makes and models that are of the so-called 2-filter design need to be operated at the best sweep speed for the conditions you're dealing with.
Some detectors in this slow-motion type design have a delayed response time, such as the Garrett Ace 250 or White's lower-dollar Prizm or current Coinmaster models. Others on the market, such as the Omega or Delta or Tesoro's or quit a few others can display a quick-response/fast-recovery. The processing circuitry tat provides the demonstrated quick-response in an "air test" shows us what the detector is capable of in an "air"-type environment.
I can work some wood-chip-filled playgrounds that have a fairly deep wood-chip base and that , usually, allows me to hunt them quickly with my Omega and still get decent quick-response and fast-recovery with a brisk sweep speed. If the site only has a shallow-depth layer of wood-chips (non-iron mineral make-up) but 2"-3" below I start encountering some higher mineralized ground or even pea gravel or rocks, then I need to be more concerned about sweep speed. Where I live, most of our ground is rather mineralized with a high iron content and the Omega, like most other 2-filter types, need to be worked at a slower sweep speed.
If the search coil is swept too fast over high iron content ground, you can sort of swamp the processors with too much ground signal to process out and pass along the target signal. This is my description in normal-speak terms and not necessarily an engineer's description, but it is what it is. Mater of fact, I encountered a site yesterday that I need to revisit this week after break from the rain. It's a very old park that used to produce some V nickels, Indian Heads and Barbers, located in a smaller town. They have groomed the center portion of the park and taken away 2"-6" of dirt. I came across it yesterday and hunted the west fringe area before the rain arrived, using my Omega.
The area I hunted was mostly bare dirt and the Omega worked okay, until I encountered the area where they have already laid down rock over most of it to get ready to pour cement. In that area, trying to handle the intense mineral body conditions of the pea gravel and rock they have put down over the scraped dirt, the Omega struggled to work well. I had to use a slower sweep speed or I couldn't get good target response performance. In challenging ground environments like that I always do better with a model that is a 3-filter design, and I also use a unit with a true 'zero' Disc. setting. Only the T2 adjusts that low in Disc. of any Teknetics. Today I'll work it with my MXT Pro simply because I can use a little faster sweep speed w/o loosing performance
Only you can determine the best sweep speed for your needs with your Omega and the search coil chosen, based upon the ground mineral challenges you will face, and the density of targets at the site. Tone ID choice can also influence the sweep speed/target response performance with some models, so take the time when afield to learn the limits of what your detector and set-up will allow.
Monte
