f70 chatter "freqed-out"

[closerbaby]

Hello all from Colorado, Just got an f70 and wow this thing has the high heat. Very impressed with the depth of this thing but did run into the chatter folks talk about. After playing with the sens and thres tryin to get it calmed I started to get worried...then I remembered the freq shift and low and behold it smoothed right out. Does anyone know what the frequency shift does to operating freq, in manual it states 13khz and that I assume is at (f4) which is factory default, but I lowered it to (f1) to get chattered gone and want to know what frequency that this machine is now operating on...Any help with this new detector would be greatly appreciated...Thanks again,Gary

 

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[Sandman]

Doesn't help to know what actual freq it is using so long as you can dial it in for good operation.

 

[steve1357]

I'm still using my old F5 in all metal, I can't get any confidence in my new F70. I can't get it to quieten down in all metal mode, I find myself making repeated swings and getting random hits, it seems by varying how close the coil is to the ground.

I can manually ground balance the F5 but this auto wishing ground grab on the F70 isn't working for me. Using the pinpointer tells me I'm not getting it right, which is one problem I think for the chatty F70.

By the time I set the F70 sensitivity at 35 in SL mode and threshhold at -9, I've invested a lot of money for no improvement.

 

[closerbaby]

hi Steve and congratulations on the new f70.. I totally understand your fear of it being chatty so let's try and figure this machine out. first of all which coil are you using?.. make sure you're coil connection and your head connection are nice and snug. The f70 is a very hot machine... lightning fast recovery speed and you can't swing like older or even other detectors except the f75... where you locate target you need to use deliberate shoulder to shoulder swings...rather quickly... ground balance is important and majorly important in auto tune mode.....I use program 1 with discrimination set at 8 ( still seems to hit on small gold rings) ,dp,sens about 75,thres -3,3h tones,no notch.....program 2 autotune,sl speed,Sens up to 80-84,thres -2, ..... but you need to make sure your ground balance is done well...use pinpoint to find a clear place..... then I hunt in program 2
and switch back and forth with target seems to be located... machine is a little hard to learn but it is worth it when you finally dial in your right settings...this is a very capable detector.... good luck,gary

 

[steve1357]

Thanks for your help Gary. I refuse to give up, I hope we can figure out what I'm doing wrong.

I started with ground balancing it this evening. I can balance it by the book, I easily get a steady two digit number that doesn't change. My yard usually ground balance from 58 to 62. Problem is, if I raise the coil or lower it, I can "push" and "pull" tones which leads me to think it isn't ground balanced properly. When I ground balance my F5, it's pretty steady from ground to a foot above. I can manually dial in ground balance on the F5 to where I can't pull or push a tone.

My first question is, is your detector "quiet" while running AT mode, SL speed until you come across an object? I have to turn sensitivity and threshhold down so far on the F70 to be able to use it, the detector is worthless. It's acting like it's hitting targets when I sweep it slow, but none repeat like a target should. The ground is uneven, it's like it thinks changes in elevation is being viewed as a target based on the mineralization is changing as I sweep? I'll try some other things, there has to be a pattern somewhere to be found. I gave up today when after ground balancing, and getting a noisy sweep, I pointed the F70 up in the air and it still wouldn't shut up.

I have three coils, the 11DD, the 10 and a 5", all new from Fisher for the F70/F75. I used the 11 and 5 today, same symptoms.

My first mistake was not reading the manual close enough. If you go to Kellyco's website and pull up the detector comparison screen, it shows the F70 ground balance as fixed=no, manual=yes, automatic=yes. This led me to believe I could manually adjust the ground balance.

Thanks Gary

 

[IBdiggin]

Hi Steve. I know exactly what you are going through. I struggled trying to decide between the F5 and F70 for quite some time. Then when I stopped to pick the mind of a local dealer. He sold me an F70 like new for $30 more than the F5 and included a cheap pair of headphones. He also swings an F70 so I have a confidence builder on my side with pointers on adjustments. Said a friend of his just could not get the learning curve of the F70 and had it on consignment so his loss was my gain. Many times I asked myself just why the heck did I buy this thing over the F5 especially after reading the Bible of the F5 by the guru Mike Hillis. But like you I was determined and I new from other readings that the F70 was no toy and very capable and needed to be tamed. I was wrong, the F70 has a mind of it's own and you don't tame it, you learn it. I use autotones set up in mode 1 for ground balancing. Always. I also go back and forth between mode 1 and 2 sometime to check to see if a certain tone came from falsing iron below my discrimination settings in mode 2. Those tones will now come to me in autotone. If no iron tones are there and falseing in fact was coming from tabs or foil then you should see a jumpy VDI number. After a while you will learn the clearity in the signal and know immediately unless your trying to pick a good signal out of surrounding trash. I have autotune set up in my program 1 mode with 65 sensitivity and 0 threshold. After ground balancing I use a trick of Mikes to check to see if balance is neutral by pushing pinpoint and checking the display. You should see two horizontal lines if it is balanced while coil setting flat on the ground. With that sensitivity and threshold settings you will still get a mild groan if hunting in autotune. The spikes you get in tones are due to its extreme sensitivity to ground minerals and by watching the VDi, dirt, and confidence meters you can determine if the tone is a true signal or ground noise. If you need to change frequencies because of EMI, you will need to rebalance. I set my program 2 with about 0 to 6 discrimination with 65 sensitivity 0 threshold, default speed, delta tones with nothing notched out. The more discrimination you use, the more false signals you will get unless you turn sensitivity and or threshold way down in the trash. I don't care to do that because I can still hear those 8" quarters set up this way. Many signals that sound chirpy or sort of fuzzy and jump around are falsing from iron or other trash signals. Training your ears is a very big step in learning how the F70 works. Learn which signals to ignore. True tones are very clean and can be heard swinging in all directions unless the target is nearly out of the detectors range. I don't have a DD coil so I do all my work with the 10" concentric. I like the cone shape of the concentric at since I can raise it higher to use the point to sort out multiple signals that may be masking. Response is so fast on the F70 that multiples can many times be determined without a sniper coil although I am sure they definitely have their place. It took a while to get used delta tones but if using low discrimination you have a different tone for each different metal. I am sure others can tell you more than I since I've only had mine for 3 months but this is what seems to work for me so far. Hope this helps a little and don't give up on the F70. ---------Larry

 

[steve1357]

Thanks Larry. I've printed yours and Garys settings. I'll document how it goes and post it in a few days.

My first wrong assumption is thinking the F70 should be quiet in autotune SL mode. My F5 is quiet running 0 to -1 threshold in all metal digging deep.

I'll use the 10" coil like yours for consistency.

 

[steve1357]

I'm making progress Larry. All metal mode is pretty good now when I turned it down to 65 sensitivity and -4 on threshhold.
I was use to my F5 where metal hum starts at +1 and it's pretty quiet at 0 and silent at -1.

The technique of using program 1 for all metal and program 2 for discriminator is working great for me testing things out. My tests I was using the 10" coil....

I live on a pretty good hill, lot of sandstone and iron rich clay I think. A friend showed me some samples of sandstone rocks they found a few miles away that literally look like foot long 4-6" diameter pieces of pipe. I can't remember what he called the formations, but I noticed some broken pieces in my yard which I thought might have just been deposits of sandstone as something like a root decomposed and was replaced by this clay/sandstone. What I'm getting at, I usually run 57-59 in my yard for ground balance. After slowing down and checking ground balance very often, I was discovering some of that noise was the F70 going off on "mineralization" changes. The F5 wouldn't bark at me like the F70 does in the same place. I would ground balance at 59 and less than three feet away would be 66 or 67. During the sweep, the F70 would let me know! Is it that sensitive? Awesome, I'll just have to learn it as you and Gary said.

DE mode is quiet but the depth loss from SL is noticeable. Question, how slow should you swing in SL? Three feet wide and take 1001purple elephants to make one motion? Two feet shoulder width?

I do need to watch the raising of the coil on each end of the sweep, that's when I discovered the mineralization changes. If I keep it ground balanced and keep it 1-3" off the ground during a sweep, it's good for me. When I started getting sloppy in swings and fast, that's when I was getting frustrated earlier leading to my first post.

 

[IBdiggin]

Hi Steve, Glad to hear your starting to get comfortable with the picky little quirks of the F70. Many people won't put up with them and therefore hate the F70. I on the other hand, I find it to be challenging and rewarding and sort of a game in learning it and enjoy doing so. I have the patience of stone. The people who designed the F70 this way, did so for a reason and it's up to the user to figure out what it will do. Like I said before, you do not tame it, you let it be it's glorious self and just learn it's language and hang on. Let it teach you what the people who created it intended it to be. I can't help with the slow setting as I use only default at this time as I do get pretty good depth in my type soil here and have lots of trash. Also I like the quick recovery of the default setting. When I get some of the trash cleaned out of the areas I hunt, then maybe I will set it up in the slow mode. I think I will try a DD 5x8 instead of a sniper first. High 70's and low 80's are what I usually balance at. They stay pretty stable and only change when going from sand to sod at the parks or wet sand to dry sand at the fresh water beaches here in Wi. I am using autotone mode less all the time as I am getting better at hearing the chirps and fuzziness for lack of a better word of the false signals. The foil seal on the tops of little milk bottles and other drinks that are round, and ring out a solid 20 to 22 in tabs are very good practice in hearing what a small lady's gold ring might sound like. Very stable and clear in all directions and do not cause any false signals as coins. If there are more tab signals generated by a different source in the same target area you still can pick them out if you go slow. As for swing speed, I cover about 6 feet in my swing width and take very short steps so I only advance about 6" with each step. I usually get a count of one thousand one, thousand two in each swing. I have to admit that in default with a sensitivity of 65 and threshold of 0 in disc. mode of 6 , I will probably run out of depth on quarters at between 8 and 9" in sand so wet that there is water standing in the hole when you find it. I once heard what Mike Hillis referred to as whispers from the deep in the quarter range but only in one direction. Well I was sure that it must have been a false signal from iron but the clarity of the signal kept haunting me until I had to go back because the VDI didn't jump around like falsing. I switched to autotone and did a fresh ground balance as there is lots of iron in the Wi. River. I increased sensitivity to 75 in autotones and got a very definite groan but with no VDI at all. I turned 90 degrees and got exactly the same thing. So I dug and at about the depth of 9" I pulled out a clad quarter with no idea how it got that deep. That was the day I learned to do a backup check of iffy signals in autotones and probably use it more for that and ground balancing than actually hunting. I can't state enough how important it is to learn to hear the chirpy fuzzy sounds that sound like they begin with a ch. HH and don't give up on that 70-------Larry

 

[steve1357]

On no Larry, you got to try the SL mode. I don't know how to describe it, maybe it's that new boost thingy they added to the F75. Adds two to four inches? It's so much, I don't like to run DE.

Then again, if you're going to run SL, bring a shovel. I'll run DE when I get lazy.

SL will be noisier, a good issue I was having.

 

[IBdiggin]

Sounds interesting, I'll give it a try when I get into some of the heavily hunted areas of the river shorelines that are considered party spots. Usually I hit these frequently so as to beat the competition at the latest drops so there is some possibility there is some deep stuff I may find that someone else including myself has missed. After finding a 1980's clad quarter at 9", I got a little discouraged when wondering if I would ever find any silver in spots like these. Do you notice a slower recovery in SL mode as compared to default? If so I would think that would make it harder to pick a clean deep target out of a trashy area. Another good reason to dig everything---Later

 

[steve1357]

Try it out in your garden with some trash if you can. I've got a clad quarter at 10" that my other detectors don't know is there. The F70 on DE and all metal doesn't, not a peep. But put it on SL and go slower, you get a solid zip going across it both directions. Even SL mode running discrimination will chirp a little.

It is a slower recovery like you think and would be difficult in a target rich environment. I do like SL with the 5" coil though...

Have a good weekend and thanks again Larry.

 

[steve1357]

Larry,
I found the engineer talking about the SL process on the F70.

File: processes FAQ 29 Oct 09 DEJ

 

[IBdiggin]

Hey thanks Steve. Always enjoy readings of Dave as well as those hobbyists who seem to have mastered their machines. I clicked on more of Dave's articles at the top of the link you submitted and found some more very interesting stuff. I feel these great articles greatly benefit those learning to master the products that fisher puts out.---Later

 

[steve1357]

Got an observation that supports my guess that the F70 is sounding off on small changes in mineralization for me.

I ground balance at 58. I have a quarter at 10" that the F70 will go off on running SL. I decided to ground balance on top of the quarter. It says 52.
A shallower quarter shows ground balance of 25.

So with parts of my yard ranging from 58 to 71 I saw today, no wonder the F70 yaps at me a lot just swinging the coil across the yard...

The F70 is as hot as you want it, going off on small changes of mineralization as I was seeing initially, explains me getting frustrated with the ground balance issues in my particular soil.

(and yes, that's how metal detectors are suppose to work, changes in the field)

 

[IBdiggin]

Absolutely, ground noise is ever apparent in autotone mode and any other tone that is too weak to assign a VDi will show as ground. And equally apparent in discrimination mode but in the form of false signals. This morning I went for a 2 hour hunt to clean a little more trash out of this Tiki bar that I pound every Monday morning in the summer by the lake. I have been running 0 discrimination lately if the iron isn't to heavy and was really surprised to see a lot less false signals. Also have been learning delta tones which seems to help assign a different tone to all signal types. F70 totally blew my mind again today when I came upon a jumpy 38 to 45 tab mixed with a solid 20-21 foil tab hiding a 38 nickel signal. The signals were all within about 10" width area. I first pulled a beaver tail at 1", then a 21 VDI foil seal, about 5" away which sounded like a ladies gold ring. The latter I have yet to find but have heard digger 27 describe it enough times to know that is what it would sound like. That was at 3" deep. Then after the tab, I could hear what wanted to be a nickel signal real close to the foil top seal. You know the perfectly round ones? Still confused me cause I thought it was jumpy foil till I raised a little with the concentric and the nickel came shining through and a big smile came to me cause I knew I had just unraveled a total mess and learned I now knew how to find gold rings in trash. It was the delta tones that give them away as the difference in the tabs and foil each had their own tone as well as the nickel. Sadly no gold but I did get a clad nickel and the knowledge. The nickel was at 5" about 4" away from the foil------Love thy F70 -----Later

 

[steve1357]

I'm surprised at the difference I get between the stock 10" coil and the 11"DD coil. With the difference between DE and SL modes and the two coils, this F70 is something else. Wish I had an F75/T2 to compare.

I have a F2, F5, and F70, three completely different levels of depth.

 

[IBdiggin]

Ok, now I'm curious. Do you like both coils for their own abilities or do you have a one over the other preference? I still have only the 10" concentric. I am still trying to decide if the F70 is enough like the F5 to consider Mike H. recommendation of the 5"x8" DD he refers to in his writings about the F5. I did find a nice clean volleyball court yesterday and was able to run in sl mode at a mildly chatty sensitivity of 75 and 0 disc. and 0 threshold. WOW, I was impressed with the increase of depth. No bling but over $5.oo in clad.----HH

 

[ivan salis]

different soil conditions( and the minerals contained in it ) are more friendly to some freq than others * if one freq does like it try another

 

[steve1357]

Ok, now I'm curious. Do you like both coils for their own abilities or do you have a one over the other preference? I still have only the 10" concentric. I am still trying to decide if the F70 is enough like the F5 to consider Mike H. recommendation of the 5"x8" DD he refers to in his writings about the F5. I did find a nice clean volleyball court yesterday and was able to run in sl mode at a mildly chatty sensitivity of 75 and 0 disc. and 0 threshold. WOW, I was impressed with the increase of depth. No bling but over $5.oo in clad.----HH

Been busy this week, will answer this weekend Larry. But where do you see a 5x8 coil for the F70? The F5 coils won't work.