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Magnetron use

  1. Jul 8, 2010 #1

    I want to do a test heating a hot dog in a tube using a Magnetron from a 900W Microwave oven. Before doing the test I would like to know if there is any reasons not to mount the magnetron antenna on top of the metal tube, or on the side. (Please see attached picture)

    Also, will I need a rotating reflector to distribute the waves?

    I am not shure this is the correct forum. If not, please advise the corect one.


    Attached Files:

  2. jcsd
  3. Jul 9, 2010 #2


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    Staff: Mentor

    Welcome to the PF. What does your overall shielded enclosure look like?
  4. Jul 9, 2010 #3
    The tube is approx. 23cm long, with a diameter of 7cm.
  5. Jul 9, 2010 #4


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    Staff: Mentor

    That's not exactly what I was asking. I was asking what your RF shielding strategy is for the overall device. What experience do you have in the area of high-power RF shielding and testing?
  6. Jul 9, 2010 #5
    Some of the questions you ask make me wonder if you should be playing with a magnetron or the 4000Vdc, 500mA+ power supply
  7. Jul 9, 2010 #6
    Good observation…. Yes, I have no experience regarding using Magnetrons or shielding waves from a Magnetron. However, I worked with RF transmitters in the military, repaired BW and Color TVs, and are presently working with 600VAC, 300Amp circuits, so I think I know what I am up against, and that is why I found this forum to educate myself, before I hurt myself or anyone else.

    The metal tube I am using will not have any holes as in a microwave door, so waves should not escape the tube. To prevent overheating I will install the thermo sensor from the microwave oven

    Are there any other concerns I should consider? Any help will be greatly appreciated.

  8. Jul 11, 2010 #7
    I think I see what you're attempting, but at best I don't think it would give the desired result.
    First, the tube needs to reach a medium where the wave can propagate. Judging the tube from the size of the hot dog, your space is too confined to propagate a typical microwave oven signal (2.? GHz)
    The next issue is that you're coupling REALLY well into the hot dog near the point of insertion. That means your energy is gonna to heat the hot dog very quickly near the antenna and hardly at all as you move away.

    Personally, I'm creeped out by these high powered microwave projects. A little RF leakage can injure you in the bone before you notice. Also, and not to be shunned, the power supplies on these will kill. I worked on TV's in college and developed offline motor drives and power supplies. None of that stuff is near as deadly as these microwave projects.

    If you want to make the hot dog cooker of the age, I'd stick with something a little safer, like a Pyrex tube with heater wire and insulation, or maybe a stainless steel tube with induction heat, or a hot air design. These all have hot surfaces, so they can injury you, but you'll most likely come away with life and limb. That's a guarantee you won't get with high powered RF.

    Best Wishes,

  9. Jul 12, 2010 #8
    Thanks for the response and the warning. However, I have to figure out how to do it.

    Induction heat or hot air does not work, since the hot dog being heated is in a plastic pouch.

    To propagate the microwave signal I might be able to increase the chamber to 25cm long, 7cm wide and 25cm high, so the antenna is about 20cm above the hot dog. Will that work?

    Can anyone direct me to where I can learn about microwave oven design?

  10. Jul 12, 2010 #9


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    Staff: Mentor

    Just googling microwave oven design gives you this hit list:


    I'm afraid that I need to close this thread. We can't be giving much more support on this via an Internet forum. Hopefully you can find a mentor or consultant in your area who can assist you with the design, and with the FCC and UL submittals.
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