Microwave oven temperature probe port grounding

Just wondering what would happen if a metal container was used in a microwave, but grounded to the phono jack for the temperature probe. Assuming the connection was good, of course.

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Tom Del Rosso
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"Tom Del Rosso" wrote in news:mv80i.43$yM2.8 @bgtnsc04-news.ops.worldnet.att.net:

The 'grounding' would not help.

A 'good ground' at microwave frequencies would be much less than 1/4 wave. The wavelength is about 3 cm.

A good ground would thus need to be much less than 1/2 cm.

A metal container is probably going to arc to the inside of the oven in several places.

It may detune the cavity badly enough to present a high SWR to the magnetron and damage or destroy the magnetron.

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bz

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bz

The wavelength is too short for any effective grounding, and that is a 1/4" Phone jack, not a phono jack.

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Michael A. Terrell

Very interesting. I thought the wavelength was a few inches.

So how does the probe get away with it?

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Tom Del Rosso

He meant to say 1/4 wavelength is around 3 cm. :) The wavelength is a few inches, like around 5 inches.

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Reply to
Sam Goldwasser

Sam Goldwasser wrote in news: snipped-for-privacy@red.seas.upenn.edu:

Actually, I was thinking x-band radar was very close to the microwave oven frequency. I was wrong.

The X band ranges from 7 to 12.5 GHz. The microwave ovens actually operate in the S band, the 10 cm radar band. The S band covers from 2 to 4 GHz.

According to

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most microwave ovens operate on 2.45 GHz which gives 11.8 cm wavelength, 4.6 inches, for a quarter wave of a little over one inch or 2.95 cm

In any case, it is still a bad idea to put any metal bowls into your microwave over, unless the metal object has been designed for use in a microwave oven.

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bz

Ok, but the probe is over 6 inches long without the plug, so why doesn't it collect a charge? I always assumed it was because of the grounded plug.

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