...

.... lot of cs/electronics majors... they have fired up such devices
before I said, "Not here!!!"

Really got ****ed when it jammed my "late night talk radio" which I fall
asleep to...

Warmest regards,
John

"Frank" wrote in message
news:37_re.49668$wr.42366@clgrps12...
"John Smith" wrote in message
...
... if I was to attempt to jam that broad of range of freqs, I would
couple it to a waveguide which exhibited resonance on that whole
spectrum (feed the center of circular guide/"modified horn" with
shortest point to edge of circle resonant at 2.4 ghz resonant,
longest point to edge of circle resonant at 800 mhz) , feeding the
magnetron a ramp or triangle dc voltage/current of 1 mhz freq--is
going to generate harmonics until the cows come home... I would feel
like Dr. Frankenstein when the neighbors showed up on my door step
with their pitchforks and scythes!!!

Warmest regards,
John

Not sure how the magnetron would respond to a ramp, but at some
amplitude the magnetron would cease oscillations. The fact is that
the harmonic decay of a sawtooth waveform is slightly higher than a
rectangular pulse. A worst case analysis would involve a rectangular
pulse with a finite rise/fall time. If for example the magnetron were
pulsed with a square wave, 50% duty cycle, at 1 MHz, with a rise time
of 10nS, the 1,600 th harmonic (i.e. lower sideband at 800 MHz)
amplitude is about -50 dBC. This result is obtained from the solution
of the products of two Sa(x) functions involving the rise time,
period, and pulse width of a symmetrical trapezoidal waveform. If you
have a burning desire to know, I can vary the parameters of rise time,
pulse width, etc. to see how the spectral shape changes.

These sidebands, in the vicinity of 800 MHz, are therfore of
significant amplitude. I am, however, fairly certain that 800 MHz is
below the waveguide cut-off frequency. I will try and measure the
dimensions of a typical oven waveguide to determine its cut-off
frequency. The other factor is the Q of the magnetron cavities how
would this effect the banwidth of the spectrum? Since the magnetron
is coupled to the waveguide from a probe in one of its cavities, I
would think that the higher sidebands would be significantly reduced.
Possibly you have made measurements on such a system.

The math, at least, does indicate the potential of building a very
wide band jammer -- probably not a good idea!

73,

Frank