Interference that can't be noise cancelled?

[brissietex]

Hi all...

I was out detecting early this morning on the beach and all was going good until all of a sudden my Exp II went all haywire (almost like a switch was thrown) with a constant the warble of falsing from some interference which I at first suspected to be from either proximity security systems or something else unbeknownst to me. I was still able to continue detecting but the falsing was driving me crazy since turning down the sensitivity did little to quiet down the machine. Has anyone experience something like this? I don't think it is the machine but I can't be 100% sure. Has anyone experience their machine begin constantly falsing after an hour or so worth of use? I am trying to figure out if I need toe get a tune up on my Exp II.

I am using an Exp II with a 15" WOT coil. The beach is usually pretty stable with very little black sand and was mid tide (between low and high). The falsing was all over the beach (dry and wet) even where I had already detected without any prior interference.

thanks in advance...Keith

 

[BlackX]

n/t

 

[mattockman]

It could also be a loose connection from coil to housing...recheck tightness....and weak batteries may not be good....noise cancel.....and recheck plastic nut on coil wire at the coil, it should be finger tight....not with a wrench.

 

[brissietex]

Yeah...I need to check the nut on the coil. I thought I checked that before I went out this morning but I'll confirm it. The coil appeared to be rock solid up to this point so may be it loosened up somehow.

I've had the same interference without a coil cover on...started going without a cover for a while (just in case). I usually don't use one but was too lazy to take it off this morning. I rinsed the coil when I started to get the interference but didn't make much difference but then again the rinsing may not have gotten all of the sand out.

I also had a thought that maybe water or sand got into the coil via where the coil meets the wire. No way to really confirm this though other than to change out coils. May need to seal this connection with an epoxy.

thanks...Keith

 

[SNOWY]

Kieth I hope you haven't got a water leak where the coil lead goes into the coil, as this will be very bad !
Especially if salt water gets int the wiring, it causes havoc !

When you get a Wot delivered from Coil Tek in a cardboard box, the plastic nut with the cable strain relief
is loose, ( right off the threaded section next to the coil body,) before you use the coil you are to nip it up
pretty tight to compress the "O" ring gland to make it water tight...
If this nut/strain relief is loosened off by anyone at a later date, and re-tightened you can sometimes lose the
sealing integrity; and water can make its way into the coil body.

I have had trouble in the past with bad electrical connection from the batteries of detectors.
I have found that moistening some tissue, or rag with CRC, or RP7, and giving the battery contacts a rub can
improve things... Don't spray directly onto the Explorer battery packs though !

Do you get the same problem using the stock coil ???

 

[brissietex]

Okay, I recharged the battery pack, took off the coil cover, tighten the coil nut and away I went to the beach (different one to the day before)...

Well, my ExpII with the WOT coil was stable as with very little falsing in the wet and dry sand. Never went near the water and don't think got the coil wet at all. Brushed off the sand every now and then. An hour or so after detecting, the machine went nuts all of a sudden like before in both the dry and sand tho I will admit that it was less in the dry. I noticed that the time was close to 7am. Some ppl and lifesavers around and I was a fair distance from the slsc but that is it...bugger if I know...

Tomorrow I am going to try the alkaline battery pack(2500 nimh) instead of the rechargeable one. Perhaps the rechargeable one is losing its charge too quickly. I will pack my XT-70 also just in case.

cheers...Keith

 

[Fishhead]

Change back to your 10 inch coil to eliminate the possible WOT problem.

 

[digitrich]

But it's more of a rhythmic pulse. Every 1/2 second or so, I would get a false signal, never in the same place on the smart find screen, so at first it seemed like the machine was going bonkers. Try a smaller coil, lower your gain, and/or sensitivity, clean your coil cover out, if it's electrical interference you should be able to hold your coil off the ground and still have it happen. Try to manually pick the noise channel with the least interference. With the electric fence, nothing helped what so ever except turning off the fence.