Honestly, everyone is different and seem to attack iron heavy sites in different ways and most seem successful.
Depends on you, mostly, and how you like to hunt...high disc, low disc, gain up, gain down, all metal or whatever.
A few things you should know...
Unlike many that hold to the high beams don't work in the fog, theory, that you lose resolution using higher gain vs low in trash or ion infested sites, on this platform, the F75/F70/Patriot/T2, all work better with opposite thinking.
Higher gain gives better resolution in packed and crowded sites, not lower.
Not easy to believe for some but true nevertheless...I have seen this myself many, many times.
In heavy iron, and believe me I have hunted in way more than my share of sites like that, I know two ways that work.
One is NASA Tom's low disc method...1 tone, (Mono), low disc, (I rarely use 0, mostly I stay between 1-4 with other settings as high as you can stand.
I have had some great success hunting an iron infested old farm house site this summer using what I call high power blast trough settings on the F70. All metal and all settings at max looking for any numbers or blocks of higher than iron numbers showing up at all that don't seem to be false high...
www.findmall.com
Actually, Tom has dive deep into this platform and came up with many great insights as to how these things really work out in the field so reading his stuff is recommended for a high degree of understanding.
Start with this....Google it.
Most F75 settings will transfer over to the F70 AND the T2 although slightly different disc levels on the T2 because of the larger iron range.
F-75 Peak Performance - Disc '6' & mandatory 'monotone' relic hunting justification
Some highlights...
When the F-75 is placed on a Disc setting of '6' and 'monotone'; This set-up config allows (under MOST circumstances) the best iron see-thru ability..... in locating non-ferrous targets in areas that are loaded with ferrous (usually nails) environments. The older the site....... the more nails will be present; subsequently, the more good targets will be masked. Most detectors will 'shut-down' under these scenarios. The F-75 (& T-2) are the only detectors currently available on the market that begins to tackle this type of (extremely common) scenario.... with some 'unmasking' success.
.... With F-75 Disc on '6' and 'monotone',,,,,,.....,,,,,, the moment you invoke a different tone option; Say 2-tone, 3-tone, 4-tone, etc.... the audio portion of the Disc, ....even though Disc is set on '6'...... will instantly become a Disc setting of '15'. What does this mean? = Any target that is between a Disc level of "6 thru 15" will now audibly report as a "Low Tone" (iron tone). BIG PROBLEM for a multiplicity of reasonings. Now, any target that is ABOVE a "15" (VDI reading)... MIGHT report a higher tone,,,, (tone freq depending on what tone option is invoked). -------Most folks do not dig iron. And most folks WILL miss masked non-ferrous targets when multitones are selected.
#1 On both the T-2 & F-75..... running a higher Sens gain in the trash (especially iron) presents a MUCH enhanced resolution on non-ferrous targets amongst iron. This is a paradoxical contradiction; what is....... but should NEVER be. Next time you find a non-ferrous target amongst high iron trash concentration (with high Sens settings)....... drop the Sens and see what happens. The non-ferrous target audio resolution will decrease.......possibly even disappear completely (depends how badly masked the non-Fe target is). The more masking... the HIGHER the Sens needs to be on the T-2/F-75. ((( This is not a typo )))!
#4 If you run Disc on 0-4 on the F-75..... all nails will report as good targets in monotone. With F-75 Disc on '6'..... MOST (not all) nails will report as a snap-crackle-pop....tick-click (not a solid audio); which, in turn..... can be ignored. Axe heads, hammers, gun barrels and other large iron targets will give a good audio with Disc on '6' on the F-75. .... But, MOST fields we hunt are not loaded with axe heads, gun barrels and hammers.
#5 The F-75/T-2 have a tendency to "up-average" non-ferrous target ID numbers when near disintegrated iron or bad minerals. VERY common occurrence. It is partial 'silent masking' coupled with conductive target response.
NOW.......... that being said. (((( If you are in a nail infested area, and you do NOT audibly fatigue easily = = = )))) IF, IF, IF, you can handle a lot of noise.... and the detector can handle (not EMI plagued) a Disc setting of '0' and a Sens setting of '99'....then hunt in 2, 3, 4 tones (your choice),,, hunting for the "deepies". YES.....the detector will mask some targets in this audio selection config (ie 2, 3, 4 tones are selected) because any (heavily masked) target that VDI ID's as a '15' or below will present a 'iron' audio response (as so stated in example above),,,,, BUT, the trade-off is; the F-75 will go deeper just by virtue of the Disc setting being '4' or below (especially '0').
Soooooooo, I am saying (by this set-up config) = MORE MASKING, BUT GREATER DEPTH. Hmmmmmmmm... trade-off. Which one does better? Disc '6' & monotone???? or Disc '0' and multi-tone???? The answer is: They BOTH do!!!!!!!!!
I am saying; HUNT the area in Disc '6' & monotone...... and perform all of the 'unmasking' that you can. THEN hunt in Disc '0' and a tone-option of your choice.... going for all the deepies.
NO...... you can not have both at the same time.
And more...
Google
When absolute maximum overdriven performance is desired:
.
I have YET to be able to handle a nail infested site with the detector in monotone.... and a Disc setting of '0'. This means that you hear absolutely everything.
It is not so much that a DE would over-engineer a detector to be audibly unintelligible; it's more a 'sensitivity function' of a gold prospecting capable unit..... coupled with a extremely fast microprocessor/clockspeed and very tight electromagnetic footprint emanating from the coil. Little flecks of iron will cause this particular detector set (F-75 & T-2) to sound electromagnetically unstable. On a recent hunt, I (as usual) was overdriving the F-75...and, in one area, it became electrically unstable (((so I thought))). Coil in the air.... and unit was stable. Coil on the ground and not moving.... and unit was mostly stable. Sweeping coil.... and EMI interference ensued. Hmmmmm....... let's dig some of these so-called "chatters". Resultant: About every 2" or 3"..... I was finding #2 lead shot from a shotgun.... at a depth of approx 1.5". I quit recovering them once I had about a dozen in my hand. The small spot of land that I recovered/removed these small BB's.... suddenly had no 'electrical chatter' in this one localized location of coil-sweep. Exterior of this sans spot,,,,, the electrical chatter resumed. I knew I was 'overdriving' the F-75.... and decided to drop the Sens to a setting of '70'..... and the perceived electrical chatter (the BB-shot).... as coil was being swept.... suddenly vanished. I had desensitized the detector enough to no longer detect these small targets,,,, and the unit became stable again. Masking was still taking place though. It hurts me to drop Sens to lower levels; however, I could ascertain a more stable/intelligible unit and could then somewhat "hunt". (Targets beneath these BB's are going to be partially or completely "masked"winking smiley.
Another known engineering fact is that a single freq unit has the ability to handle Fe better than multi-freq units. Both types of units are still blinded (masked & silent masked) by iron,,,,, but the single freq units can ID iron with better accuracy, less falsing.... and a hair-splitting Disc setting is more ascertainable with a single freq unit.
Also I have my own way to hunt in massive iron and trash, an insane way I call my Blast Through settings.
took awhile to learn to do this but now it is second nature and my go-to settings for hunting in heavy iron or just hunting in any site around here where I live because everywhere I go I have so much iron.
I learned to do this at an old farmhouse site that was absolutely infested with massive iron.
Nobody could make any headway here and left after one hunt never to return.
Neither could I, at first, but I was just to stubborn to leave so I continued to hunt learning, and using my all metal, maxed out everything else settings until I finally unlocked the mysteries of that very challenging site.
To this day learning to hunt in iron using either the low disc monotone or my Blast Through settings have been the most helpful skills I have acquired since I entered this hobby.
Since the 27th of last month I have been spending most of my hunting time at a farmhouse site I call the iron mine. A million nails of all kinds and sizes, iron wire everywhere and large pieces of iron too, very challenging and most that visit here come here once and never return. Stubborn ole...
www.findmall.com
Using this high power, punch through method, well known by others but new to me, is still working to perfection. In a site so loaded with an imaginable amount of iron and junk I am now able to pluck out good higher number targets at will while avoiding the million nails and dealing with masking...
www.findmall.com
For those of you following my adventures and experimental settings in extreme iron infested sites... As some of you know, I have been experimenting with different settings on my F70 trying to get through the unbelievable amount of iron at a site that had an old farmhouse at one time. There is...
www.findmall.com