Whenever someone comes on complaining of "disappearing signals", it's almost impossible for others to diagnose over printed text/internet. Because it involves "sound". And there is no feasible way to explain and describe sounds , in printed text. It would be like asking someone to "describe the sound of C major in printed text". It can't be done. You can only listen to it. Not read about it.
So too is it when the subject of disappearing signals comes up. There's signals vs mere flutters to be ignored. Or screen flickers to ignore vs solid repeating TID's. I have seen some amusing fixes and diagnosis come about to resolve the "disappearing signals", that are A) amusing, and B) could ONLY be diagnosed in person (not printed text).
Eg.: A beginner I took out for training, spent 10 minutes at the corner base wall of an old military barracks. Yet no matter how much he dug, the detector kept telling him deeper. Finally, he gave up in disgust and called me over. In 5 seconds I could immediately see the problem: He was hearing the flashing of the corner of the building (hidden under wood exterior), because he wasn't aware that the edge of his coil was also sensitive to metal (albeit it only an inch, but enough that he kept getting a perpetual signal, that he simply assumed was deeper and deeper).
Another beginner I was showing the ropes to, had complained of "disappearing signals", and sent his XLT into Whites two times to "get fixed". Finally, we figure out what his problem was: Each time he'd get a signal, he'd slow down to "hear it better". But since this was a motion machine (when in disc.), it would fade, the moment he'd slow his swing. Doh! I even asked him: "Hey, I thought you read the instruction manual 3x over. Then didn't you see the part where it said 'motion required' ? ". To which he acknowledged : Yes, he'd read that. But he assumed that meant to simply move the coil back and forth, as you're detecting. To which he thought "That's a silly instruction. I mean.... Duh ... how ELSE is someone supposed to ever progress through the field to hunt, if they're not swinging the coil. If the coil sits motionless, that's pretty stupid. You'd never get any detecting done".
So he simply didn't understand what that meant. And no amount of printed text can explain that fully. It has to be seen and heard and shown.
Thus my advice to the complaint of "disappearing signals" is to hook up with someone proficient in your area. Trade off flagged signals. See how he isolates , pinpoints, and retrieves.
