Manticore And Emi (and The Magic Word -- Depth)

[abenson]

6 hours ago, TampaBayBrad said:

This discussion on sensitivity setting made me go back to find and re-read an answer that NASA Tom gave you on page 18 of his Manticore thread. He replied:

"Andrew...... is there ANY chance you could run Audio in Prospecting......... and a Sens of 22? ----The performance you are ascertaining on the 16" Nickel is EXACTING for a Sens of '21'........and a: Tones audio Mode. MANY things start to 'happen' when Sens is on 22 (and 23 & 24 !!!).........but 'Prospecting audio' is key."

The part that's interesting to me is where he says "things start to happen when sens is 22 and 23 and 24."

This kinda tells me that you SHOULD try to run sensitivity as high as possible without covering up/masking target tones with background emi noise.

He speaks as if there is a benefit to run as hot as you can when he says "things start to happen".

Simon....your above comment:

"deep targets can still be found on sensitivity of 12 with reasonable results, 14 seems the sweet spot for me.  Cranking it up to 20 to 35 just isn't necessary and can in fact make the targets harder to find."  

That is what got me trying to find NASA Tom's reply to abenson. Seems you may be losing something running the sensitivity that low if it is possible to crank it up a bit.

 

EMI is not the limiting issue at the beach I hunt, salt content is. I can run the sensitivity up to about 26 or 27 before EMI makes the Manticore to chirpy to use, even with a long press noise cancel.  So if I back the sensitivity down to 25 where there is very little EMI and lower the coil to the sand and ground balance. I still get multiple false signals as I sweep the coil. Lowering it to 22 it about where you can hunt comfortably in most places. some require lowering it to 21.

I guess if someone wants to chase multiple false signals in hopes one will be a deep target then the more power to them. I already dig multiple signals that never produce a target each time I go. It isn't like you can just take a scoop of sand out and if the target disappears pass on. The Manticore, like most SMF Minelabs I have used, (and yes I've seen it with other brands) are famous for targets disappearing once the sand is disturbed. So it's all or nothing at that point. You either dig until the target is out at about the 13-14" range or you dig a 20" deep hole just to make sure there's nothing down there. I personally don't have the time to to chase false signals.

I can sit and screw around with settings on the 16" deep nickel I buried, using every mode, audio profile, audio type, noise cancel, GB, etc. and get it to come in a little better. But when I try and use those same settings to actually hunt it's not feasible.

There are 3 of us with the Manticore in my area that hunt the same beach. You can ask any of us what our settings are and my guess is they are pretty close to the same.

[TampaBayBrad]

21, 22, and 23 Is also where I wind up with the salt content of the gulf beaches. I guess my post was more directed at anyone that may be lowering the sense way down so it is all the way quiet when swinging. I think you may be losing depth at that point.

At my setting, with prospecting audio in use, a target jumps out above any emi/salt chatter pretty clearly even though there is SOME chatter going on with my coil movement.

[JCR]

6 hours ago, TampaBayBrad said:

This discussion on sensitivity setting made me go back to find and re-read an answer that NASA Tom gave you on page 18 of his Manticore thread. He replied:

"Andrew...... is there ANY chance you could run Audio in Prospecting......... and a Sens of 22? ----The performance you are ascertaining on the 16" Nickel is EXACTING for a Sens of '21'........and a: Tones audio Mode. MANY things start to 'happen' when Sens is on 22 (and 23 & 24 !!!).........but 'Prospecting audio' is key."

The part that's interesting to me is where he says "things start to happen when sens is 22 and 23 and 24."

This kinda tells me that you SHOULD try to run sensitivity as high as possible without covering up/masking target tones with background emi noise.

He speaks as if there is a benefit to run as hot as you can when he says "things start to happen".

Simon....your above comment:

"deep targets can still be found on sensitivity of 12 with reasonable results, 14 seems the sweet spot for me.  Cranking it up to 20 to 35 just isn't necessary and can in fact make the targets harder to find."  

That is what got me trying to find NASA Tom's reply to abenson. Seems you may be losing something running the sensitivity that low if it is possible to crank it up a bit.

 

The reply from NASA Tom to my post about True All Metal on a SMF detector was interesting regarding Prospecting audio.  If it behaves similar to a Threshold based true All Metal channel it may explain how Sensitivity could be run higher. That is good information to know for Manticore users. I may repost my question here on DP for the more general answer I was hoping for.

[abenson]

I personally don't like Prospecting theme unless I'm prospecting and the reason is that everything sounds the same, including false signals. Those false signals can be mineraliztion, salt and iron. My brain is better at processing all tones audio, I think I can better distinguish a good target from bad/false using a multi tone audio. I know some people can't stand it, but I actually prefer it. I've tried prospecting theme at my beach and for me it's really hard to know what's a false signal and what's a deep target. Could just be my hearing., I don't know. In the end I have to use what works for me.

[phrunt]

Nasa Tom speaks so cryptic it's hard to know what he means half the time 🙂

If he ever writes a metal detecting book Google will need to configure google translate to have Nasa-Tom mode so we can run the Ebook though it to translate to English.

I appreciate his role as a tester of the detector and I'm sure he gave plenty of good feedback to the engineers that built the thing but once it's in the hands of the public they become the testers, testing it out in their soils and for their targets, inevitably they will notice different things which may have gone unnoticed for him with his hunting methods and the other testers involved with pre-release testing.  They are just another person with an opinion at that point.

He may well be very well versed in finding targets in his area for the targets he looks for, throw him in someone else's shoes in their soils and with their target choices and he may well be out of his depth.

I don't take what any single person says as gospel and I certainly trust what I see with my own eyes over something I'm being told from a guy far far away.

Lowering sensitivity too far can reduce depth, of course it can. but raising it too far can be detrimental too, especially with the Manticore where this is somewhat more noticeable than some other detectors,  I run just about every detector I own maxed out or as near to as possible, it's how I usually hunt, but not the Manticore, I run between 16 and 22 mostly and I am seeing at those sensitivity settings it's outperforming the Nox on sensitivity 25 at depth on coins.   I have found spots it runs at 35, and in those places I do let it stay on 35, it's all based upon where I am using it and I've found backing off a few numbers improves target identification which also improves target trace of course.  The point is with the Manticore you don't need to be scared if you're in lower sensitivity settings you will loose deep targets, you will find it ID's them very well in lower sensitivity, better than the Nox did.

[UT Dave]

I've only used Prospecting audio for about half an hour on the beach.  Didn't care for it, same reasons as @abenson.  I like full tones, that's how I ran my XLT and my Nox and it seems to be how I'm going to like running my Manticore too.

- Dave