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

[abenson]

I'm not going to pretend I know what's going on when you do a long press noise cancel. But when you do it will cycle through the channels and change between them until it finds one it likes. So you will see it land on -9 then 1 then 4 then 1 again and 1 again, when it sticks to one channel that's when you knows it's found the channel it likes. It seems to work and does quite the machine down.

[Chase Goldman]

2 minutes ago, abenson said:

I'm not going to pretend I know what's going on when you do a long press noise cancel. But when you do it will cycle through the channels and change between them until it finds one it likes. So you will see it land on -9 then 1 then 4 then 1 again and 1 again, when it sticks to one channel that's when you knows it's found the channel it likes. It seems to work and does quite the machine down.

Yep.  So that definitely optimizes the quietest channel. But I am trying to reconcile Steve G's point (based on Tom's statements) that it also somehow obviates the need to do Tom's "silent" EMI air test - which implies more than just finding the quietest channel.  I will follow up with Tom since he now has my question.  Frankly though, I believe I am splitting hairs.  I personally have not ever fretted about silent EMI, but the statement is out there by Tom so I'm simply curious.  And if the Manticore is really just finding the quietest channel by repeated scans and nothing more, that in itself a decent incremental improvement over Nox.

[Dug D]

I stress I have no special or secret evidence or information regarding how the long press works, but my first thought was it picks the best channel to be quiet and also auto adjusts the sensitivity till its quiet. Sorry my brain works this way, it just seems to be the easiest way to achieve quiet operation. I prefer the thought of super advanced tech that eliminates all EMI, and I am hoping for that.  

[TampaBayBrad]

53 minutes ago, Dug D said:

I stress I have no special or secret evidence or information regarding how the long press works, but my first thought was it picks the best channel to be quiet and also auto adjusts the sensitivity till its quiet.

That would be nice, but according to NASA Tom, that's not what it's doing. He says AFTER each long press readjust sensitivity to the highest possible setting. So, in short, the quietest channel allows YOU to adjust sensitivity higher.

This is partly how he arrived at his 23% deeper than nox....Manticore handles EMI better, thereby allowing you to crank up the sensitivity hotter.

[cjc]

This is a detector with a heavily processed signal--period.  This creates a delicate balance in that while this processing is augmented with a lot of  power--physics are physics.  So with the Manticore, everything is there in the signal tone--EMI, proximity of targets, mineraliztion in the ground, sweep or REC SPD too  fast--its like the signal  is being crept up on by this wave of generalized interference--not just electrical EMI.  This is reflected in how well  targets sounds stand out. Try turning the  machine on indoors at Sens 30.  Listen to a few targets while  greadually turning it down.  As you  reduce the Sens, the processing stops  working against you--confounding the signal.  Way down at say 15 you finally have  a signal tone that is standing out from the background.  Signal to noise is a big part of understtading this machine--like the NOX.  However, the Manticore is a lot more refined in that even with a lot of noise--it's still going deep in kind of a faint tone way...The "I'll turn it up and learn to hear though everything" guys  are not going to get far  with this one--it needs to be  run and listtened to  in  a balanced, measured  way.   Its not a loud, robust signal but it's a deep one.  This is the processing--it's sampling at an extreme ratio- like the NOX  it does not at all sound like its going deep but it is.  Kind of  funny the ads talking about all this power--but up past 25 you are already in trouble with the audio tightening up and clipping...

Tip?  Focus on peaked sounds.

I can see that this machine will be challenging, but worth learning.

cjc

[abenson]

53 minutes ago, cjc said:

This is a detector with a heavily processed signal--period.  This creates a delicate balance in that while this processing is augmented with a lot of  power--physics are physics.  So with the Manticore, everything is there in the signal tone--EMI, proximity of targets, mineraliztion in the ground, sweep or REC SPD too  fast--its like the signal  is being crept up on by this wave of generalized interference--not just electrical EMI.  This is reflected in how well  targets sounds stand out. Try turning the  machine on indoors at Sens 30.  Listen to a few targets while  greadually turning it down.  As you  reduce the Sens, the processing stops  working against you--confounding the signal.  Way down at say 15 you finally have  a signal tone that is standing out from the background.  Signal to noise is a big part of understtading this machine--like the NOX.  However, the Manticore is a lot more refined in that even with a lot of noise--it's still going deep in kind of a faint tone way...The "I'll turn it up and learn to hear though everything" guys  are not going to get far  with this one--it needs to be  run and listtened to  in  a balanced, measured  way.   Its not a loud, robust signal but it's a deep one.  This is the processing--it's sampling at an extreme ratio- like the NOX  it does not at all sound like its going deep but it is.  Kind of  funny the ads talking about all this power--but up past 25 you are already in trouble with the audio tightening up and clipping...

Tip?  Focus on peaked sounds.

I can see that this machine will be challenging, but worth learning.

cjc

Totally agree with you on this. People that don't have the machine don't understand this. I have people continually telling me on my videos to turn the sensitivity up on the Manticore to get better depth/performance. There are 4 major things that are going to determine how high you can run the sensitivity and not get yourself in trouble. EMI, density of iron targets, ground mineralization and on the beach salt. One or more of these are going to determine how high you can run sensitivity. Just because you can do a long press noise cancel and run the sensitivity up to 30+ while holding the coil in the air, doesn't mean you can hunt that way. I've located many deep targets on the beach that if I had the Manticore over powered, I wouldn't have heard the signal through all the noise. High sensitivity on this machine is counter productive.

[phrunt]

This is correct from what I've seen, I ran my Nox on 24 or 25 it's entire life, rarely did it come off that and I didn't feel the need to either except in the worst EMI environments but then I generally went to single frequency, as I was mostly prospecting where there was EMI, and switching from Multi to 40kHz was no big deal to keep the sensitivity maxed out.

The Manticore is very different and I've done side by side testing with the Nox, 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.  I just don't feel the need with the Manticore to crank it right up, it's not how the Manticore works.    At sensitivity 14 it's keeping up or exceeding the Nox on 25 anyway.  I just run mine at whatever sensitivity level gives me no EMI issues at all knowing because my sensitivity is lower I don't have to be concerned about depth/performance.

[cjc]

7 hours ago, abenson said:

Totally agree with you on this. People that don't have the machine don't understand this. I have people continually telling me on my videos to turn the sensitivity up on the Manticore to get better depth/performance. There are 4 major things that are going to determine how high you can run the sensitivity and not get yourself in trouble. EMI, density of iron targets, ground mineralization and on the beach salt. One or more of these are going to determine how high you can run sensitivity. Just because you can do a long press noise cancel and run the sensitivity up to 30+ while holding the coil in the air, doesn't mean you can hunt that way. I've located many deep targets on the beach that if I had the Manticore over powered, I wouldn't have heard the signal through all the noise. High sensitivity on this machine is counter productive.

Ya, many dont understand that all multi FQ machines will give a smooth T/H no matter what.  Just that way up at 30 nothing is jumping  though.  The better the processing, the smoother--conditions notwithstanding.

cjc

[UT Dave]

Absolutely agree with the less sensitivity so far with the Manticore. Today on really nasty wet salt, I was running 21 most of the time, went down to 20 more than up to 22.  Ground balancing often, the machine would start telling me when it was time.  Kept the machine running a bit chirpy, but not too bad for the conditions.  Pulled two silvers from 12-14 inches each in that nasty salt.  At 20 sensitivity.  And the silver Washington was banging hard 90-92 at 14 inches.

- Dave

[TampaBayBrad]

16 hours ago, abenson said:

Totally agree with you on this. People that don't have the machine don't understand this. I have people continually telling me on my videos to turn the sensitivity up on the Manticore to get better depth/performance. There are 4 major things that are going to determine how high you can run the sensitivity and not get yourself in trouble. EMI, density of iron targets, ground mineralization and on the beach salt. One or more of these are going to determine how high you can run sensitivity. Just because you can do a long press noise cancel and run the sensitivity up to 30+ while holding the coil in the air, doesn't mean you can hunt that way. I've located many deep targets on the beach that if I had the Manticore over powered, I wouldn't have heard the signal through all the noise. High sensitivity on this machine is counter productive.

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.