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F70 Settings
Posted by: fjs440
Date: December 29, 2015 04:30PM
I just upgraded from the F2 to the F70 with an 11’DD and I am playing with it in the garage, because of steady, cold rain. (NE Ohio)

I feel like if I can understand the F70, I am going to love it. The F70 seems to be an overpowered psychotic monster wanting to get loose and it is my job to keep it under control. My F2 does a great job on reasonable depths, but I need more depth for the local black-sand beaches. They have been overworked, but they are the only things I am physically able to do standing up.

I have noticed that going to zero discrimination and slow speed cranks this thing up. Anything else quiets it down and gives it less depth. That can be useful for trashy areas, so that is good. So I start with slow speed and zero discrimination. (This reminds me of flooring a Corvette during the ‘60’s when I was young!)

I guess the question is, does Sensitivity or Threshold have more influence than the other on depth? Where should the settings start before I get rid of the noise? What else am I missing? You know more about this than I do. With a machine like this, I doubt there is a simple answer. I am just looking for where to start.

Hope you all find lots of goodies. Happy New Year!

Fisher F70 w/11” DD
Fisher F2 w/4”, 8” and NEL Hunter Coils
Fisher 1280-X w/8”Coil

Re: F70 Settings
Posted by: REVIER
Date: December 29, 2015 08:14PM
0 disc will give you a lot of chatter, even turning it to 1 quiets it down a lot.
I never hunt on 0 and don't worry much about losing depth with the sense set low, either.
Supposedly this thing does not lose much depth at all as you turn the disc up unlike other brands and models.
I have run it from 1-65 and don't notice much difference.
Anything under 5 or over 20 gives a slight boost in sensitivity but also chatter, sometimes.
SL will get deeper than DE, but it will open you up to more chatter, also.
You might not realize how deep this thing will actually get in decent soil on lower settings...don't assume you know until you play with it more and see for yourself.
I have experimented a ton and some settings are deeper than others but the kind of soil has a lot to do with depth, EMI might too, everywhere is slightly different, don't assume you know about depth till you spend more time digging in your soil.
I am not saying you will hit the same deep areas on all settings but there are technical things you don't yet know about.
The sense range is not what you might think it is.
Startup 60 is not 2/3 power, 50 is not 50%, 33 is not one third and so on so turning it down some to hunt quieter, if that is how you want to do it, you might get deeper then you might believe.
There is a relationship between the sense and thresh settings, start at factory levels and adjust higher from there.
It has been described as sense is power, thresh is the raw signal before processing, or, the thresh setting is like opening a door.
High positive you hear everything big and small, as you turn it down the door closes and the more it does the more the smaller targets cut out.
I can still hit coin targets pretty deep on -4 so far and it is pretty quiet.
I learned to hunt with pretty high settings, just got used to it, chatter doesn't bother me and when the coil moves over a target it calms down and tells you, anyway.
If you can believe it I found that all metal, sense and thresh maxed out and SL speed gets me not only the deepest but it does give me some of the best, clearest and best ID's on signals and is actually less bouncy and battery than using disc.
Still noisy for sure, but less noisy than you might think compared to using disc and my go to settings in heavy iron situations and on program 2 as a check for most deep signals.
It took hours to use and understand what I was seeing and hearing using these "blast through" settings...well worth the time spent to me.

Spend time on factory or lower settings and DE.
Get used to it then start turning it up.
You have time, the thing will find almost anything both shallow and deep as you learn.

"What if doing the Hokey Pokey really IS what it's all about?”
F70, F2, Compadre, Mojave, Judge2 - 2018....Mostly just some clad so far...more to come!

Edited 3 time(s). Last edit at 12/29/2015 08:38PM by REVIER.

Re: F70 Settings
Posted by: still looking 52
Date: December 29, 2015 08:22PM
Most high end machines like yours has a factory default setting and for beginners this is a good place to start. After that you can start playing around with the other settings. I'm not what you would call an expert but a couple of basic things is the higher the sensitivity the greater the depth and a lot of us run that as high as possible until the rigg starts to chatter and then just back down from there. Disc settings doesn't seem to affect depth that much and threshold settings is not a big factor on depth either. Maybe Revier can give you some more help if he reads your post.

Re: F70 Settings
Posted by: MarkCZ
Date: December 30, 2015 12:36AM
I'll throw in my 2 cents on the threshold, or another understanding of it.

Detectors of OLD, the 1980's and early 90's the threshold was a manual adjustment that you dialed up an audible sound (tone) just to the point that you could hear it and it was that level that was your "Operation Tone".

Well, moving through time and into the next realm of electronics the threshold become a bit more confusing for us old timers because many of the newer units are commonly termed "Silent Search" detectors, but the term "Threshold" is still used, now if that isn't a head scratcher :stars:

Old school threshold was usually a nice low constant tone.

New school threshold, isn't that ALL!
The detectors are silent search below the threshold setting of "0" and that's not to say that your not going to hear beeps and chirps, but what your not going to hear is what is called "Detector Noise" this is the noise of the electronic circuits of the detector. With the newer units if you set a threshold higher than "0" you leave the realm of silent search and inter into the range of "Detector Noise" but its not a nice tone, its just electronic noise, clicks, ticks, and static that confuses the operator. Running a newer detector into the "noise range" is best left for veteran users of these types of detectors, other wise we get lost between faint targets and the noise.

Now, that covers what is above a "0" threshold, but what about below "0" or minus "0" (-1__-2___or -6 and so on).
I like to use the term "Trigger" or "Gate" when talking about modern threshold, and its still in the audio department. Think of it like this, the audio amp sends a report (an alarm) to the operator when something comes through the detection circuit, well the threshold has an adjustable trigger (gate) for the audio amp to either "Except" a response and pass it on to the operator or, "Reject" it and ignore it.

At "0" the audio amp is set to its most 'Sensitive' level and still remain silent search. Well, at "0" the audio amp is very jumpy much like a hair trigger on a firearm, any little thing will trigger an audio report, the slightest tick, any form of EMI, and you'll hear it. (I'm thinking stability, or lack of it)
Now, its good that we have control over the threshold and we can dial it down, the higher the minus number of the threshold setting the stiffer the trigger is for the audio amp, a minus -8 is going to take more signal input for the audio amp to except and send the report to the operator than a -3 setting.

Okay, now lets add in the "Sensitivity" it sounds much like the threshold and it is, except its not adjusting the except or reject range of the audio amp (actually pre-amp). Sensitivity is on the other side of the electronics, that is the detection circuit. In basic terms as you crank the sensitivity up the detection circuits become more sensitive to smaller and or fainter targets. Now that's just basic! because with a lot of the newer upper end models the manufactures has incorporated other aspects into the sensitivity control.

There isn't any reason to run your sensitivity @ max and your threshold @ -9 (minus 9) or vise-versa a "0" threshold and a sensitivity @ 2 you would be countering the effects one control with the other.
Lets take clad stabbing, surface hunting a fairground for fresh drop coins,
You don't need any depth,
You don't need any clicks, ticks, or other faint audio responses.
So, you could use a sensitivity of lets say 20 and a threshold of -6 or maybe even -7 (with smaller coils you may want to raise these number a bit) notice that both the sensitivity and the threshold went down! these settings could be referred to as Mild settings, but it should be very stable and perfect for the job at hand, "clad Stabbing"

Now, lets say someone you know lost something smaller than a US dime (or other small coin), its a fresh drop, but its smaller than average coins, so you may need to turn up the sensitivity a tad for the detection circuit to pick it up, but the threshold may be fine because its small and its close to the coil it would still gate the audio pre-amp. (still mild setting)

Now, lets go hunt some deeper older coins!
This is going to take some hotter settings, which normally will be as HOT as you can run the detector which is more often than not limited by stability!!
You know you don't want to miss a faint signal, so the threshold is going to need to be set closer to "0" and the sensitivity is going to need to be turned up. On my F70 and my area I've found that with the 11" DD coil my MAX (HOT) settings are,
Sensitivity @ 70
Threshold @ -2
if I get a lot of little ticks and pops I will most likely drop the threshold down a number or two (-3 or -4) to stiffen the trigger for the audio pre-amp. Now if I'm getting stronger false type signals I would probably lower the sensitivity down to maybe 50 or 60 and bring the threshold back up to the -2.
The point is that I never make a wide swing between these two controls, I may move one a little, if the detector still isn't stable then I will bring the other control down a bit.

Hope this helps!


Avatar, Me and my two brothers from left to right!

WV62 - MarkCZ - Still Looking 52

Edited 1 time(s). Last edit at 12/30/2015 12:39AM by MarkCZ.

Re: F70 Settings
Posted by: big-ears
Date: December 30, 2015 07:32AM

I think that is the clearest, most concise, interpretation of the F70 controls I have ever heard! Thank you................

Re: F70 Settings
Posted by: fjs440
Date: December 30, 2015 07:44AM
You guys are impressive. That information is what I am looking for.

Re: F70 Settings
Posted by: MarkCZ
Date: December 30, 2015 10:53AM
"big-ears" & "fjs440" you're most welcome!

I'll be surprised if my post doesn't stir up a debate LoL there is WAY more technical terms that are used, but for us normal users its the tech stuff that zooms right over our heads (well my head anyway)

HAPPY NEW Everybody!


Re: F70 Settings
Posted by: still looking 52
Date: December 30, 2015 12:45PM
Man it's nice to have a little brother like Cz5. That's an excellent explanation on those settings. I'm thinking you nailed that one little brother. That's going to help a lot of people with their detectors to this coming year. THAT'S OFF THE CHARTS!

Re: F70 Settings
Posted by: MarkCZ
Date: December 30, 2015 02:50PM
"big-ears" & "fjs440" you're most welcome!

I'll be surprised if my post doesn't stir up a debate LoL there is WAY more technical terms that are used, but for us normal users its the tech stuff that zooms right over our heads (well my head anyway)

Fixing a type-O, I find them even in my little post.



Re: F70 Settings
Posted by: WV62
Date: December 31, 2015 10:02AM
First things first, learn how to do the factory reset, I think it is on page 9 of your manual. This will clear all the settings that may cause your detector to act up. I have seen a lot of post where guys are about ready to send there machines back for repairs, and somebody will tell them to do a factory reset and their detector is fixed.

Looks like the above post got most of the middle.

Last things last, I would suggest not messing with notches until you got all the other settings figured out. When you get around to playing with notches I would strongly suggest a factory reset after you are done. Setting notches seems to be where a lot of new users set something and don't get it cleared out. I have been using a F75 since 2007 and just about every hunt I start with a factory reset, which makes me set the machine up for the days hunt.

Nothing said here is a must do, just a heads up.

Ron WV

Worked and lived in the Huntington West Virginia area all my life, retired 2010
US Air Force Vietnam Veteran (68-69 & 70-71)
Started getting into metal detecting around 1975

Re: F70 Settings
Posted by: mvd
Date: January 08, 2016 02:37PM
What an awesome description on the threshold. Thanks so much!! It does help to understand especially for the guys who have spent most of their time with older units.

Fisher 1260x (1988 to 2013)
Fisher F70 11 DD (2013 to present)
Fisher 1280x Aquanot 8" (2016 to present)

Re: F70 Settings
Posted by: drittless
Date: January 08, 2016 08:24PM
Thank-you MarkCZ and others. Although I had to read the post several times, I think I'll actually remember those functions now. So when you ground balance, are you sort of setting a quiet baseline to begin from? Will changing frequency help with that? Frequency doesn't get discussed often, maybe it's not a big deal? I'm a slow learner I guess.

Re: F70 Settings
Posted by: MarkCZ
Date: January 08, 2016 09:06PM

This is more of a 'Shift' and not a channel change.
It has a couple of primary uses,
If your hunting in close proximity to another hunter using a detector on the same frequency you have the option of a 'Frequency Shift' to reduce detector "Cross Talk". (such as club hunts)
It can also help in certain types of EMI to increase stability by shifting the frequency in one direction or another.

"Ground Balance"
It sets the internal circuitry to ignore minerals in the soil, in other words, to better deal with the effects of ground mineralization.


Re: F70 Settings
Posted by: drittless
Date: January 09, 2016 09:12AM
Does frozen ground effect ground balance? I would assume you guys get tired of addressing these questions. Have any of you considered offering real time field seminars for small groups? I'd love to spend a few days actually using my F 70 under different conditions to learn this machine. Would be even better during my Minnesota winter if it someplace above freezing. Then I think about how much fun I have just swinging around sporting fields with my Delta and wonder why I have the need for better technology at all. I leave my cell phone in the car................

Re: F70 Settings
Posted by: MarkCZ
Date: January 09, 2016 11:55AM
I do find that certain conditions (changes in the environment) will effect ground balance even at the same location,
Long hot dog days of summer is the worse, I'll start out in the early morning with one ground balance setting (lower) and then by noon I'll have to re-balance. Over the years I've concluded that this is due to much higher amounts of "Solar Radiation" charging both the atmosphere and ground minerals.
The reverse of that is,
Early morning, (or at night)
Cooler days and more moist (damp) soil will tend to lower the ground balance numbers.


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