Thought provoking

[markg]

Here lately I've been digging some very iffy beeps.
Point to mention:
I was hunting in an old school yard recently, not finding very much.
I had been passing up many targets that broke up or seemed to be just chatter.
Time was quickly passing away so I decided to start digging some of those not smooth, not repeatable beeps that I had been passing up.
Oh by the way, before you ask, my GB was only slightly positive and the discrimination was set to the lower end of foil on my Tejon with the stock coil.
My first signal was not loud in any way. Didn't repeat well (broke up), but did have some tone to the beep. So I decided to dig. To my suprise it was a quarter at 2" deep. Well needless to say I immediately checked my GB, but nothing had changed. Checked the area in all metal but didn't find anything else. Brushed it off as strange and continued to hunt. Then another signal, not as loud as the first, didn't repeat at all. So I dug and there about 2" down was a silver ear ring. Now I can say I was really starting to wonder about the other signals I had detected earlier. As I looked at the empty hole where the ear ring was buried, the word masking came to mind. Was it possible that something was masking or robbing some of the signal my detector was emitting to the point that a quarter at 2" deep couldn't give a clear loud beep as usual.
By chance, a couple of days later I ran across this article which explains it very well.
Hope this helps.





http://www.dankowskidetectors.com/behindthemask.htm

 

[slingshot]

That's probably THE most thought-provoking article that I've read and my thoughts on how to search for coins is changed for as long as technology allows! A HUGE thanks!

 

[JB(MS)]

Interesting article, but not necessarily very accurate when detectors other than what he used are chosen. I read his test in Western and Easter several years ago and didn't think much of it since the three detectors he used, a Fisher CZ, Whites 6000 and Minelab Excalibur, are more susceptable to masking than many, maybe most, other detectors. I've had five CZ's, two 6000's and two Sovereigns, which as you know is the same as the Excalibur except for not being waterproof, and they were not good in even moderate trash. It's easy to believe they would fail to see a dime under a small staple. Some of us duplicated the test he did using various detectors and the two CZ's I had at the time gave result similar to what he said he got, but with discrimination set to reject a rusty 16 penny size nail my Gold Mountain GMT 1650 and Jim's Compadre ignored the staple except for a very slight loss of depth on the dime with the staple over it at any depth. Dankowski's intent may have been good but his choice of detectors for a masking test virtually assured the results he got. If I remember correctly there are some posts about Dankowski's article in the archives of Carl's Detecting Equipment Forum that were made right after it was published, probably Carl's original forum, and results that some of us posted when trying the masking test with a staple. The soil conditions here are very mild, virtually mineral free, most detectors go deeper in it than most other places, and having used some of the same detectors here that Dankowski has written about, and having talked to others who used them plus reading the results others have had using the same detectors on Carl's forum, I can't help but think that Dankowski just might be prone to stretching things a tad.

 

[slingshot]

Yeah. And you guys are gonna keep on until I get my Compadre.

 

[Pap]

I would have to agree with you JB(MS). I really can't say anything about the new Fisher units other than what others have told me which is they are better than the older units regarding the masking effect but not to the point that we sometimes read on the forums. After reading the article mentioned when it was released I did some testing and found some of his conclusions to be somewhat accurate. Masking will effect all detectors. However the effect it has is not the same on all detectors.
Pap

 

[rmptr]

The Fisher CZ's as the Tejon are indeed very powerful machines.

Perhaps the situation here is they are going into overload when they experience the masking.

Hence, the Tabdog does very well with the Compadre.

It is never marketed as a very powerful machine... and is rarely in that condition of overload.

Simple, yet effective.

HH
rmptr

 

[tabdog]

I tried to get this discussion started several months ago.
The article, although some what misleading, brings up
how masking can effect any VLF detector. Even the
Compadre.

I learned about a staple or something smaller causing
silence, to some degree, and a response in one direction
but not the other. Also a start of a signal, being cut off,
sounding like a pop. And then not repeating, unless you
swing it just right.

Why do you think I dig so much all the time?

Why do you think I use the Compadre all the time?

How do you think I found all that gold?

I know how to discriminate, but that don't help me.

Monte knows all about this.

I learned a lot from Monte, and then things you guys taught
me confirmed what Monte says.

More powerful metal detectors can see more and have more
masking.

That's why we use small coils on them.

I us them when the hunting calls for it, but the Compadre is
bringing home the bacon.

I get most of my gold within 3" or 4". Usually less.

The Euro and the Vaquero can get the job done. But you have
to fool around with them more.

Sometimes it works good to go over it with the Compadre, and
then go over it with the more powerful one.

But you have to dig a lot to do that. But if the stuff is there,
that's the best way I know to get it.

HH,

 

[tabdog]

Thanks for the input JB and Pap.

There is more to this subject than

can be easily understood.

It takes trial and error.

Just experimenting with it has taught me a lot.

I think it has helped me find more good targets.

HH,

 

[bjsone]

This is the best article I have seen on masking in all of my 39 years of using metal detectors. I use test gardens and several other techniques to test this premise and know it to be true, but Tom said it best. Thanks for sharing.

 

[Pap]

Yes indeed. That is why detectors with a VDI read out can be very deceiving. The masking effect will cause some targets to simply not respond while others will respond but the VDI will be inaccurate. The problem with Silent Search in discrimination is the lack of knowledge when passing over a target within the discrimination window. In all metal this doesn't happen. At least for the most part. That momentary pause of the AC mode over a discriminated target can mean that there is no response to another target in close proximity.
Pap

 

[JB(MS)]

There is more to the subject than one might think. A lot of variables come into play when using or testing detectors, especially when target separation and masking are concerned. Soil conditions is a biggie but ground balance setting, sensitivity setting, sweep speed, how close the coil is to the targets being tested, the position of the targets in relation to each other and discrimination level also have a decided effect. I've spent numerous hours doing masking and target separation (two related but completely different characteristics by the way) tests with a lot of different detectors. Of the VLF's the GMT 1650 and Compadre gave the best results, but a Whites Classic III wasn't too far behind. Here's the rub though. The results I get with a detector with the optimum settings for the tests I do, or the places I hunt, are specific to my soil conditions and settings, and someone in different type ground using different settings could, and likely would, get different results. It took me a long time to learn that a detector that worked great in upstate New York, or that durn red stuff they call dirt in parts of north Alabama, wouldn't necessarily work as well here. Sadly, many on the forums never learn and continue to tout this or that brand or model as the absolute best for every location, period. However, with absolutely no intentions of starting a row, the soil conditions in the Titusville, Florida area where Dankowski did his tests are very similar to the conditions here, close enough the results should be similar and they were with the detectors he tested. But as I said above, the three detectors he "tested" virtually insured the results he got.

 

[tabdog]

Something that is kind of hard to understand is that with my Euro
or my Vaquero, I spend most of my searching time in all metal.

But with the Compadre I can get by quite well without it.

It's two different things.

They all three have good qualities.

I am just fortunate to have good tools to work with.

Sorry I don't know about other brands very well.

But for right now, things I am satisfied with the ones I have.

And if that ain't good enough, then I'll just take off with my Silver.

HH,

 

[markg]

Being very experienced with the Tejon, how would you go about dealing with the masking effect in relations to the Tejon?

 

[markg]

Several years ago I planted a test garden in an area close to where I live. I made a detailed map of each target and it's depth. Played around in the garden for a few weeks, had a great time listening to my machine. The targets ranged for 2 to 6" deep. Well as summer approached I lost interest in the garden and started hunting local schools.
The next year renewed my interest in the garden. So I took my map and went testing. I found to my surprise that all but two of the coins I had burried could be found. Of course I thought someone had dug them up. I tried different settings, lower disc settings, GB both negative and positive, nothing seemed to help. So using the map I began to dig up some of the coins that were silent. Yep there it is, but why could my not machine find it. Carefully I began to widen the hole. An old rusty nail here and there. Then I remembered that years ago there was an old building in the same location. The rusted nails were masking my buried coins. Finally I set my machine to just pop on a rusted nail and some of the seemingly invisible coins revealed there location.
Needless to say, I moved the garden to a cleaner area.

 

[Gunnar of bradford MN]

n/t

 

[Gunnar of bradford MN]

n/t