EMI on metal detectors

Rammjäger

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Hello from an old forum member in Germany;
I have a question about emi interference on my metal detector. I had recently quit metal detecting a spot after my detector went wild making strange sounds, later I realized there were these huge power towers which caused the problem. I would like to try wrapping the control box with aluminium paper/ alufolie and see if the interference stops. Some kind of Faraday cage if possible. Has someone tried this ?
Any answers are welcome ! Thanks
 
I tried totally wrapping the control box with aluminum foil during a bad EMI time here at home. It didn't help at all.
 
The coil is detecting the emi.
The coil cannot be wrapped in aluminum foil because it will not function.
 
I tried totally wrapping the control box with aluminum foil during a bad EMI time here at home. It didn't help at all.

Thank you for your idea. This detector that I have here now is low in frecuency .I had my Tesoro Cibola which was better rejecting Emi but I left it at my daughter's house in England .
 
Curious what detector and coil you are using.

When I worked at Compass Electronics they tried to shield one model using copper plates or a copper-type of foil. It kind of worked but overall didn't handle really bad EMI. Simple fact, a really bad EMI source is just that, a really bad source.

Some high-power sources are only periodic and once I figured out when they were not causing a problem is when I hunted near them. Other sources, typically high-power transmission lines, can be a full-time cause for EMI.

When i confront those isues I often do two things. One is to use a smaller-size search coil, which I typically do anyway. And the second thing I do is select a different detector in my outfit that suffers the least from the particular EMI source. It isn't only the control housing that causes the EMI but also the search coil and even the coil cable to the control housing.

Monte
 
Only chance left , is for me to walk away from the tower''s out of reach and many meters as possible and see if the effect decreases...
 
Curious what detector and coil you are using.

When I worked at Compass Electronics they tried to shield one model using copper plates or a copper-type of foil. It kind of worked but overall didn't handle really bad EMI. Simple fact, a really bad EMI source is just that, a really bad source.

Some high-power sources are only periodic and once I figured out when they were not causing a problem is when I hunted near them. Other sources, typically high-power transmission lines, can be a full-time cause for EMI.

When i confront those isues I often do two things. One is to use a smaller-size search coil, which I typically do anyway. And the second thing I do is select a different detector in my outfit that suffers the least from the particular EMI source. It isn't only the control housing that causes the EMI but also the search coil and even the coil cable to the control housing.

Monte

Hello Monte,
This detector is a cheap one .I guess some 8 or 9 Khrz.
frecuency. Compared with my Tesoro Cibola which is some 17 Khrz high is a huge difference. I remember years ago detecting near power towers with my Tesoro and not having any interference at all.
 
Rammjäger: said:
Only chance left , is for me to walk away from the tower''s out of reach and many meters as possible and see if the effect decreases...
Sometimes that's all w can do.

A while ago I lived in a big metro area and there were several parks in a series that followed 3 big transmission lines, and were directly under them.. I talked to people who couldn't hunt the Tot-Lots or the grassy parks due to EMI.

So, I figured I would take on that challenge with my detector outfit I used at the time. White's MXT Pro and XLT, Teknetic's T2 and a couple of others, didn't handle it. My Tesoro Bandido II µMAX and modified White's IDX Pro could do reasonably well. But the better performer was my BBS Sovereign Xs2a Pro.

Not only did they work, with a little interference, so I reduced the Sensitivity, and I really cleaned house in those Tot-Lot playgrounds. I spent four days of several hours each day hunting them and I recovered a LOT of coins and several pieces of jewelry, some of which was not costume.

In the end we either need to select the best detector and coil to handle the conditions, or simply walk away from it, if it is a full-time problem source.

Monte
 
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I have a lot of electrical power line transformer caused EMI with the Equinox in the older part of the city I live in. I have made some good finds while wrestling with EMI. The Nokta Impact I had seemed to be affected pretty bad by EMI. The only detector I have used that never had a chatter problem around EMI was the Etrac.

As mentioned lowering sensitivity and going to a smaller coil can help. I wonder if all these 5g antennas are going to complicate EMI issues. I have not hunted close to one yet. They are putting them up everywhere though.
 
I have a lot of electrical power line transformer caused EMI with the Equinox in the older part of the city I live in. I have made some good finds while wrestling with EMI. The Nokta Impact I had seemed to be affected pretty bad by EMI. The only detector I have used that never had a chatter problem around EMI was the Etrac.

As mentioned lowering sensitivity and going to a smaller coil can help. I wonder if all these 5g antennas are going to complicate EMI issues. I have not hunted close to one yet. They are putting them up everywhere though.

The 5G introduction makes me wonder also, and my Etrac never gave me a hassle either.
 
I went to the same spot .
No EMI interference today .I just walked some feet
away from the power lines .After one hour with
no target signals, suddenly one good signal . There
were green coins on surface, just under the leaves!
First I thought it was a coinspill , but then got 67 Eurocoins of 2 and 5 Cent each .After cleaning them , aged between 2002 to 2010. Somebody dumped them there some 10 years ago.Lol.
 
I've had this problem and detected in pinpointer mode to get around it. This worked somewhat but it was quite annoying as it was constantly getting detuned. I was using an E-Trac

This was a small area directly under power lines. I would not recommend trying this on a larger area as it is a hard way to go about things.
 
Hello from an old forum member in Germany;
I have a question about emi interference on my metal detector. I had recently quit metal detecting a spot after my detector went wild making strange sounds, later I realized there were these huge power towers which caused the problem. I would like to try wrapping the control box with aluminium paper/ alufolie and see if the interference stops. Some kind of Faraday cage if possible. Has someone tried this ?
Any answers are welcome ! Thanks

I have never found a fix. Unfortunately, sometimes you just can't hurt certain places. There's an old school in my hometown that is like that. No matter what Detector I take they go nuts.

Never have figured out what's causing it.
 
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