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Author Topic: Suggestion on a cheap EMI detector  (Read 3073 times)
AA4HA
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Posts: 1377




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« on: April 15, 2010, 05:51:14 AM »

A few years ago (ok, a long time ago) I had an idea to make an EMI/RFI detector for portable use. What I lit upon was to take the head out of an old tape-deck and feed the output into a very high gain op-amp circuit and then run that output to a earphone. The entire device was smaller than an Altoids tin and was powered off of a 9 volt battery.

When doing an EMI/RFI sweep of a building the tape head is very sensitive when placed in close proximity to the offending device. I could even put the tape head sensor near the breaker handle in a circuit box to find individual branch circuits where an offending device was attached to.

At one time the biggest source of RFI in a home was the television set. Now it is pretty much anything with a digital circuit and a circuit component that oscillates.

Just a tip,
Tisha Hayes, AA4HA
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Ms. Tisha Hayes, AA4HA
Lookout Mountain, Alabama
KF5CZG
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Posts: 89




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« Reply #1 on: April 15, 2010, 05:56:31 PM »

Cool.  Sounds like a great sniffer.
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