PI versus VLF versus Hybrid in plain english

[Charles (Upstate NY)]

I just got off the phone with Dave Emery. I'm still absorbing the truck load of information he gave me but I think I have a better understanding from a practical sense of the difference between a PI, a VLF, and hybrids of the two technologies. And I think I now have a way to compare one hybrid to another.

Without going into the technical details of why, in general...

1. PI's go deeper on a nickel than on a silver coin e.g low conductive targets, and are better in mineralized soil and wet salt beaches.

2. VLF's go deeper on a silver coin than on a nickel, high conductive targets, and have more difficulty with mineralized ground.

Its well known that the Explorer is a silver sucking monster, in my experience it gets much greater depth on a silver dime than on a nickel. Yet people comment that it gets better depth on a nickel compared to some other VLF detectors. That would seem to suggest that its PI like technology is giving it an edge. I have also heard that the Exlorer is better in mineralized soil and salt beaches, another PI like trait.

Yet the key point is that the Explorer goes deeper on high conductive targets than on low ones and so I would say overall its weighted more towards a VLF than a PI in terms of its technology.

Whats going to be interesting is comparing a hybrid that is weighted more towards the PI than the VLF technology. Logically you gain depth on low conductive targets, and performance improvements on wet salt beaches and highly mineralized ground. The burning question is, how well can you design around the PI's limitations when it comes to discrimination and depth on high conductive targets.

Charles

 

[Cody]

Nice explanation and explains some things I have wondered about with the Explorer.

 

[Steve(MS)]

n/t

 

[RingProfessional]

He used a garden spade to dig foot deep holes and he found loads of deep old stuff gold chains the lot, Oh and yes he did dig tons of trash.

 

[Charles (Upstate NY)]

At this moment in time the surf devil (waterproof model) has only three tones, low/iron medium/nickel high/silver BUT the pulse devil (land model) has variable tone ID from low to high. I quizzed Dave on this as to how many tones e.g. is it something akin to a Sovereign which can't tell the difference between a penny and a dime or something more like the Explorer, its more like the explorer. So you have both a disc feature to simply null out iron, foil, whatever and you have variable tone ID that would let you disc in your head via tones. That would be akin to an Explorer in IM-16.

Charles

PS: I lobbied him to include the variable tone ID on the surf devil too. I hear some water hunters only wanted 3 tones but I'm used to the Explorer on the beach so I want all the tones.

 

[Cody]

Let me run this past you. I need to know only two things when I hit targets. Is the target iron or not and if not then I need to dig it up to see what it is. I have long believed that there is little value in more than two tones, one for iron and one for everything else. I read the operators manual on the T-2 and they go into a lot of things about the detector and how to use it that I have always considered fundamental. Discrimination is a best guess as external noise, soil minerals, and other factors prevent an absolute ID of any metal in the soil. I think it can be done in the air but not in the ground.

I crank the Explorer down to just three tones, one for iron, one for medium conduction and one for high conduction which when using ferrous tones is iron, medium nonferrous, and silver. Even if I know one coin from another I am still going to dig it up. Now what I want to know is if the targets is a ring or pulltab.

 

[Charles (Upstate NY)]

Well first if you attempted to dig every non-iron target at my sites you would go home most days with little more than trash and a few clad in your pouch, its that thick. I only have limited time to hunt so I have to cherry pick the old stuff but even if I had all day I could not justify the time spent digging all the trash and clad out of the way when I can still cherry pick several good finds and not dig the trash. Thats why I bought the Explorer, it can often get me a piece of the good target amongst the trash therefore I dig more good targets than trash. Makes sense to me.

I once attempted to detect this way at a site that had given up hundreds of old coins. I spent a solid hour digging every target and managed to only clear about a 3x3 foot area. I found...trash and a couple clad coins. In that same hour I can usually find 1 to several old coins and relics by avoiding the trash.

What about Beach Hunting? Yeah I know, Charles are you nuts if its not iron on the beach you dig it. Yes except when the beach is sanded in somewhat and there are lightweight targets all over the damn place e.g. those freaking zink cents. You got 4 hours to hunt as much beach as you can, keeping in mind that you might have to drive and try more than one beach, or you are zooming from one lifeguard stand to the next. Now there's only 2 hours of low tide left and you have not made a good find yet. Do you keep digging all those zink cents or concentrate on silver/gold signals which are far fewer?

Assuming that you cannot dig every non-iron target in my area, tone ID is very important. I can move quickest hunting by tone, if I have to sweep and check my screen on every target for some clue to its ID I'll cover a fraction of the ground and make less finds per hour.

The variable tone ID also makes those averaged together targets stand out like a sore thumb. The silver/rusty screw cap, or the silver/nickel stuck together. As I have said before after a while you can hear the difference between good targets and junk, there is a shape and purity to the tones or a lack thereof. Few people believe me but I can call my shot on the difference between a barber dime and a merc with pretty good accuracy.

No thanks, give me variable tones and I'm happy.

 

[Cody]

I have very poor hearing in one ear and the other is not that good so I am sure that makes a huge difference. I can hear obvious differences but not between one dime and another. It would take something that caused one to really sound different for me to know and then I would still dig dig them up. I guess aluminum trash, rings from pulltabs is about as many problems as I have.