Interferrence ???

[JimGilmore]

I was hunting a local high school and found i could not really use my tesoro golden as I was planning to.
I was able to use my Fisher goldbug pro with some difficulty. It did chatter and chirp for no apparent reasons though.
I'm wondering if anybody else has encountered such problems and what unit you go to to work such locations.
This site has aone of the moving electric signs that schoools use to display messages on the side of the school. and i think that is a part of the problem. Either they did not put the lines deep enough or it is bleeding into the surrounding soil in some way.

 

[Dave J.]

http://www.fisherlab.com/Hobby/davejohnson/Electrical%20Interference.htm

 

[MarkCZ]

Thanks Dave for the link!

Mark

 

[markg]

Very helpful information. I too found the Gold Bug Pro the most stable unit I've ever used, it way surpasses the stability of the F75.

 

[GeorgeinSC]

I have found that a smaller coil is useful when there is a lot of EMI. There is one park that I have detected that has large High Voltage lines that pass over the park. I used a small coil and even though I had to cut sensitivity a bit was able to detect that park. Found a couple sterling rings and quite a bit of clad.

 

[bootyhoundpa]

If they have underground wiring I would avoid the general area in fear of accidentally digging into a live wire..

 

[Ism]

Jim, I have a Vaquero and it's the most stable detector of the few I've used around EMI. I use the DD coils though, may help?

 

[ironsight]

Also happens occasionally with my eTRAC sometimes in the middle of a field with no visible EMI sources in sight.

As GeorgeinSC said, try a smaller coil. The coil can be considered a radio antenna. The larger the coil, the larger the antenna.
If the detector has the option, try shifting or changing the transmit frequency. The eTRAC's noise setting and also my ATPro can do this.
Lowering the sensitivity setting is the best option.
Sometimes hunting in a different direction might help.
Using a tight discrimination pattern can help a little.

And then sometimes nothing helps in heavy EMI areas