Unreal Interference

[Clifford Powell]

In a park I ran across the strangest interference ever for me. In parts I could run at manual sensitivity of 20 and then I would hit ground that the chatter was so intense that I could hardly pick out the sound of a clad quarter on the surface. No help from noise cancel. Tried turning the sensitivity clear down to 4 and the machine was sill going crazy. If I got out of IM it reduced the chatter just a little but the null became almost continuous. Move 20 feet and back to normal. There were pockets of this interference all over the park. No power lines in sight but I noticed there were flood lights without wires running to them so they had to be underground. So I tried to hunt next to the light standards - no problem. Very strange.

I still did OK by just skipping the bad pockets. Anyone ever run across this? Just curious.

Cliff - - -

 

[Chris(SoCenWI)]

n/t

 

[Steve(MS)]

If you have a smaller coil, you may be able to get in that area and detect it.

 

[PULLTABBY]

I have encountered this twice in my 20 years of hunting where the detector just goes buzzerk and won't calm down in that area at all.
Freq change did not help or noise cancel ??? I had to move on and never did figure it out. One was in a field where there obviously were no under ground wires....
My first thought was maybe a near ground "ORE" vain or some type of heavily mineralized ground.

 

[Cody]

I have ran into a few sites with this problem. What I found is "clinkers" were dumped at the site. When coal is burned in a stove clinkers remain and are dumped something like dumping ashes from a wood stove. The clinkers respond like very hot minerals so we end up with the detector not being able to ground balance properly. The results are as you describe. I sometimes find this condition in the yard so old home sites where clinkers have been dumped. I think they were used to melt the snow and ice or prevent slipping. Anyhow that may be the problem. Also when fill dirt is used at a site if the minerals are very different from the native minerals at the site then we have a very similar problem. Bricks dumped or underground will sometimes cause this. We can tell to some extent when we dig in the soil that there is a lot of fill dirt so when I see this and have that experience I am fairly sure one of the above is causing the problem.

 

[WThesing]

I had a situation a few weeks back that still remains unsolved. I have exculsive permission to hunt a 700 acre private land trust that has a lot of Revolutonary War and Colonial history. I've been occasionally working bits and pieces of this site for over a year. At the edges of the tract there are a number of fully restored colonial homes, some of which I also have permission to hunt. I went to one of these properties a few weeks back on a Sunday afternoon. Started working and after 5 minutes My Explorer II went nuts!. It would not stop chattering no matter what I did until I dropped the sens. to 4 or disconnected the coil. I thought at 1st that maybe the problem was in the X-1 switch - not so. I switched over to a Sunray X-5, NO Change. If I were to get the non stop chatter to stop after reset, coil unplug, etc., it would start all over again within a minute or two. I finally gave up thinking that my machine was going back to Minelab. When I got home (3 miles) I turned the detector back on - ALL FUNCTIONS NORMAL. The machine has behaved as normal since. My theory is that there may have been strong radio transmission in the area at the time. There are no power lines. It is possible that one of the homes may have a HAM radio ( hard to tell because of woods) OR there is a large cathedral within a mile that has a bell tower between 12 & 15 stories high. Maybe the cluster of lightning arrestors contains an antenna. The particular cathedral is also the world headquarters for a very small religious denomination, and perhaps they may have been transmitting at the time. I have not been back since due to time limitations but my machine has been flawless since. Never had this happen before.