Old Compass detector CAN see through nails...

[Chris(SoCenWI)]

Hey All,

I know this is a little off topic for the XS forum, but have posted here for years and the "seeing coin through the nails" topic has been discussed many times over the years. I'm also posting this on the Vintage Detector forum.

My first detector was a Compass Coin Hustler II. Later in High school I bought a Compass Coin Magnum for big bucks(for me).

Long story short....

It's been sitting in storage for years, today I was tidying up and debating whether I should just toss it. I had heard of early Compass model's ability to "see" through iron but was a little skeptical. Today I put some new batteries in, hooked up the coil and starting swinging targets in front of the coil.

I was amazed. A wheat cent held together with a huge nail gave a good signal no matter what the orientation of the nail.

I've done this with my explorer XS, CTX3030, Fisher F-75: they can only see a co-mingled coin/nail signal in very specific circumstances. Makes one go "hmmmm????!!!!"

Depth isn't that great and not sure how it will work in actually "in the ground" conditions, but I know there are many iron infested sites that we still miss most coins with modern detectors.

It needs some TLC but I'm definitely not going to trash it; might be a good winter repair project. Might need new capacitors and perhaps could be mounted on a more ergonamic rod set up.

I just saw a couple of youtube videos of others showing the same results.

So...

Anybody have some actual in the field experience with these units going over ground pounded with modern detectors?

Anybody done any repair work on these? Does Keith Wills or others still repair?

Chris(SoCenWI)

 

[IDXMonster]

I chucked my 66-tr not long ago,I'd like to know what you want to know. Depth...does it do the same in the real world. I've got a particular farm that I found an LC at with piles of nails,it's unreal. Does yours run high kHz Chris? I think the 66-tr was 100 kHz,I could be wrong....

 

[Chris(SoCenWI)]

-- moved topic --

 

[REVIER]

I have a Judge 2 that needs some TLC but it kinda works and I keep it around just for special site.
Does that see through iron thing like a top notch magician in Vegas...also 100kHz.

Keith Willis does repairs but he just had some major back surgery so that service could be on hold for now.
He is out of East Texas.

 

[Chris(SoCenWI)]

Kevin,

Don't know what frequency it runs. I would certainly think any modern detector maker would want to offer a detector with these kind of capabilities. I suspect there has to be a down side to this or everyone would be doing it.

I might try put it on a oscilloscope and check it out.

Chris

 

[Nauti]

Things never work the same in the real world like they do in air tests im afraid.Stick the nail to the coin with a piece of blu tac so there is a slight gap between the coin and nail and repeat the test.Did you use just enough discrim to knock out the nail,if this is the case,by adding the coin to the nail (touching), all you have done is increased the mass of the target enough to get a signal......your detector is'nt actually seeing through the nail.
The best thing to do is actually repeat the test on buried objects with the nail and coin at different depths to each other etc.This will show you how good your detector is in comparison to other machines......not air tests.I used to use a sovereign on trashy sites which were thought by most to be useless in such an environment and they were if you did such tests in air or with targets placed on top of the ground.However,it used to pick out good targets regularly that were close to iron in real hunting conditions proving that the machine performed better on buried targets.

 

[coinhunterseth]

There is no disc on the ealry tr compass detectors. It sees the coin under the nail because its 100khz frequency cannot saturate the iron enough to see it. They can't detect iron, but will see non ferrous objects beneath it. however, they get terrible depth.

 

[Nauti]

They will only see a good target if there is enough of the target sticking out from under the iron........they cannot see a good target that is completely covered by iron.As I said before,in a real world situation when targets are deeper than the iron above them,they will struggle.

 

[Tom_in_CA]

Yes, the Whites 66TR was akin to the Compass 77b, coin-hustler, etc..... (all the older compass's with 100 khz all-metal TR's). However, even though the 66tr was also an all-metal TR, it was never as good as the Compass of the same era. The Compass's just did it smoother, deeper, or whatever.

I had the 66TR as my first machine in about 1976. Although only 3 or 4 yr. old used machine at the time, it was already a dinosaur even then. But for a short period I hunted with a guy using a 77b in the same type school yards. And his was noticeably superior.

But in-so-far as ability to null on (and see through) small iron, yes they were similar.

 

[Tom_in_CA]

On the contrary: There doesn't need to be a "peak of the coin" sticking out, in order to get a signal. They will get the coin, even if the coin is covered entirely by the nail.

But, I suppose, on what you mean by peak. Because if you mean a nail big enough that it totally obscures ANY view of the coin, then by definition, you're talking about a "nail" that's got to be pretty frickin' wide (like RR spike?).

 

[slingshot]

On the contrary: There doesn't need to be a "peak of the coin" sticking out, in order to get a signal. They will get the coin, even if the coin is covered entirely by the nail.

But, I suppose, on what you mean by peak. Because if you mean a nail big enough that it totally obscures ANY view of the coin, then by definition, you're talking about a "nail" that's got to be pretty frickin' wide (like RR spike?).

Yep. And what most didn't realize was the bfo's reacted similarly.

 

[Chris(SoCenWI)]

And then it only sees the coin if the nail is almost perfectly aligned with the center web of the detector. What I find interesting is that the older detectors can see the coin, and now the CTX in target trace mode can also indicate a non ferrous target masked by a ferrous target no matter what the orientation, but only on the screen, no corresponding audio. Seems to me there could be another huge break through akin to when the XS first came out, old worked out areas coming alive, if some company could make a detector that has the ability to tune out ferrous objects.

Chris

 

[Tom_in_CA]

Exactly. And you would THINK that with today's massive improvements of computer technology, that it would be a SINCH to replicate this old "iron-see-through" trick, right ? About the closest we have today, is various 2 filter machines, like the Tesoro Silver sabre. They can see up to about 2 nails over a coin (if you tried hard). But not as good as the up-to 3 nails that the 77b was capable of. But alas, the market today is driven by "depth depth depth". So it might be a hard-sell to the consumer market, to tell them their depth will be limited to 4", doh!

About 20 yrs. ago , a Fisher representative came to give a lecture to the San Jose CA club. The talk was just typical manufacturer info on their latest models and such. When the meeting was over, I approached the guy and asked him "How come no one is making something today that will replicate what the old all-metal TR compass' could do?" At first, he had no idea what I was talking about. So I did my best to explain the issue. He took my name and ph. #, and said he would talk to one of the Fisher engineers about this, and they would "get back to me". But alas, no one ever called me. So I just forgot about it.

Then about 5 yrs after that, I found myself travelling through the Los Banos part of CA (back when Fisher used to be headquartered there). And stopped in to see their factory, museum, etc... Then I approached the the desk clerk and posed the question, explaining how , years earlier, I had asked their rep. and no one had ever called me back. She went into the factory and brought out the person who had spoken to the San Jose club years earlier. I reminded him of the question, and joked that he'd never called me back. He said it was because not even the engineers knew what I was talking about (or they probably just didn't care, is what I think).

But anyhow, I asked the guy to come out to the parking lot, and I would SHOW him what I was talking about. I pulled my 77b out my truck, and placed a coin on the blacktop parking lot. I demonstrated how the machine would, of course, pick up the coin. Then I took 3 rusty square nails, and placed them at a different spot on the parking lot. And the 77b nulled (no signal) over them. Ok, so far so good. But naturally, so too can ANY discriminator on today's market "null/reject nails", right ? So at this point, he was still thinking "so what ?"

Then I put the 3 rusty nails ON TOP of the coin, and STILL get a positive signal. The guy was very intrigued, and announced that Fisher had a machine that could do the same trick. He went back inside, and brought out a particular currently made Fisher. I forget which model. And ..... when it was all said and done, he could NOT get it to replicate the trick. I mean, to the extent that he could get a signal with the nails over the coin, yet he had to admit that it was about the same as going over the nails sitting solo.

So AGAIN this rep. said "I'll talk to some engineers here about this, and get back to you"

That was ~15 yrs. ago, and I never got a call back . Sheesk.

 

[Chris(SoCenWI)]

That is an interesting story.

I've done enough detecting to believe raw depth is not the most important feature; target masking is a much larger issue and I think the Explorer XS did so well when it first came out because of it's DD coil design. I believe it was one of the first widely sold detectors to use a DD, and the different magnetic field pattern it generated vs the older concentric coils unmasked a whole lot of finds. Many time I've detected a site that I know has been hit hard over the years. If I'm the first guy with an explorer I'll make lots of nice finds, but few if any are perfect hits. They are next to something that kept older detectors from finding it.

And I believe there is still a whole lot more to be found because of masking, and that is why I'm excited to get my old compass working. Why a metal detecting company is not pursuing this makes me wonder. I just assumed that there was probably some technical reasons, but from what you are saying the young whippersnappers at the company are unaware of previous technology. I would still buy one even if depth was limited. Sidewalk/street tear outs and near houses coins are often shallow but surrounded by iron.

It's kind of sounds like Etrac and CTX situation. I so much better like the screen set up on the earlier FBS models where the targets were spread all over the screen. Now Minelab has stuffed everything into the 12 ferrous line. Basically to get rid of the "DREADED S CURVE" (something I never heard anyone EVER complain about until someone tried to explain that this was the reason they did what they did on the Etrac) they threw away most of the information the detector was capable of showing. Sounds like some marketing schmuck got involved in the design process.

Apparently my Coin magnum runs at 5.73khz vs the 100 khz for the 77b and 94b. That is a big difference. Do you think this may be an issue? That the coin magnum will be worse for see through than the 77 or 94? The little playing around I did seemed to show it ignoring iron, and this was with the ground balance set where ever I had it years ago.

Any ideas why these detectors where able to do this? I was thinking that basically it was ground balancing on steroids; that it was just not seeing the iron in the dirt but the iron in the iron. Perhaps not.

Next time I get to Minnesota I'll have to play around with my old Coin Hustler and see how that behaves.

Chris

 

[jarrow]

Guys go to the compass forum they will tell you everything you want to know about compass.

 

[Tom_in_CA]

Chris, the very first foray that Compass made into the TR discriminator market (at the advent of the evolution of discrimination) was a TR/TR machine (as opposed to a VLF/TR machine). And yes, that all-metal TR circuit on that, was identical to the 77b's all-metal TR. So yes, it would do the "trick" (in the all-metal mode of that machine). I forget which incarnation of Compass that was. Then the next one that came out was VLF/TR. That will NOT do the trick.

Hopefully someone will chime in and set straight which was which.

But I have always just kept it simple and used the 77b. There's plenty that were sold in those years, so it's never hard to find one at flea markets, ebay, etc......

 

[Chris(SoCenWI)]

That is why I was wondering if the 100 khz is the key to ignoring iron. I did see the needle consistently indicate "Treasure" with a penny and nail together.

I'll have to play some more.

Will post when I do.

 

[Chris(SoCenWI)]

n/t

 

[REVIER]

n/t

Use Google...it is easily found

 

[Tom_in_CA]

yes, that all-metal TR was the trick.. 100 khz. But in all other ways, a dinosaur and pain-in-the-b*tt.

A humorous story to this thread: In 1980, our city tore out all the downtown shopping district sidewalks for an urban renovation streetscape project. Since it was an urban demolition project, there was lots of nails, rust, iron, etc... Naturally, md'rs were all-over it for sidewalk demolition hunting. And go figure, this was the era when the following machines were "all the rage" : Whites 6000 d , Bounty Hunter red-baron, and a few vlt/tr's were still in use, like the Garrett groundog. But then along comes a guy swinging a Compass 77b with "no discrimination". We looked at him with pity & disdain, as, ... obviously, we had the "latest greatest discriminators" . And we had the depth, etc...

But lo & behold, the guy with the "dinosaur" kicked everyone's b*tt ! He spanked us 3 or 4x to 1 on coins. Seated, barbers, IH's, etc... I distinctly remember talking to this guy (I was only a teenager then) trying to figure it out. He tried to explain: "This machine doesn't see the nails". But that made absolutely no sense to me. I mean, duh, wasn't our discriminators LIKEWISE passing the nails ?

It took me another 10+ yrs. to figure it out. I finally understood the concept of disc'ing OUT versus seeing THROUGH.