gumbeaux, beginners coming on forums confused about "disappearing signals" is a common theme. And in each case, there's always an easy explanation. HOWEVER, it's impossible for anyone to diagnose over printed text, as to what you are doing wrong. Because it's always one of those type things where we'd have to be there, to see what you're doing, what you're hearing, how you're trying to retrieve, how your machine is set up, etc... Things like when someone says " .... and I get a signal...", when you think of it, is arbitrary. Because who's to say they're not getting confused by non-repeating flutters? Or hearing the occasional beeps from their steel toes boots? etc...
Example (and promise you won't get "lost in the example"):
One time there was a beginner in my area, who got his first machine, an XLT, from an on-line order. He'd never detected with any other persons before, but figured he could read the instructions, and that should tell him how to operate it afterall, right? So he heads out to a local campground, and finds a few shallow clad in his maiden trip. Ok, so far so good. However, a host of other signals keep "disappearing" Huh? He reads the entire instruction book several times, to make sure he's doing everything as-per-spec. So he sent the machine back to the whites factor for repair. They sent it back saying it's checked over good. So he goes back out, and it does the SAME THING. So AGAIN he sent it back to the factory for "repairs".
And again Whites sent it back to him saying it works fine, and they could find nothing wrong with it. He began to get so upset that he called Whites West coast distributors to complain about their lousy machine. He was eventually put through to Jimmy Sierra himself, who listened as the fellow described the problem of "disappearing signals". Jimmy says "you're operating it wrong somehow". When the md'r heard this, he was sort of insulted, as if he was a dummy, incapable of reading instructions, and/or using common sense. I mean, how frickin' difficult can it be? He had read the manual through several times by then!
At about this time, he got on forums, and discovered that there were other hobbyists in his area, including myself. He asked me if we could meet up, so I could help him figure out what's wrong with his machine. I agreed, and we met up. Within 2 minutes I immediately diagnosed his problem: Each time he'd get a signal, he'd "slow down" to hear better. BUT WAIT, this is a MOTION discriminator (and xlt is a fairly fast motion mind you). So guess what? When he'd slow down to hear better, doh, it would "disappear".
When I pointed this out to him, I asked him: Didn't you read the instruction manual where it said "motion required" ? He said yes, he'd read that of the manual. However he figured that just meant you needed the coil to be swung side to side as you detect. And when he had read that, he thought to himself:
"gee that's a silly instruction. I mean, duh, HOW ELSE is someone supposed to progress through the field, unless they are swinging their coil? I mean, duh, do they really think someone's gonna stand their with their coil motion-less on the ground, and expect to get any detecting done?"
Do you see that no amount of printed instructions can fully convey an instruction like that? Same for things like "sounds". There are some things that have to be seen and heard, and no amount of printed instructions/text are going to fully be able to convey.
So your best bet is to hook up with someone proficient in your area. Go out, flag signals, compare. See what he's hearing, how he's digging, what he chases vs. what he passes, and so forth. Pick a zone with prolific easy clad, not some hard-pounded relicky site where signals would be few-&-far between.
