Re: High voltage standing waves with a magnetron?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "mercurus2000" <mercurus2000-at-cox-dot-net> 

Yes, but I'm looking for the high voltage output, which is why I wanted to
try to drastically underpower the magnetron, I was hoping to get the high
voltage field without the extreme heating effects. Are you sure I can't
underpower it in any way?
Thanks,
Adam

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Saturday, January 31, 2004 4:57 PM
Subject: Re: High voltage standing waves with a magnetron?


 > Original poster: "Jim Lux" <jimlux-at-earthlink-dot-net>
 >
 > What you're describing is a fairly standard operation.. you're talking
about
 > using a microwave oven magnetron to excite a resonant cavity of some sort.
 > It's a bit trickier than just coupling it in, because as the cavity power
 > goes up, power starts to flow back to the magnetron.  What you'd really
want
 > is called a "resonant ring", which is something we use for high power
 > breakdown testing.  Conceptually very simple, it's hard to get to work: as
 > it heats up (and it does), the phase shifts change, so you have to keep
 > adjusting it to keep it working.
 > The trick is getting small power out of a magnetron. You can't just limit
 > the current and keep the voltage constant (because that's not the way
tubes
 > work).  And, there's a certain threshold below which the magnetron won't
 > oscillate.
 >
 > If you want to fool with microwave at low powers, there's a couple
 > inexpensive and easy ways.
 > #1... use one of those 2.4 GHz wireless TV thingies.  You can improvise a
 > probe with a suitable diode and antenna.  You can enjoy all the nifty
stuff
 > fooling with a slotted line.  The problem is that 2.4 GHz is 12cm, so the
 > waveguide is big!
 >
 > #2.. scrounge up a 10 or 24 GHz source as in a doppler door opener or
 > burglar alarm.  Then the wavelength is a more reasonable 1-3 cm.  You can
 > easily fabricate cavities and such with coffee cans, pipe, etc.
 > http://home.earthlink-dot-net/~w6rmk/radar10g.htm has some info on what I did
 > with one. (if the links are broken, let me know... I'm in the midst of
 > rearranging all my websites)
 >
 > #3 look around for surplus microwave gear... it's there, and often quite
 > inexpensive.  Very few people are willing to make measurements with
slotted
 > lines and sweepers anymore, since vector network analyzers make life so
much
 > easier.
 >
 > If you drop a bit lower in frequency (say, to 144 MHz), then you can build
 > open wire line out of copper pipe and such, and it's easy to come by
sources
 > of several watts to 50Watts.
 >
 >
 > ----- Original Message -----
 > From: "Tesla list" <tesla-at-pupman-dot-com>
 > To: <tesla-at-pupman-dot-com>
 > Sent: Saturday, January 31, 2004 10:27 AM
 > Subject: High voltage standing waves with a magnetron?
 >
 >
 >  > Original poster: "mercurus2000" <mercurus2000-at-cox-dot-net>
 >  >
 >  > I was just curious if anyone experimented with high voltage standing
waves
 >  > from a magnetron and trying to create a resonant rise from them? My
idea
 >  > for a safe experiment, would be taking a small microwave oven
magnetron,
 >  > power the filament at that standard 3 volts ac or dc, and applying
 >  > EXTREMELY small power HV DC current to the entire device, like 4000
volts
 >  > at a half a milliamp, to keep the power output at about 2 watts rather
 > than
 >  > the normal 1KW, would a circuit like this work? Or would the heating
 >  > current to the filament have to be reduced as well?
 >  >
 >  >
 >
 >