Threshold control on the F75...a definitive answer

digger27

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May 18, 2011
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This is about spreading misinformation, rumors...something that just bothers me to no end for some reason so a little rant if you would indulge me.


In our hobby we get lots of information from many different sources, most true, some not, some just rumors and some statements that many take as gospel made by people you would think would have a handle on the truth but in reality are just guessing.

In my life I have learned to take most information I get with a grain of salt, true things can usually be proved if you dig down far enough and you know that old saying about what can happen when you assume.

For years it bothered me that in one instance on one particular unit there was much misinformation being passed around and even though the truth was out there and could be found many never did and sometimes made buying decisions based on false information.
This was about the F4 and whether the ground balance setting would transfer over from all metal to disc.
The truth is it didn't, Dave Johnson came on and said as much in a few posts but still this wrong information persisted.
It sure didn't help that when you called some dealers and asked many said it did transfer.
This could have just been ignorance or it might have been a sales technique but in my world if this information was passed on purposely just to sell a product I have another word for it...lying.
The bigger problem was there were many that called FTP and asked this same question and depending on which tech you talked to you would get different answers...some would say it did, others would tell you it didn't.
I don't think in the factory's case it was lying but more of a case of bad communication and not enough training.
But still when they told customers the wrong information it was a disservice and helped to keep this misinformation floating around for years.

Recently on another forum we have been having a discussion about using monotone and maybe having some unmasking advantages on the F75 platform.
In this thread the subject of using the threshold control came up.
On the F70/Patriot we have complete control of this feature in both all metal and disc but on the F75, as far as I knew after reading the manual and posts from several owners, only one of the two all metal modes can you change the threshold settings.
This is where that misinformation thing popped up again.
One owner called a major dealer and asked about this and he was told by the rep that if you set the thresh in all metal it would indeed transfer over to disc, and this hunter believed him.
I replied this sounded totally bogus, it that were true you would think they would put this in the manual since adjusting the threshold in disc might be an important feature the company probably would want to share with their customers that might want to actually try to use it to their advantage.
Then another member posted he called the factory and the tech there told him the thresh would transfer over to disc on the F75 but only if you set it at +2.
My jaw dropped a little on that one, I can't say for sure this is true and any tech at the factory would ever have actually had this ridiculous statement come out of their mouth but then again there was that F4 stuff that went on for years.
This is how rumors start and how they keep going...don't know why this bothered me at all, I don't even own an F75 but for some reason I felt it had to end asap.
I posted that unless someone with credentials we can trust comes on and addresses this exact subject if I owned an F75 I would assume what the manual says and just assume the threshold can only be adjusted in one all metal mode.
That is when one member sent a message to Dave Johnson and asked about this.
He came on the forum eventually and posted this...

Re: Monotone?
Posted by: Dave J. [ Send a Message ]
Date: June 07, 2017 03:45PM
Registered: 10 years ago
Posts: 914

Been a few years since I swung an F75, I handed the question over to John Gardiner, the engineer who wrote the code that runs it.

Reply Quote Rep




Re: Monotone?
Posted by: Dave J. [ Send a Message ]
Date: June 07, 2017 05:23PM
Registered: 10 years ago
Posts: 914

Johnny says no on F75, yes on F70.




So there you go, if for whatever reason you own or are thinking about owning one and threshold control in disc is something important to you this is information you can trust from the guy that designed the machine and the person that programmed it.
As the X Files show used to say, "The truth is out there"...it is just up to us to find it.

None of this matters much to many, the F75 is amazing and even without being able to control the thresh in disc this is really a non issue, it doesn't affect many hunters in the slightest but it just bothered me that even a few might believe things they heard but were not true at all.

However if this information is of interest to you this is the truth, the gospel...straight from the source.
Now you know.
 

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Charlie P. (NY)

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Before this post if you had asked me I would have said the F-75 is silent search in any Disc setting and in All Metal you can set the threshold and then have a choice of a range of pitches for the threshold tone.

The manual Ground Balance can be accomplished in all metal and transfer back to discrimination if you wish.

I never heard anyone claim that the F-75 had a threshold tone in the discrimination mode. Mine doesn't. Maybe a background interference from wireless headphones?

So I looked in my manual.

Threshold is adjustable in All Metal mode but NOT the static mode.

Not mentioned at all in Discrimination mode.

In fact, the manual says this (my underlines):
Sensitivity
This controls the signal gain, and is adjustable from 1 to 99. Unlike the All Metal Modes, the
Discrimination Mode is designed to operate silently
. If you hear noise when there is no metal
present or when the searchcoil is not in motion, reduce the Sensitivity setting until the machine
goes quiet. NOTE: there is no interaction between the sensitivity settings of the All Metal
and Discrimination Modes.

If someone thinks they have a signal tone in discrimination mode they are just fooling themselves with an over-gain signal overload in the circuitry. Not a threshold tone. Like turning the squelch/gain on the VHF or CB to the point where you just get static instead of clear signals.
 

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digger27

digger27

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May 18, 2011
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Yea, not that you would actually hear a threshold tone in disc but more about people thinking that you could adjust the thresh in that one all metal mode anywhere from -9 to +9 then switch over to disc and that custom threshold setting would transfer over.
It just doesn't.
On my F70 or the Patriot we can adjust the thresh in disc.
There is no threshold tone in disc but all settings are affected by your thresh settings, definitely.
I don't get crazy with the thresh all the time when I hunt in disc but I have from time to time just because I can...and a few times I have been very pleased with the results.
Again for most a non issue, the F75 finds great things pretty easily in disc without this ability but people believing it actually could do this just bothered me when I knew it wasn't true.
 

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Charlie P. (NY)

Gold Member
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Primary Interest:
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Never really thought of a threshold tone as an "ability". Like saying "with this jet the engine noise can be heard in the cabin".

Some prefer silent search. I find threshold tones annoying. Like listening to a dial-tone or the hum from bad speakers.

In the old analog machines it was a way to assure you were tuned as best as possible and the batteries were still alive. Went down for iron and up for non-ferric.

I usually run in Disc with a setting of "5" and no notch. I just watch the TDI to see if it's iron or possibly other junk. Silent but high-gain.
 

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digger27

digger27

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Never really thought of a threshold tone as an "ability". Like saying "with this jet the engine noise can be heard in the cabin".

Some prefer silent search. I find threshold tones annoying. Like listening to a dial-tone or the hum from bad speakers.

In the old analog machines it was a way to assure you were tuned as best as possible and the batteries were still alive. Went down for iron and up for non-ferric.

I usually run in Disc with a setting of "5" and no notch. I just watch the TDI to see if it's iron or possibly other junk. Silent but high-gain.

Oh yes, being able to raise the thresh in either all metal or disc is an ability and a great feature...not only can it affect depth, or more precisely pick up more targets smaller and/or deeper, but I have found high thresh can have some uncanny unmasking abilities especially when hunting around a lot of iron.
All my sites are mineralized with tons of trash and insane amounts of iron and I have explored and experimented with the thresh setting in both all metal and disc for many, many hours on a large amount of my hunts.
Mostly high thresh settings.
A whole bunch of extremely masked to the hilt coins were the result including many silvers.
 

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Rawhide

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Disc modes are just that discrimination. Never tried to adjust threshold in Disc modes. While the left side and right side of the screen do share some settings I doubt the threshold would be a benefit in disc modes. F75 is a proven detector, all this has been discussed. Sorry folks get mislead. Most times its the operator misunderstanding the answer.You went to the right folks. I have owned the F75 for years and my finds speak for themselves. I own two other brands also, love em all.

I bet the threshold on F70 may have a advantage. I have heard the new Patriot to be a rebranded F70. I would say your not wasting your money. The F70 came out after the T2 and F75. So the Patriot may be the best machine new machine out there right now.
 

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digger27

digger27

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May 18, 2011
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The F75 is a great detector, works fantastically and as I said not being able to control the thresh in disc is a non issue, but I can and have used high thresh in disc and there are definitely provable, tangible benefits...for me.
Do you ever hunt using yours in all metal, and where do you set your thresh level if you do?
I do using many different threshold levels and that is the first way I experimented with very high thresh which is something any F75 owner can do and still my best and most successful way to hunt in extreme iron...still do it that way more than I ever do using disc to this day.
Lower thresh works too, higher thresh for me works a bit better or at least I learned to use it to gain a little advantage in my particular sites.

Just one combination of settings I have learned that works and I have many more that are totally different...vastly different, but I just really enjoy tweaking my detectors in different ways just to see what might happen.
I am very curious so this is a very enjoyable part of the hobby for me, almost as enjoyable as hunting and finding great treasure.
Sometimes good things happen, sometimes they don't so I file away the better ones and disregard the rest.

The great thing about these units is there are so many ways they can be set, completely different ways that can all lead to success.
 

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chub

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Never really thought of a threshold tone as an "ability". Like saying "with this jet the engine noise can be heard in the cabin".

Some prefer silent search. I find threshold tones annoying. Like listening to a dial-tone or the hum from bad speakers.

In the old analog machines it was a way to assure you were tuned as best as possible and the batteries were still alive. Went down for iron and up for non-ferric.

I usually run in Disc with a setting of "5" and no notch. I just watch the TDI to see if it's iron or possibly other junk. Silent but high-gain.

The F5 had adjustable thresh and gain in both modes -all metal and discrim. I went out one night with the F5 in one hand and the F75 in the other. Sure they 'air'test the same or similar but the truth is (for me anyway) the F75 simply blew the F5 into the weeds. I was crushed as I loved the F5.

The threshold is useful for detecting ,or rather hearing/ amplifiying, faint signals on the periphery of the detectors ability (or current gain setting).
This is why some people find it such a useful control. When I ran the F5 it WAS a great feature....until I got the F75. The F75 was just that much more powerful than the F5. Signals that were scratchy and iffy on the F5 were clear and strong on the F75. I had hundreds and hundreds of hours on the F5 and knew it inside out and back to front.
I went back to all my old sites that Id hunted out with the F5 and was shocked at what it had missed!

So in my opinion a powerful machine on silent can blow a weaker machine into the weeds with high gain and thresh settings.

I would love a F70 to add to my collection but just cant afford it right now.

Chub
 

HighVDI

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For some reason, I just can't get the hang of all metal mode in trashy areas. Maybe I have to get a better ear for the goodies in all metal instead of screen watching.
 

chub

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For some reason, I just can't get the hang of all metal mode in trashy areas. Maybe I have to get a better ear for the goodies in all metal instead of screen watching.

With the F75? using the push the shovel in to break the halo trick may help initially. But trash is trash . You may get a similar depth in discrim with a fast sweep than a slow sweep in AM. Only saying that because I tend to slow down the sweep when listening hard.

Chub
 

vferrari

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Great. Now if someone can get to the bottom of the mystery as to which display indication (9.0 or 9.1) corresponds to DST EMI filtering ON, then all the F75 truthiness will be out there. Thanks. Lol.
 

vferrari

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Charlie P. (NY)

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I was told the manual is correct: "90" is DST on, "91" is DST off.
 

darktower007

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Great post DIGGER! The f70/f75 had so many hidden gems in them.. I'm looking forward getting mine back from the repair shop.


Sent from my iPhone using Tapatalk
 

chub

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I was told the manual is correct: "90" is DST on, "91" is DST off.

Thats also how I understand it. some say 9.0 = 100% "on" shielded, and 9.1 =80% "off"

but vferrari has a point. a bit like the se, ltd,85th etc. I have the latest version and I must say its quiet and deep. Love it!
 

HighVDI

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Let me look at my manual, since that 9.1 I quoted is what I THOUGHT it read......lol. Definitely does seem to be some confusion over it here. You would think the company that makes the machine would tell us the correct setting? Crazy
 

HighVDI

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If it is 9.0 then that explains why my machine has been a little chattery lately. It's currently set on 9.1.
 

vferrari

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Thanks. I'm going with 9.0 = ON as that seems to be the most frequent answer, is the one in the manual, and what at least one First Texas rep stated in an email. But there is no way to definitively verify it and the subjective reports of improved depth performance with 9.0 still leave doubts in my mind (I am a firm believer that their are no free lunches when it comes to detector settings i.e., I would expect depth performance to suffer with enhanced EMI filtering). Thanks again for indulging me in discussing the off topic subject.
 

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