Question about depth accuracy in pinpoint mode

[Ronstar]

Quick Q? For the F75 crowd. I’ve noticed now that when pinpointing a solid target the depth indication is off. Its saying basically 2” deeper than it really is. Also, this morning it rained here lightly. As long as I kept the coil just off the cut grass height I could get a depth reading but if I pushed down gently hit dirt level the screen went blank, as if shorted out. This doesn’t happen every time and no idea if the wet grass is cause. Is this normal or should I contact Fisher?

 

[REVIER]

Many report depth can be off on this platform on many detectors...on my F70 it is pretty darn accurate but I consider that just luck.
Most just learn to deal with it.

The other thing is not normal, not in grass or anywhere else wet or dry.
However, if there is a target at the very edge of the coil's scanning range this behavior is completely normal.
You might get tones but the screen has no VDI numbers which is why most owners think tones are more important in this one than screen info.
I don't really know for sure but I can see a situation where if you are scanning a shallow target with a deeper target underneath as you lower down that coil it could possibly behave as you described.
I have never seen this happen with mine, never heard of this happen to anyone else, either...you say it doesn't happen often so how many times has it happened to you?
Try reducing sense if you notice this again and see what happens.

 

[still looking 52]

Everybody says the F75 reads about one to two inches deeper than actual.

 

[Ronstar]

Owners book says set coil aside from target and then come back over it in pinpoint mode. I can see this as once centered the squeal is at its peak. Then I would come straight down over it to get the depth. My Garrett Pro-pointer will normally vibrate if target is 3” or less in the ground, depth on the read was 4-5” yet pointer was sounding. I had one good horizontal quarter that measured 3.5” down and readout was 6”.
As far as the going blank incident, it did it twice this morning on relatively shallow targets. Any downward pressure onto the grass just went blank. The F5 would do that sometimes if the coil was literally on top of the target....... Sensitivity is at default which is 80 I believe but I can try that if happens again.
Thx

 

[REVIER]

So you hover over the target to pinpoint and then drop the coil down to the surface to read the depth?
Sounds weird and unnecessary and can be causing this issue..
Just try keeping the coil on the ground as you move the coil over the target from about 8" away and read the depth at the loudest tone when the little mark on top of the coil is over the target center.
That's all I ever did and always got pretty accurate depth readings and no blanking.

 

[Ronstar]

Hard to articulate.... book says to move off to the side and then cone back over the target. It works pretty well..... now I might be flipping switch forward as not used to it yet. I dont think I am but I caught myself once and have been thinking about that since

 

[WV62]

When Pin Pointing I would suggest you Pin point the target first. I swing my coil to the side and up then pull the trigger. Once you got the target pretty much under the coil I for one like to de-tone (Narrow It Down) the pin point. What that is once the target is under coil let off the trigger with the coil on the ground and pull the trigger again now you have detuned the detector and you will be able to more center the target under the coil. Sometimes I do that detuning a couple of times if needed. This is explained on page 24 of the manual and it is titled Narrow It Down.
The way I get along with screwed up depth reading saying it is deeper than it really is, It is saying it won't be any deeper than the number it gives you for a coin. It is messed up and mine has been back to the factory 2 times with that item on my list of things that needed attention. I could tell they worked on it but it was still off. My brother SL52 posting above bust my bubble a lot of times when I call him over to check a good target with his F5. I tell him it is on the high side of 6" and he says how about 4" and a clad dime rolls out. LOL
Now for that blanking problem that sounds like a coil problem, so I would change coils and see it still does it. I have been running the F75 since 2010 and that doesn't sound like anything I have experienced. You shouldn't have to baby that push down on the grass, it could be a wire moving a little and not making connection or it could be water. To check for leaks just stick it in 5 or 6 inches of water, you may trash the coil but it is stated to be water proof. No need to mess with it for a couple of years just to find out you got a leak in the coil.

Good luck,
Ron in WV

 

[jim tn]

Ron is right about your coil situation. It shouldn't be doing that. I've never experienced it anyway, either. And yeah, the depth gauge is off. After a decade of F75 use myself, I got used to it years ago. HH jim tn

 

[Ronstar]

Thanks for the tips! I cant get back out until Sunday so will try those.......

 

[Ronstar]

Just got to the manual and you are correct! I totally misunderstood what Narrow it Down was saying!!!! Back to the fields .....,.

 

[Ronstar]

Ok, was out for awhile in my pasture and tried the narrowing down. Found a good signal a few inches down. Moved coil slightly off center, released trigger and pulled again. Nothing, no sound, no nothing. Tried moving the coil around and over where target was and still nothing (yes I was pulling trigger towards me). Pulled away and reapproached and found target again. Pulled coil slightly off center, released, pulled again, nothing. Am I doing this wrong? Its what the manual says to do.

 

[REVIER]

Slightly off center won't work.
If you get a target move the coil 8-12" away...keep the coil on the ground.
Hit the trigger to turn on the pinpoint feature then slide the coil, keeping it in the ground, toward target center.
Listen to the tone for the loudest, watch the numbers for the lowest.
To detune and narrow things down even more release the trigger, move the coil out a few inches where target center is at least a little past the edge of the coil then hit the trigger again and move coil back to target center.

Do you use a pinpointer, have you used that to detune in the past?
Same thing will happen, if you detune too close to the target it just knocks it out completely...makes it go silent and invisible.
You need to learn to do all this at the correct distances and then you should be all right.

 

[Ronstar]

I think this morning I may have done that. I was out on the ball fields and hit an odd high tone that was only hitting one way. Was trying everything I could to narrow or detune with the pinpointer getting narrower. The once I got it to come back on it was just a small area and 8”. I dug and dead center was this pin at a 45degree angle! Im getting the hang of it......

 

[REVIER]

I think this morning I may have done that. I was out on the ball fields and hit an odd high tone that was only hitting one way. Was trying everything I could to narrow or detune with the pinpointer getting narrower. The once I got it to come back on it was just a small area and 8”. I dug and dead center was this pin at a 45degree angle! Im getting the hang of it......

Coool....a soccer pin in great shape.
You are doing well.

That pic brings me back.
We were two weeks away from leaving Kansas and were moving back to Bama and I found a huge soccer complex I had not hunted before.
The first day I was out digging in the side of one field, there were about 15-20 at this huge place, and the head groundskeeper came up to me and said no digging there.
I smiled, introduced myself and shook his head and innocently asked why not?
He told me recently in the past they caught a guy digging up the playfields, leaving holes and trash all around and they kicked him out and told him not to come back again plus they chased a few others away since.
I shook my head and said that guy was a jerk, there was no need to even go on the field because there was much more around the field where the spectators stood, sat and watched the matches.
I told him I dug very little holes, cover them up well and took all my trash and he asked me to show him.
I swung, got a signal, dug a small hole and recovered a coin and covered the hole like I was never there and he was satisfied.
He said as long as I stayed off the field I was good to go
I only had limited time to hunt because we were leaving town soon but I made the best of the eight hunts I had and man I found a ton.
Many, many pins like yours, official flipping coins and half dollars also used as flipping coins, silver rings and pins and a ton of clad.
So much clad I made a goal to dig at least $70 worth because we were going to the casino one last time before we left and $70 was what it was gonna cost us for a special lobster buffet we planned on visiting.
I came close...a little over $60 in 8 hunts.
I never considered myself a mega clad hunter but at this site anyone could do it because there was so much.
What I didn't find was gold, if you think you are frustrated at your site imagine what I went through seeing what was here, pretty much virgin ground, tons of targets, silver for sure, a nice tri-metal bracelet, a bunch of other stuff but not one gold ring.
I am positive there was gold there, probably a lot of it, but I just ran out of time to continue my hunts to actually find any.
If I was still living there I probably would still be hunting there...and I would have found good by now.
Good times...good times.

 

[Ronstar]

Those are definitely some cool finds. At this point in time I have more 925 pendants than pins. Not real sure what the soccer pin is made of but it preserved itself pretty well underground! The pin spike was corroded off but the brass like metal and I assume porcelain face were near perfect. Surprised there are not more found as numerous summer camps etc held every year except this year.

 

[amcoins44]

I asked this same question here when I got my F75 2 years ago. Mine also reads 2" deeper than actual. Just a quirk of the machine, but irritating.

 

[Ronstar]

Ok, have a few hours under my belt now. Have been trying all the tips provided and (gasp) played a bit with the programs.
Still not totally getting the narrowing down portion of pinpointing but at least target is in the plug/channel I dig. Depth is constant 2” less than being shown so just need to remember 4” is the new 2” and thats essentially a surface recovery.
I’ve been leaving it in DE mode and getting clad and junk jewelry 2” to 8” pretty consistently. Today I played a bit with JE and noticed not as quiet but still very comfortable to listen. Hit a solid dime 70 signal at 7” in the tot lot (I was only scanning the wood chip playground) so carefully pulled the loose chips out to that level. Garrett pinpointer sounding off at bottom but no coin. Dug an inch deeper and target gone. Started in on excavated pile and pointer screaming I was on it? After about two minutes I spotted a very small flower shaped object and bingo! Not a pin, not an earring, no idea but its a red flower with a brass colored metal construction. Manual says will pick out smaller objects and thats confirmed. Hit was solid in the headphones.
Then I hit a sound I’ve not heard before. If you think elk bugle and at the end they kinda go “eyonk” a couple times, thats the sound. Only one way sound, not two way or four way. It was not super strong and pinpointer showed 12” (so 10”) so it was below chip level and into base dirt, didnt try to dig. Had it once on pinpointer but unable to do it second time (hit was consistent tho).
Getting more comfortable and need to play with other programs......... Have not tried All Metal Mode as of yet......

 

[Rob in (Ca)]

Pinpoint mode is to time consuming.........I just do the pull Back wiggle in disc mode......when the Target tone stops .....its in front of the coil ........takes like 10 seconds .........after digging 1000”s Targets with the F75 ..... I can tell the approximate depth by the tone ......that’s one thing I really like about the f75 ....very fast and productive detector.

 

[WV62]

One thing for sure other people have different ways of pin pointing, try them all and just see what you like best. I would suggest doing your testing on a throw down coin so you know what your are dealing with. If you do it out in the real world of detecting it will take longer to master it because of variables, coins on angle, something close to your target that pulls you off. Just keep it under control when learning. De-tuning is kind like breathing you do it without thinking, If you do it just like the book says you will be there all day trying to center the target. Just take your best guess on the first pull of the trigger and then just pump the trigger and narrow it down. If you keep pulling the coil off to the side it will not narrow it down. Now sometimes if you nail the target dead center your target will disappear so you will need to move the coil a little and start over.
I have been doing this since the 70's and some of older machines called it de-tuning and the newer Fisher F75 calls it narrow it down, so when I got my F75 in 2010 I didn't have any problems with the narrow it down pin pointing.
Just throw a dime down and work with it a few minutes and you will be off and running. It is a little detail but gets bigger as you get out on a real hunt. Just get the feel for it and you will not think about it, just breath.
Ron in WV

 

[jim tn]

Ron's method is the way I have been pin pointing since back in the 70's, as well. A good pin point will give a more accurate depth reading, too. It will still be off on the 75, but not as much. One will also get a more accurate target i d, and even tone i d. HH jim tn