What is this Microwave device?

Discussion in 'General Electronics Chat' started by Xray, Nov 21, 2004.

  1. Xray

    Thread Starter Well-Known Member

    Nov 21, 2004
    58
    1
    I recently purchased an educational kit of parts from an Ebay auction. The plastic carrying case is labled, "Electron Spin Spectrometer". Inside the case is a tunable waveguide, some microwave diodes, and a device that I can not identify. It is basically a chunk of aluminum with waveguide mounts on oposite sides, and thick glass windows at each waveguide slot. The device was made by Westinghouse, and the model number "WL-1Q22" is printed on the top aluminum dome. By viewing through the windows, I can see all the way through this device, and there is a copper post inside the chamber. Could someome please tell me what this device is? I have no documentation with these parts. I bought it to learn about microwaves and waveguides. Here is the link to the auction, so you can see photos of this misterious device. THANKS!

    http://cgi.ebay.com/ws/eBayISAPI.dll?ViewI...DME:B:EOAB:US:6
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Hi,

    Your mystery device about has to be a cavity magnetron. It's going to be vrey low power, but something has to generate high frequency rf to make the spectrometer work.

    At a guess, the waveguide stub is a tuneable dummy load. The rf connector it the output signal, which will indicate how much power the load is absorbing. The plastic thimbles will hold the materials being analysed. The output signal will be less at the point where the material resonates with the signal and uses some of the energy that would otherwise end up un the dummy load. The crank will let you do sort of a frequency scan, or else bring the whole apparatus back into resonance once a sample has been inserted.

    Maggies usually take fairly high voltages and currents - good luck getting it right if you pick this thing up.
     
  3. Xray

    Thread Starter Well-Known Member

    Nov 21, 2004
    58
    1
    Hi,
    Thanks for your reply! Well, that mystery device is definitly not a magnetron. There are no electrical terminals or wires on it. It is simply a chamber of some sort that was milled into a block of copper. The chamber (as I am calling it) has the two thick glass windows on each side of it. There is also a small copper tubing stub that has been pinched off, whcih tells me that the chamber has either been evacuated, or has been filled with a gas. I can look into the chamber through one of the glass windows, and I see only one little copper stud in the middle of it. I know this because I removed the copper block from the aluminum housing that has the waveguide mounting holes in it. The tunable waveguide is used as a Gunn Oscillator. That is what supplies the 10GHz microwave signal for the spectrometer. The little pellets that you mentioned are filled with a granular substance, and are labeled "MNO" (Manganese Oxide????). That could very well be the substance that this training setup uses for teaching about how an ESR spectrometer operates.

    Well, any other gueses as to what that mystery device is?

    Thanks again.
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Hi,

    With the Gunn oscillator in the arm, then the mystery device has to have some function as a resonant chamber. I was taking the copper stub as the output stub when I guessed it might be a magnetron.

    The whole device must be resonant at the Gunn frequency for the effect to be detectd. What is not clear is how the sample is inserted, and how the signal is taken off.

    After 24 years in the electronic shop at a major university, you'd think I would have seen everything, but this is the first electron spin mass spec for me.
     
  5. Xray

    Thread Starter Well-Known Member

    Nov 21, 2004
    58
    1
    There are some items missing from the kit. The protective foam in the large plastic box has some empty cutouts in it. It's very likely that the sample chamber and the RF detector are some of the missing components. The only major components that I have are the tunable waveguide (Gunn device) and that mystery device. I really bought this for the tunable waveguide. I wanted to learn about Gunn Oscillators by experimenting with one. I also have a microwave spectrum analyzer that I use to monitor the output of the Gunn so that I can see what effect different mechanical changes have on the frequency and amplitude. I do not NEED that mystery device, but I only want to know what it is because I do not know what it is!!!

    I am 57 years old and have been in electronics during all of my adult life. I too sometimes think that I've seen everything until something like this comes along!

    Thanks again.
     
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