From this detector EE, ET, and EM's viewpoint, Fatheadnc is pretty close to the truth.
Garrett Aces 100 through 750 and the 1250 through 2500 really DO suck in high iron soil, almost to the point of being embarrasing and a worthwhile trip to the nearest tavern to mull it over a bit. Even the F-2 and F-4 handle bad soil and hot rocks better than the Aces do, by far, and they do fairly well on high iron/salt beaches too. Hot rocks don't seem to bother them either.. Garrett's own charts (exclude) the Aces for beach hunting.
The MXT with the stock 9.5 coil has a real tough time in hot rocks and high iron soil. It's the 9.5 that ruins it, but a smaller or larger White's coil will do just fine in your soil. But a cz will go deeper.
ALL Fisher cz's do very nicely in your soil and even here - where the soil is even worse than there in AZ. And I mean CONSIDERABLY worse! Some of the soil here in Oregon and Washington has as much as 1/3 of a cup of iron filings in a cup of soil.
The lower priced Tesoros with auto ground balancing do very well in AZ, even better than the higher-priced Tesoros with manual ground balance. It's because Tesoro uses a lightning-fast-reference tank circuit - along with a super fast retune - plus a superbly fast return to (silent) threshold in the cheaper models which have no manual GB , all used in the 4 cheapest Tesoro detectors. . It really makes a big difference too. A well-designed auto GB is ALWAYS better than a poorly balanced manual one, and if you doubt that then go read Tesoro's own engineer's notes.. Tesoros higher end ones have a VERY tough time with high iron situations and you can't ever completely ground balance them in high iron soil at all, especially the Cortez and the Tejon. Tesoro can and will calibrate their detectors to your particular soil, but who wants to fool around with that?
MINELABS do handle bad ground well but do not go very deep in your soil - or here either, save for their PI's, no matter what person has which dream.. OR "vision" to the contrary. In fact, coil size for soil size my tests have proven that Minelab multis or any VLF Garrett are not capable of as good a depth as any cz ever made, and especially in hard soil full of magnetite or hematite.
The Garrett 1200-2500's though do very well for depth in very light or iron-free soils. It's because most Minelabs use too slow of processors - and the Garretts still use 1980's circuitry designed primarily for the eastern USA and Central European soils.. And don't believe the barnyard fertilizer stuff about ANY detector using more than one frequency at the same time, it's impossible. If they did it would make the detector sound like a popcorn machine running and a rock and roll song blaring, with a 5 year old birthday party going on in the background. Multi's use only one freq at a time and continually sample the soil matrix to determine which freq (might) work the best in any split second. This causes them to operate too slowly in bad soil and to have to be swung very slowly just to start with. Poorer-than-average-depth is commonly the result, and that's why many single freqs usually go deeper in high iron soils. The cz Fishers though are not the general rule of thumb due to their inherently fast processing, a patented circuitry concept.
The DFX is a fair depth machine but it is not as deep as a cz or an older Compass in (your) our bad soil.
A Nautilus will go VERY deep, and sometimes even deeper than a cz, but you would have to marry yourself to retuning it every 5 minutes or so, and it is a real heavy dude - at best.
Oh, and John, the DD was invented by Compass Electronics to compensate for "noise" AKA "interference", AKA as "false signals" from too much iron to discriminate against, be it in the ground, or from any other multiple iron items. Remember that the "ground balance control" is little more than a "rough "discrimination control", akin to the course adjustment on a short-wave radio - as compared to the fine adjustment on one. The concentric or stacked (coaxial) coils go deeper than a DD of the same diameter - but the DD's do handle bad ground better because that's what they were designed for.
*Just a little practical advice and info from a former detector engineer, electronics technician, detector repairman, and electronics mechanic.
Hope this helps
EasyMoney
