Weird Tejon EMI Issue

[kittlitz]

Our club hunted a large park area yesterday, and I could not get my Tejon to settle down. The behavior was the same as I experienced in certain parts of the beach when hunting in Hawaii, but this time I couldn't find an area where it wouldn't happen. The symptoms are as follows:

o Machine was very chattery, especially during the normal swing motion but even when it was held still.
o The threshold would not go silent, even at the minimum (fully counter-clockwise) position. At most, the tone pitch would lower frequency a bit.
o Reducing sensitivity to minimum made no difference.
o Primary discrimination was set to about Foil.
o If I held the machine out straight in front of me, so that the shaft was parallel to ground, the chatter stopped.
o I was using the 8" concentric coil; whereas in Hawaii I'd been using the 8x11" RSD. So the problem doesn't appear to be coil-dependent.

Needless to say, this was a frustrating hunt. With the threshold not behaving correctly, I couldn't really ground balance.

I tried the machine in the backyard when I got home, and it was fine; threshold behaved normally, very little chatter, etc. So the problem seems at least partly environmental. The only (weak) theory I have is that there was a very tall transmission tower about a mile away from the park but.. that seems like a longshot. As far as i know, no one else in the club had similar issues. I'm not sure how many Tesoros were being used, but at least one guy had a DeLeon and had no EMI problems.

If anyone has experienced something similar, or has an idea what's going on, please let me know.

Thanks,

-Ken

 

[nagant]

would it be under ground transmission lines? Maybe wiring for lighting. Could be a ground balance issue, if they landscaped and used fill hard telling if it all came from the same place.

 

[Stoof-tabsallday]

Was the threshold "wobbling" when you were having the issue?

 

[kittlitz]

Hi guys, thanks for the replies!

The park was a large area on a hillside by the river valley. I moved around a lot but couldn't get rid of the issue, so I don't think it could all be due to underground wiring but.. who knows.

The threshold tone didn't wobble at all, it made a sort of moaning sound instead. If I turned it fully to minimum, the pitch of the tone would drop and sometimes it went silent for a second or two, but then it it would start moaning again.

The club is having a hunt at another park tomorrow, so I'll see how the Tejon does there. Going to bring my Mojave as a backup.

 

[nagant]

Good luck and let us know how it go's.

 

[kittlitz]

The Tejon was rock solid at this other park yesterday; no chatter and the threshold behaved normally. There must have been something specific to the first park that gave it grief. I plan to go back there at some point to see if the problem re-occurs, and will bring a couple of other detectors to see how they do. Will post an update here when I do.

 

[hooelo]

You said it was a club hunt is it possible another detector or detectors running the same freq. was interfering? I owned a euro saber that would drive other tesoros nuts.

 

[kittlitz]

That's what I thought it was at first, but the problem persisted even when I was 100 feet or more away from any other detector. At yesterday's hunt, I did get some interference when I got a few feet away from a Minelab 305, but that was about it. I was able to get the same distance to my friend's CTX 3030 without either of us having problems. So my best theory is that there was just something weird about the first park

 

[hatpin]

My Vaquero acts like that when there are cinders in the ground . The dang thing wont shut up no matter what I do .

 

[nagant]

OK I've done this myself Coil connector wasn't tight and had all kinds of weird chatter.

 

[Oldguy]

Turn on your pinpointer in the air, and then move it to the ground, if the problem is truly EMI, such as underground power or pet containment systems, the pinpointer will act up too. If the pinpointer operates normally but the detector still still acts up, it's probably something with the detector.

 

[kittlitz]

Turn on your pinpointer in the air, and then move it to the ground, if the problem is truly EMI, such as underground power or pet containment systems, the pinpointer will act up too. If the pinpointer operates normally but the detector still still acts up, it's probably something with the detector.

Thanks, Oldguy, that's a good tip. I'll try it when I return to that park. The Tejon has been totally stable at other places since then, so I'm thinking it has to be something in that specific location.

-Ken