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Recent content by ProfK

  1. ProfK

    dangerous plasma generation?

    Well guys; I tried it. Nuked a vacuum pumped quartz flask. Yes, a very nice purple plasma filled the flask. The plasma stopped at the neck where the smaller tube was fitted and where the vacuum was pullled from. After 30 seconds, the flask was hot to the touch and clearly heated by the plasma...
  2. ProfK

    temp sensors in microwave ovens

    Excellent work. It supports my observations too. But it doesn't answer how one can make a metal sheathed probe to measure temperature inside the cavity in many of the older high-end microwave ovens and still have it register a proper temeprature? Could it be the probe tip was at meat...
  3. ProfK

    dangerous plasma generation?

    Yes, Comcokid, ionized gas is called a plasma. Some consider plasma a fourth state of matter. Anyway, considering those plasma balls are sealed, I suppose a conversion of the evacuated sphere gas to plasma shouldn't pose a threat. It's just that I have seen a vacuum chamber of metal pumped...
  4. ProfK

    temp sensors in microwave ovens

    How do the microwave oven manufacturers allow a metal (stainless?) probe to function properly as a temperature sensor? When I experimented by putting thermocouples or metal tubing inside the cabinet through the vent holes, they get quite hot even though I ground them well to the cabinet. There...
  5. ProfK

    dangerous plasma generation?

    Hypothetical (before I do it for real)>>> Setup: Take a glass bulb 4 inches in diameter with a glass tube in one side to attach a vacuum pump. Pump a (roughing quality) vacuum through the glass tube inside a 1kw operating microwave oven cavity. As the air is removed and a certain vacuum level...
  6. ProfK

    is there a best place to drill into a microwave oven?

    Thanks H. I gathered as much when you suggested it. I thought maybe there was more to it. Regarding video sender, I get interference on mine when uwave is on too, but it would be hard to use that as a measure of signal strength.
  7. ProfK

    is there a best place to drill into a microwave oven?

    Gas in volcano... SO2 Purpose is to use uwaves to extract water from soil on an unspecified unearthly body. Need vacuum and cryogenic temperatures to approximate the environment. BTW, how might one employ a cell phone to find leaks? All I found was a claim that if one was put inside a closed...
  8. ProfK

    Temperature measurement inside a microwave

    Sorry, bad grammar. Regarding depths, I meant that temperature measurements at multiple depths were the goal. I envisioned 2-4 thermocouples with metal sheaths inserted in the material and not having any interference between them nor at the readouts with the microwaves on. The sheaths would be...
  9. ProfK

    is there a best place to drill into a microwave oven?

    Thanks Higgler, some of the comments are very worthwhile. The heating need is to saturate a low loss material (powdered rocks) with the full output of the magnetron while pumping to a vacuum pump; hence the tubing. So, no, water liquid or other lossy material will not be passed through the wall...
  10. ProfK

    is there a best place to drill into a microwave oven?

    I wish to insert ~1/2 inch OD glass and/or plastic tubing through a commercial microwave oven cabinet wall. The question is, might there be a particulaly safe location to do drill? I refer possibly to the corners of the cavity, a mathematically calculated position like 1/2 wavelength in from an...
  11. ProfK

    Temperature measurement inside a microwave

    I too need temperature monitoring inside a microwave cavity (oven) and have considered the Luxtron. I also need multiple depths to be monitored at the same time. What about using stainless steel shielded thermocouples where the shield (only) is grounded to the cabinet? The probe diameter can be...
  12. ProfK

    can old oven magnetron be powered by stepper supply?

    Question in subject. I can get 1-2kW stepper supplies for industrial magnetrons on ebay. With custom, do it yourself hook-up, can the $100 oven magnetron be run from one of these? The purpose is to operate variable power levels and not use duty cycle for temperature control. Is there some...
  13. ProfK

    How can one build a microwave laser?

    Thanks higgler and biff44. Sorry to steal thread.
  14. ProfK

    How can one build a microwave laser?

    Higgler, you have said about three times that you focussed microwaves in this forum. Where is the work or anything like it documented? I wish to do similar things with 2.54. I also can't afford $300K for a gyrotron, but need to experiment.
  15. ProfK

    How can one build a microwave laser?

    What you want is called a gyrotron. The high frequency of operation ~100GHz allows focusing of a microwave beam to a spot near the diffraction limit which is about the wavelength.
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