Microwave Leakage Detector

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Microwave Leakage Detector

Post by jollyrgr » Thu Jul 17, 2003 6:27 pm

Does anyone have a schematic for a microwave leakage detector probe? I would like something that I could connect to my DMM and note any leaks. Radio Shack used to have one that used an analog meter and no batteries. I am assuming it would be simple to build using a diode, a couple of chokes, and capacitors. I assume a couple of short pieces of wire as antennas could be connected to the diode and the diode connected in parallel to a parallel tank circuit. Or possibly connect all three devices in series with the meter? Any ideas?
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Re: Microwave Leakage Detector

Post by Externet » Thu Jul 17, 2003 7:50 pm

Now you put me into digging mode in hundreds of old magazines.
Remember an article using a common op-amp with its straightened leads being trimmed as a dipole at 2450 MHz and not much else. I am not sure if a diode was piggy-backed between the leads... Will post findings,
- Abolish the deciBel ! -

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Re: Microwave Leakage Detector

Post by Chris Smith » Fri Jul 18, 2003 5:18 pm

Tiny neon bulbs light up around MW. Try attaching their leads to a AC volt meter, with or with out a op amp? The neon is the perfect absorber of this frequency, and the leads will generate the appropriate voltage, probably in the high voltage range? Neon bulbs usually take around 70 to 90 volts to light. Tiny current, but big voltage.

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Re: Microwave Leakage Detector

Post by L. Daniel Rosa » Sat Jul 19, 2003 1:03 pm

The simplest I've seen is a schottky diode in reverse-parallel with an LED. Solder the LED as close as psooible to the schottky. Trim the schottly leads to 1/4 wavelengths. The critical point is the Trr of the diode.

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Re: Microwave Leakage Detector

Post by rosborne » Sun Jul 20, 2003 4:36 pm

How strong is the EM source? Look up Branley Coherer. It was the first(?) EM wave detector in about 1890.

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Re: Microwave Leakage Detector

Post by tcsserv » Thu Jul 31, 2003 1:39 pm

An article in issue #35 June/July 1993 issue of Home Power magazine P. 72 "The Cantenna-- Microwave Oven Leakage Detector" --"Build a microwave detector in less than an hour with under $20 of Radio Shack parts", complete with schematic. The www.homepower.com website search has the index for the issue under HPindex, then page down for issue# search. Doesn't pull up the under keywords search though, maybe you can order a back issue of that #35 issue, or get it through interlibrary-loan and photocopy the article. A keyword search for microwave on the www.homepower.com search engine does pull up a good article w/schematic+partslist for a low cost, highly calibrated AC EMF detector.

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