How to locate/identify EMI sources?

[bklein]

Is there an inexpensive means to identify EMI sources and frequency? Like one of the "paranormal ghost sensor" trifield units or whatever? Something comes on in my front yard that totally whacks out detectors - vlf or pi. The Edison people don't have a group that comes out to sense this. Not the streetlight. I have read others complain of certain buildings/houses that do this - how do we best pin down the sources?
I do have an HP spectrum analyser - I tried using it but could see anything obvious using a coil as sensor - I'd need to tie into the rx gain stage of a pi to get something meaningful. Just wondering if someone looked into cheaper and more portable solutions to find the sources.

[sinclairuser]

a frequency counter might tell you the frequency, or a radio scanner, it all depends what sort of emission it is, one of those magnetic detectors would see if its magnetic rather than radio related.

[bklein]

Sorry, I just found that I had asked this question here before - didn't catch it in my first topic search. Anyway, curious if someone may have tried one of the emi detectors. I can manually go through the CTX noise cancel channels and see big differences between them - but I don't know what the differences between them really mean/are. I guess I'll take the kit surf pi output and hook it to the spectrum analyzer. I cant seem to pinpoint the culprit with the ctx but now that I say this I didnt try pinpoint mode :-)

[rickb]

Try an am radio. harmonics from switching power supplies and other devices operated from line voltage can usually be heard all over the am band from 500 Khz and up.

[Skippy]

Loop antennae, like your search-coil, are directional when used vertically. They have two distinct nulls in pickup when the noise source is edge-on to the plane of the loop. So if you are able to rotate your coil until you detect a noise minima, you should be able to get some idea of the direction (or opposite direction) of the source.

[Funfinder]

> Is there an inexpensive means to identify EMI sources and frequency?

EMI yes but frequency not. However your MDs may react on fq from 5-100 kHz
as long as there are no special circuits which are sensitive to higher frequencies.
Your MDs itself may find the source if you set it to very low sensitivity and(or) without coils.

Some method to locate all kind of stronger EMI sources are FET or MOSFET opamp circuits.
Pretty simple to built and they can locate usual live electricity wires from 5m distance if not buried.

[bklein]

Tonite the Auto noise cancel of the CTX works pretty good. Not like earlier. Nothing unusual listening to an AM receiver.