Why? Because there are just so many variables involved, especially with the offerings we have today. Times have changed.
It used to be we had a simple metal detector, such as a BFO or TR design. We turned it on, tuned it as best we could for a best-suited motor-boating beat (BFO), or a slight audio Threshold hum (TR), and worked the coil over the ground (while maintaining a proper coil-to-ground position). If we got a beep, we simply pinpointed and recovered the target.
In those earlier days of detecting, for me from about March of '65, and with most of the folks who have been at this for quite a while from about that period to the very early 1970's, we found interest in finding stuff. I detest the words "Treasure Hunting" and pardon my brief use of it here. Yes, like a lot of folks, it was a popular term used very early on, but while we all look for metal targets of interest to us, some politically-based groups (organizations or professionals, especially with a government connection) took offense to that term. They have associated it with looting and pilfering, lumped metal detecting enthusiasts, who are mainly urban coin hunters, as being vandals and part of it in my opinion is tied in to that wrongful TH-ing label.
Okay, so what we did was Coin Hunt, mostly. There were those who had the desire to seek out more out-of-the-way locations that might have been associated with the Civil War or a Stage Stop or an old Mining Camp, or all sorts of 'old places', and they wanted to find period objects from those types of locations. The different groups of detecting enthusiasts have sort of split the interest in detector design, too.
The avid Relic Hunters, and I refer to not just anyone seeking coins at an old place, but the dedicated searcher for any artifact at an older site was usually going to recover both ferrous and non-ferrous targets. If there was anything they wanted in the way of features and performance it would have been a lighter-weight and handier detector design to work in the woods and brush, ease of operation to better handle uneven ground or challenging mineralization, and ... of course ... better depth and sensitivity.
Most of us do not live in, or close to, most of the locations where serious Relic Hunting takes place, but we do live near beaches, parks, schools, picnic sites, recreation sites, parking strips, yards, and all sorts of urban locations where finding coins was of primary interest. Our early detectors worked okay, but when we started to encounter pull tabs some people wanted to not dig them. TR-Discriminating detectors were manufactured and they worked quite well. We listened to a Threshold audio, then ignored the rejected targets than ran the audio silent, or we simply recovered all targets that 'beeped.'
By the latter '70s and early '80s we might have had some of our best improvements in metal detector design. Coin Hunters also wanted a little better depth and ground handling, which was provided with the release of the VLF or BEB type metal detectors that canceled the ground mineral signal and let us get much better depth. These models mainly worked from about 2 kHz to 15 kHz at the time (VLF) and produced the depth. Then, to handle the problem trash we got the dual-mode models with a VLF or GB (ground balanced all metal mode) and a conventional TR-Discriminating mode to help classify trash.
That was a very popular time for metal detecting with a LOT of detector growth and sales, and people could frequently be seen out on any day, but especially weekends. Parks, schools, beaches, you name it, folks were out to enjoy the hobby. It was affordable and the detectors worked well.
How well? Ummm, have you ever noticed or heard a new comer complain that they are having a difficult time finding silver coins or any older coins, like Indian Head cents and Buffalo nickels? For those who got an early start in the hobby, learned their detector(s) and spent a lot of time out hunting, then they can tell you what happened to most of the coins that WERE out there.
Fast forward into the early-to-mid 1980's and on to the present. While we had the first motion-discriminating detectors available in '78 and for the next 5 years, many of us, including me, still did quite well with a good VLF/TR-Disc. model. Some transitioned to the new motion-based units and they were very fast-motion designs. Not until '82 when Fisher brought out the 1260-X and '83 when Tesoro gave us the Inca, did we experience good slower-sweep designs.
It was from about that time that we started to see more visual refinements in detector design, partly due to consumer demand. Coin Depth read-out, and that was followed with visual Target Id. Mainly Coin Target ID, and different approaches to let us tinker with our Discrimination levels, such as notch discrimination or the VDI numeric rejection on the Spectrums and since then. Detector prices started to soar, by comparison, about the time and more and more detector makers have tried to sell their product to consumers by adding features. Too many consumers have desired improved features to tell them that a target is, for sure, no doubt about it, really good so they won't dig junk.
Fat chance! It just doesn't happen.
We now have more powerful detectors and can get a bit better depth than we used to, and that is kind of good. But we have also inherited a lot of features that are expected to provide the right answer as to what is down there, and they simply can't. Not all the time, and especially when we move up to a larger-size search coil.
Bigger coils mightgain us a little better depth, but at the greater distance they have less strength in the EMF and it is a little more difficult for the electronics to process all the ground signal and target signal. Sometimes we just have to appreciate getting all we can for the site and expect to recover questionable 'iffy' signals. They are out there, more than ever, too!
Long ago we didn't deal with ketchup packets, taco sauce packets, Capri Sun juice packets, or the wide array of pry-tabs and pull-tabs. Screw caps were seldom encountered, unless you hunted around a bus depot, train depot, or other place where transient wine-o's hung out. Today, miscellaneous crap is everywhere. Yes, you can key-in on the most likely coin-type VDI's and recover a better percentage of coins, but don't expect success if you also want gold jewelry, or even silver jewelry or metal toys, bullets and other targets that can 'read' all over the place.
Just some thoughts, but I'd suggest just listening for a good hit, then recover it. Don't be too concerned about TID accuracy.
Monte
PS: On an XLT, MXT Pro, T2, Omega and a few others, I like to use Tone ID SOMETIMES, but not always. I only rely on Tone ID when hunting intentionally for the most likely-to-be coins that would be relatively shallow (4" or less) and in a sparse-trash site. Deeper, weaker, iffy targets can also fool you with some Tone ID use.
