Noise Cancel correlation to particular finds,Gold etc.

Ok here goes.
Question for Tom Dankowski and others.

Many of my collegues who use The Ctx and or an Etrac are convinced that there is a direct correlation between certain noise cancel no,s-channels and a set of particular finds/metals etc like very fine Gold, or large copper coins etc.
Some are even saying that Certain noise cancel channels are better for the beach and some channels better for inland.etc etc.

I personaly belive that these assumtions could decieve and misguide new and inexperienced detectorists in to a set in stone method of detecing for partucular metals when in fact it is just by coincidence that the channel,s they are actualy selecting for their area are infact giving them the most stable and emi free detecting session in the day and nothing to do with channel 2 for example being better for fine gold.

I personaly do not agree with the above theory, as i believe that it all comes down to an average Emi level across the country and is simply just down to coincidence that the same channels selected are giving a reduced Emi effect there fore increasing their finds rate with what ever is lying under the coil at the time on any given day.

I may be wrong with my own theory on this and will stand and be corrected if this be the case, so
i would like to Know Tom What you think about this theory, and if detectorists are going about this the wrong way by selecting channels and apportioning them to certain metal typesonly and with no focus on Emi.
Thanks
Keith



Edited 2 time(s). Last edit at 10/25/2013 05:24PM by whigsvolt.

Whiggy, I thought you were a keen viewer of this forum? There's several topics on the subject of Minelab noise-cancel channels and their frequency, and the possibilty of 'tuning' for greater sensitivity to high / low conductors. I didn't follow them too closely, as I don't have a Minelab, but the jury was out on whether it really made much difference.
Here's a couple:
[www.dankowskidetectors.com]
[www.dankowskidetectors.com]
Plus:
[www.metaldetectingforum.co.uk]

There does appear to be differences in target ID values on both air-tests and in-ground detecting between higher and lower Noise Cancel numbers. Experimentation has a way of convincing yourself into trying Noise Cancel hunting techniques.

Here’s a previous post on a possible link to a shift in target ID values and Noise Cancel numbers.

[www.dankowskidetectors.com]

Another, very convincing, test is air-testing small gold jewelry. I air-test all of my gold jewelry finds, hoping to find ways of increasing sensitivity to the hard-to-detect small gold jewelry.

One of the most (self) convincing air-tests was with an open loop hoop gold earring. While constantly sweeping the 14k open hoop earring right in front of the coil at a constant rate, Noise Cancel #11 could consistently pick up the faint signal, #10 could sporadically pick it up, while all the other numbers, 9 down to 1, could not detect it at all.
Although there are an array of problems with the high Noise Cancel numbers, such as increased sensitivity to certain hotrocks, slightly higher target ID values, less stable target ID values, etc, it has worked for me at a beach that I hunted extensively.

My best advice is to experiment with different targets, both air-tests and in-ground tests. Especially with very small, very low conductive targets, those that are very difficult to detect.

Perhaps you can find the right settings that are ideal for your hunting conditions.

Detecting since Feb, 2010
E-trac with 18"x15" SEF, 13" Ultimate coil, Pro coil, Minelab 8" coil, 4.5"x7" SEF, Sunray target probe
CTX3030 with 17"x13" DD coil, 11" DD coil

Keith........ time permitting.... you may want to start by reading the thread titled: "Rcpt Ack of F75 LTD Prototype" ,,,,,,,,, especially the section(s) about EMI mitigation. This should help a fair amount.

NASA-Tom Wrote:
-------------------------------------------------------
> Keith........ time permitting.... you may want to
> start by reading the thread titled: "Rcpt Ack of
> F75 LTD Prototype" ,,,,,,,,, especially the
> section(s) about EMI mitigation. This should help
> a fair amount.
Many Thanks for the prompt reply Tom on this at times contentious subject of The Noise cancel-frequency shifting connection with various metal types etc.

I have just finished reading your Emi and other related finding,s to the F75 etc and it was facinating and extremely helpfull indeed especialy due to the fact that i own the F75 Ltd and have now gained a much better insight in to ways that i can set up this superb detector that will benefit my success in the hunt.

I however still feel worried that certain influencing elements are convincing new and or inexperienced detectorists to set their detectors on ceratin noise cancel no,s so that they can have the advantage of finding fine Gold and or larger relics like older copper coins, instead of focusing on eliminating the Emi in their area of detection.

I have allways ground cancelled and tried to eliminate Emi First as opposed to just jumping straight in and setting the noise cancel channel to 2 say on an E trac for fine gold or jewelery and have found that this normaly works fine.
As far as the Ctx 3030 is concerned which i also use, i have found that the Auto method works fine, but we all aim to strive and do better with some selecting particular noise cancel channels for a particular set of finds.
I am no electronic expert, but i do try to understand what has been said, and feel allot more confident with what i have read so far in these Discussions.

I was particualry amazed at the finding,s presented by you Tom with regards to the Ltd F75,s little 5 inch double d coil and the depth and better tollerance to Emi it has over the Stock coil, so i cannot wait to try this one out when i get home on Thursday and will let you all know how i get on in a field that i have done for years with some 16th century silver coming of the same field.
Thanks again for some facinating and helpfull reading.
Keith



Edited 1 time(s). Last edit at 10/26/2013 10:18AM by whigsvolt.

Pimento Wrote:
-------------------------------------------------------
> Whiggy, I thought you were a keen viewer of this
> forum? There's several topics on the subject of
> Minelab noise-cancel channels and their frequency,
> and the possibilty of 'tuning' for greater
> sensitivity to high / low conductors. I didn't
> follow them too closely, as I don't have a
> Minelab, but the jury was out on whether it really
> made much difference.
> Here's a couple:
> [www.dankowskidetectors.com]
> .php?2,23979,23979
> [www.dankowskidetectors.com]
> .php?2,24272
> Plus:
> [www.metaldetectingforum.co.uk]
> ?f=99&t=48503
Hi Pimento.
Yes i have looked in before, a few years back, but it was just a glance, so i have basicaly missed out on some good info up until now ofcourse.
I like the type of discussions that take place here and itis nice to get in to the bare bones of how our detectors function and the issues that many people including my self need to understand more.

I will be coming on here allot more Pimento and will attempt to improve my understanding of some tecnical issues despite my 25 years in the hobby as i feel we never stop learning in this great hobby of detecting.
Thanks
Keith

Keith,

Small/fine gold jewelry is much more affected by Grnd Bal settings......... then............ by EMI. This prompts me to recommend you to read the Garrett AT-Pro Field Test thread. In a nutshell........ many small gold items can disappear with certain Grnd Balance settings.

Thanks for that Reply and the info Tom.
Keith

When an auto noise cancel on the E-trac or CTX gives me a high number, 9-ish
I'm pretty happy knowing it will see finer gold and low conductors.
Maybe I'll just flip into manual and give 11 a go, I reckon this to be the highest frequency band available.

However there is no use what so ever in trying to convice the auto noise cancel running on a number 2 or 3 to go into the high numbers.
So then I just settle for coins and large gold finds.

There is some correlation, but I find the auto noise cancel number to be a very helpfull guide. Not something you can force feed the detector.

HH
Johnb

Concerning the noise cancel on the Minelab machines and my Etrac. Tom is exactly correct, it is more geared to choosing a channel least affected by EMI. I've have proved that many times and can say the Etrac is better at adjusting for EMI than the F75. In fact, that is why the Etrac can detect deeper than the F75 in both medium to high EMI areas. Sad but true. On my F75 I've noted, when EMI is extremely high I loose about 1/2 of the air test distance. I carry a couple coins with me to test performance when EMI is really bad.

Certainly, the F75 stock 11" is deeper than the 5" when conditions allow.

The problem I've found in urban areas is that, more often than not because of EMI, conditions do not allow.

That 5" is an amazingly deep little coil and superb at unmasking as well. And I can run it hot in urban settings, 80 or higher in most locations.

I wish people could see the Boost Process ran on 99 sens in iron with either coil..


Its a shame only certian machines can do it.....Its AMAZING the difference it make's on unmasking at depth...

The Boost Process 99 sens will unmask in iron at depth better than anything I have used...the Euros GMP/DTVG have it in the top few inches but the BP mode gets it's advantage at depth in iron like no other..

Keith

I wish I could see that too, Keith!

As years go by....... and skill-set improves....... the attributes of 'boost process' are (finally) starting to be discovered. Yes,,,,, EMI is a (mitigat'ible) issue; yet, can be overcome. I still find myself cursing at the EMI-prone platform, , , yet, cannot live without it....... due to 'boost process'.