Bottlecap blues- and other ferrous- can anyone help?

[Chris(SoCenWI)]

Hello all,

I'm a long time(6 years) Explorer XS user.

Recently purchased an F-75 and have been swinging it quite a bit in the last few weeks. I haven't done enough head to head testing to see if there are situations where one machine will simply not see what the other can see, but it seems to to me like there are times the F-75 can pick up a coin in trash that I missed with the explorer.

If I were more disciplined I would fire up the other detector and go over the signal before I dug it, but for now too much work. I'm convinced that there are many more coins hiding in trashy areas. I think the explorers did a great job of making old sites productive again, but they are certainly slower responding units. I am curious to see if the faster f-75 can find even more in the trash; so far a qualified "yes".

BUT.

I sure am having difficulties with bottlecaps and other ferrous round shaped trash. They are IDing anywhere from nickel range to zinc to quarter and seem to repeat strongly and consistently. I've dug several coins that were much worse signals. Anything to look for to help differentiate?

In all my thousands of hours with the explorer I don't know if I ever dug a bottle cap. The explorers will often hit good on big iron and rusty square nails, but with the two axis display you usually have a pretty good idea that it might be iron falsing.

The F-75 seems to also hit strongly on deep big iron, so far square nails have not been a problem. But I have not found any audio/display clues to when I am over iron/bottlecap as opposed to a coin.

Any help would be appreciated.

Chris

 

[Mike Hillis]

Four clues to help.

First is the large deep iron false. Look at the Depth Gauge in conjunction with the Confidence Bargraph. The two will not agree. You will either have the depth bar reading deep and the confidence bar reading full or mostly full, or you will have the Depth bar showing a shallow target and the Confidence bar showing nothing or only a couple of bars. Hi coin tones and these two bar graphs not agreeing is large deep iron.

Those steel bottle caps and other ferrous trash will often cause the FE bargraph to spike a bar or two. Pay attention to the FE meter and you'll see this take place. If you get a somewhat bouncy coin reading and the FE bargraph raises a bar or two (or even more) you can know you've gotten a round ferrous target.

Lastly on the the deeper targets, match the pinpoint audio to the depth bar. If you have a broad sounding pinpoint audio on a target that reads in the 8" + range, you know it's not a coin. The pinpoint audio works very well in telling you round ferrous from coins.

Last thing that I've found helpful is to switch over to 2+ with a low disc setting (6) for the really questionable targets and see if I get a low tone over the target. This will often show the rusty iron for what it is.

HH

Mike

 

[Mr.Bill]

You mentioned coming from being a Explorer user. Just a reminder, The F75 requires a lot faster sweep speed than what your accustom to using with the Explorer.

Slowing down the sweep speed on the F75 will cause poor, and inaccurate ID'ing. I'm not going so far as to sugest that increasing the sweep speed will end all your problems, bu it will certainly help.

 

[tab-nabit]

Interesting observation on the Depth Gauge in conjunction with the Confidence Bar graph, and FE bar graph to spike a bar or two.
I'm new to the F-75. I have been hitting a new spot that's been giving me some finds better than what I have been doing in a few years at other places. I been using a few other machines with small coils and been thinking of giving the F-75 a whirl in this new place. The area is so terribly loaded with trash and there is more bottle caps and screw caps than I have ever seen. Working this area is a bit frustrating but the finds got me hooked. I can't hardly find a coil swing without several bottle cap/screw cap hits, so this is my reason for small coils.
I never though about the FE bar graph spike approach but if I can get this F-75 to work in this area with it's coil, maybe I'll look for the few interesting observations you posted.
Maybe this is an area where I need to get out of the dE mode and maybe try the bc mode. Fore tone I been using the dP so I might pipe this down a bit but still set for nickel high tone.

 

[Streak!]

dig the freaking things and get it over with. I've used many many machines, and hardly EVER dug rusty steel bottles caps, but with the 75 its almost unavoidable. I've tried everything in the book to try to hear the difference (FE graph, confidance bars.etc...) but they are unreliable in positively Iding caps...sooooo I just dig em'. The closest thing I've seen here to an actual useable answer was from Mr. Bill. A faster swing speed will have a bit of an effect on them, but not enough of one to be really reliable. Most steel caps will make kind of a "zip' sound when you swing over them fairly fast, (as opposed to a bit smoother sound from coins)and the VDI most times will vary widely. still..... Ive had good coins do the same thing . I HAVE gotten to where I can make somewhat of an accurate guess on them (steel caps), but still have to dig them "just in case". I have decided the answer is to just dig em all in the first place, as thats usually faster than trying to analyze the target. Fortunately, most of my sites (colonial woods sites) dont have many caps in the first place, so its not really much of a prob most times. In other areas I dig you will get the odd one, but its worth digging them to be sure its not a good target. A good coin with a nail stuck to it will sound a lot like a steel cap. bottom line.... if steel caps sound good with the 75, its not really an issue. Ya ought to be digging em anyway!!! Streak!

 

[Jason in TN]

If I am in a area with a lot of caps like the beach. When I get a good signal swing the coil and back or pus it up or push it foward until you lose the signal off the front or back of coil. Center of the coil the target will sound good. As you swing the detector as you reach the tip or end of the coil the signal will change to a iron grunt just before it goes away if it is a cap. If it is a coin it will sound good all the way until it goes away no iron grunt. Try it and see if it works for you.

 

[jim tn]

Jason, the method you describe is what I do, too, and it does work quite well. I used Mike Hillis bar graphs method this morning also and dug a couple caps just to see and his method is right on as well, at least with the two I dug. HH jim tn

 

[Chris(SoCenWI)]

I've been out with the F-75 a few times since this post. I have noticed on the big deep iron that I might get a great sounding hit with solid consistant ID but the confidence meter is way low. Luckily I have a periscope and can probe for a target before digging.

A couple of questions... The depth bar has only three segments- bottom half, top quarter, and second from top quarter? I did not see the alternating depth vs. confidence that you mentioned.

Also been watching the FE bargraph and not seeing a strong correlation between ferrous or coin, just when I think I'm seeing a pattern the next one I dig is the opposite of what I expected. Also question on FE bar; the ID number on the display seems to reset itself after a couple of seconds, FE bar doesn't seem to reset to zero at the same time, seems like it will hold it's value until you go over another target with a lesser FE number?

I have been playing with sweep speeds and not seeing much difference between a long fast sweep and short "minelab" wiggle sweeps. I do have to say this unit does pinpoint nicely without even using the pinpoint trigger switch.

One of these days will have to spend much more time in the non-disc settings and see what happens.

Chris

Thanks

 

[Chris(SoCenWI)]

n/t

 

[Rick(ND)]

n/t

 

[Scully]

Do you know there is a club in Madison, Four Lakes Metal Detector Club? We have our monthly meeting tonight, 7:00, at the Truax-Longmeir VFW club north of the Dane Co. Airport. If you would like more info, give me a call on my cell, 608-213-6622.

 

[Chris(SoCenWI)]

I was living in Delavan, now in Beloit. Probably been a couple/three years since I made a meeting up there.

Basically this is the first new detector I've had since buying the explorer a few years ago. Trying to get a sense if what I am seeing is normal or just doing something stupid. My sense from the forums and PMs is that it is not. I know I need to spend much more time learning the language of this machine. Learning the explorer did not happen in a day/week/month/year.

I hope to make it up to a meeting some time this fall.

Chris

 

[jbow]

n/t

 

[jbow]

I don't know if you have access to try one but.. I recently bought a Cortes and frankly didn't like it much until today when I tried it today with a 5.75 coil. I went to a vacant lot and it did well there with the small coil. There is a spot on this lot that is loaded with bottle caps and i noticed that the Cortes does not signal on them like the F75 does. The ones laying on top of the ground gave no signal at all. The Cortes will never replace my F75 but it has a place now.

Julien

 

[vlad]

At both beach & inland-iron alloy's change, non ferrous does not iron grunt.

 

[Scully]

I have about 60-70 hours it now, so if you want to talk and compare notes, we could learn from each other. Give me a call some time, eves and weekends are best, cell is 608-213-6622.

 

[Idaho-Marke]

n/t