Read this before you compare detectors

[EZrider]

Information on compairing detectors
On many fourm sites compairing detectors seems to be a hot topic. What is deper,faster lighter ect. I am writing this to give everyone some food for thought. As well as to inform new people. I will also cut and paste some clips from different areas of information.

Two names that should be well known are Dave Johnson and John Gardner. These two people are the direct result of what we detectorest swing today. Here is a clip from a interview on what thay had a hand in developeing.

Dave: "Old Fisher: 1260, 1220, 1210, 1225, 1235, 1265, 1266, 1280, Impulse, CZ6, CZ5, CZ20, Gold Bug, Gold Bug II, TW6/Gemini, FX-3, and several industrial products.
Tesoro: Diablo MicroMax, Lobo Supertraq.
White’s: DFX, Beachhunter ID, GMT, MXT
Troy: Shadow X5
Bounty Hunter & related products: nearly everything we manufacture. Many of these products are adapted from the original Teknetics which was designed by George Payne. The Teknetics T2 however was an entirely new design.
New Fisher: F75, F4, and everything else since then.
On most of the above I was the lead engineer. On the White’s DFX and Beachhunter ID I developed the multiple frequency circuitry, and other engineers designed products around that circuitry. In addition to the above there are many products on the market which are adaptations by other engineers of products I designed."

John: "Bounty Hunter : I have had a hand in most of our current line up from the bottom to the top, from Guardian to the Time Ranger.
Teknetics : T2 I was main programmer
The Fisher’s : The F4 and F75"

Now let that sit for just a minute. That’s a big list from diffrent companys by only two people.
Now my next rant is everyone wanting the deepest out there but yet people fail to realize that we are limited by how much power output on the trasmit side our detectors can have. This clip is from Thom Dankowski, Fisher Intel report.

Contrary to popular belief, the sensitivity control
on most modern metal detectors has nothing
to do with transmit power. When a metal
detector is turned on, the power (measured in
milliwatts) is a fixed/constant output, The FCC
regulates maximum output/transmit power to
100 milliwatts. Sensitivity controls only the ‘receive’
circuits of the detector.

So with this the only real diffrence from detector to detector is how the circuitry handles what we hear. So when comparing detectors you are comparing functions and not the power.

 

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[rwsnc]

Thanks for the post. I've always been suspicious that I didn't fully understand "Sensitivity". I tend to run mine down around 15 to get my x70 to "settle down". It sounds like I haven't been giving up much depth in exchange for stability.

 

[TomNWMI]

Here's a couple links on depth and transmit power for some good reading.

http://jb-ms.com/Carlsforum/Oct31-2007/1190584476.html

http://jb-ms.com/Carlsforum/April2002/5080.html

 

[EasyMoney]

Wow Badger!

Excellent! You and I both have been saying nearly the same thing ever since way back when..

There is seldom 2" difference in depth between a cheap detector and an expensive one, regardless of what some may claim. Some detectors operate more slowly, and some operate very quickly. Some operate a bit more efficiently and some have more superior discrimination and process information more precisely and a bit more accurately, but the truth is, that there are mostly subtle differences in how well they operate save for some having the propensity to discern somewhat better between good conductors and bad ones.

This is the very reason why the Tesoro Compadre, Silver Sabre, and Silver uMax do so well in such a wide variety of soils and tend to find more than some other very costly machines. This is exactly why my recent $60 Chinese detector finds more goodies than my $800 Minelab and my $1000 Fisher. It's all in the circuitry, and still, there is little difference in depth between all of them.

I commend you for posting this. And I wish they would post it on the front page somewhere.

Have a good one.

EasyMoney

 

[Dave45]

This link (posted on this thread) says there's no longer a restriction
http://jb-ms.com/Carlsforum/April2002/5080.html

 

[Shortstack]

There is one other bit of info that is ignored too often by experienced hobbists as well as newbies. That info concerns what I call the "field of view" of a detector. That "field of view" is the area inside the cone shaped field formed by the coil. If you want to find more deep, old stuff (wheather coins, jewelry, or relics) you MUST slow down your swing AND decrease the overlap of the sweep areas. We've all read the MDing tips that include overlapping only half the diameter of the coil. Well, you've got to use a lot less than that. If you suspect that the area you're detecting has deep goodies, then you must keep your coil advancement down to about 1 inch per swing. Yep, 1 inch. What you want to do is visualize the tip of the cone of detection as a 1 inch wide paint brush and you are painting the 8 inch level of ground beneath the coil and don't want to have any gaps in its coverage. Just like you don't want to leave gaps in paint strokes when you're painting the walls of your house. After detecting an area along one axis, then recover it along an axis 90 degrees to the first. THAT is how to hunt out an area. Too, many people don't have the patience to do that and complain about not finding many goodies. Why be in such a danged rush?? You will NEVER get to all of the good places anyway, so why not saturate the area you are searching with your coils field of detection and get most if not ALL of the good things in the spot you are searching TODAY?

In another posting a few months ago, I said that it doesn't bother me if another detectorist gets to an area before me because there will still be stuff they missed. Well, the rest of the story is, IF they do the correct thing, they will take away all of the TRASH items they find and THAT is a benefit for ME when I come through. They've removed trash that won't distract me AND they have missed MOST of the good stuff because they were in too much of a hurry and did not "paint" that underground level with their coil "brushes" as I will do. Yep folks, go ahead and do your thing and I'll come behind you and get the good stuff.

 

[EasyMoney]

I would caution everybody about that link mentioned. It is only a statement from another detectorist, unless I am somehow sadly confused about it. Additionally, 9 Khz does not equate to100mHz or 400uHz, or 100 microwatts or 400 milliwatts, etc. etc. There is no relationship between rate of oscillation and useable power. The reason that the power is regulated by the government is because of the degree and depth of radiation, radiation which could and at times does interfere with a device regulating a person's heart, certain medical equipment, general RF, police RF, etc, etc. There is a close relationship though between the rate of power (amperage) used and transmitted and the amount of radiation transmitted in and around the sending device.

On top of that, the "cone" is an imaginary thing, a word used describe the most intense area of radiation, but does not include the entire field of radiation. In fact, there is about a 10-20 foot radius of radiation from the plane of the coil on an average detector, half or so on the bottom and about half on the top. This is why you can detect a coin over the top of the coil too. The field looks a lot like the field present when you place a sheet of paper over the top of a magnet and scatter iron filings on the paper. But the field is not perfect though, and has little flukes and irregularities too. As I said, it radiates quite a distance from the coil plane.

If the circuitry was not designed to amplify only the strongest of radiation nearer the coil, we would be hearing a garbage can lid and a coin at 8 inches, all at the same time. The reason that we don't is becaus the detector's circuitry is designed to NOT signal unless a certain degree of voltage has been achieved after it senses the difference and sends a signal to and away at the end of the transmit device (a DC transformer). When you think about it, this can only rationally be true anyway. Otherwise we would hear not just the coin, but the bar next to it, and the metal wall behind it, plus the garbage can sitting 5=6 feet from it too, but we don't, and we can't, unless we alter the electronics to incorporate everything within a radius of around 10 feet to even as wide and far as 20 feet away from the searchcoil, and to include the coin, nugget too. If a multi-freq unit like one of the Minelabs used more than one frequency at the same time, the same mess would occur.

I hope this helps.

 

[findit]

about the minelab multi(or any other brand that uses multi like some whites or fishers). from what i understand it chooses the best frequency and only uses that one? but does it not have to send out multi first to choose the one.

 

[EasyMoney]

Hey Findit. How ya doin'?

In a way it does, but not actually. It "samples" the soil matrix in a microsecond with a range of frequencies all spaced within a nanosecond, then choses which frequency (might) work best in that soil or those conditions. It works sort of like a rangefinder on a rifle scope. First the distance is measured by looking at the different parameters, then the gun is shot. Sort of like that.

That was a very good question, as yours often are.

EasyMoney

 

[Shortstack]

On top of that, the "cone" is an imaginary thing, a word used describe the most intense area of radiation, but does not include the entire field of radiation. In fact, there is about a 10-20 foot radius of radiation from the plane of the coil on an average detector, half or so on the bottom and about half on the top. This is why you can detect a coin over the top of the coil too. The field looks a lot like the field present when you place a sheet of paper over the top of a magnet and scatter iron filings on the paper. But the field is not perfect though, and has little flukes and irregularities too. As I said, it radiates quite a distance from the coil plane.

If the circuitry was not designed to amplify only the strongest of radiation nearer the coil, we would be hearing a garbage can lid and a coin at 8 inches, all at the same time. The reason that we don't is because the detector's circuitry is designed to NOT signal unless a certain degree of voltage has been achieved after it senses the difference and sends a signal to and away at the end of the transmit device (a DC transformer). When you think about it, this can only rationally be true anyway. Otherwise we would hear not just the coin, but the bar next to it, and the metal wall behind it, plus the garbage can sitting 5=6 feet from it too, but we don't, and we can't, unless we alter the electronics to incorporate everything within a radius of around 10 feet to even as wide and far as 20 feet away from the searchcoil, and to include the coin, nugget too. If a multi-freq unit like one of the Minelabs used more than one frequency at the same time, the same mess would occur.

I hope this helps.

That cone shape has been the traditional way to explain the detector's sensing area and for all intents and purposes, it is correct because MOST people are more interested in finding coins, jewelry, etc. that is buried within the 8 or 10 inches of soil and do not care about engineering gobbledygook that has no bearing on what's being found. It doesn't matter that there are flukes and waves radiating out to 20 feet or a mile. I'll bet you a dollar that at least 999 detectorists out of 1000 are more interested in the area of the field that their machine actually "reads". Ergo, the reason that I described how to use that area to its best advantage in finding goodies to fill their pouches.
That cone is usable in finding a target, that's hiding in the sidewall of a dug hole by tilting the coil slightly on it's side to use the "meat" of the cone to pinpoint better.

 

[EZrider]

I'm glad my post sparked some good conversation by some of the more renowned people on this board. Im glad EZmoney and MB picked up on what i tryed to get accross. I run a F75 and my hunting buddy runs a F2. $1000 vs $200 and he finds just as much as i do. For fun i mark deep solid signals just for him to check and he gets them. EZ said it right about the 6in mark, other than that your buying bells.

 

[EasyMoney]

The reason that metal detector manufacturers don't ever show the entire radiation field, be it electromagnetic, radio frequency, or inductance, is because "they" think the average detectorist is too stupid to understand it, which in truth, sometimes is quite true. Most people who buy a metal detector for the first time don't even know that most are motion dependent. Even my dentist with his 8 years of college didn't know that. His family (his wife is a Doctor) tried a detector I lent them for 2 days and said "it didn't work". The detectors manufacturers really do recognize this ignorance too, that we are mostly a bunch of blue-collar or professional, ingnorant or stupid, low-house morons who only know that "the durn thingy wurks, or it don't wurk", and that many of us don't have a job, and that we metal detect to find "beer money" and that we are a bunch of lazy good-for-nothings. I've even had Catholic Nuns tell me this, plus that I am "taking kids money" when I find a few coins in a public school.

Did I need to explain the way that detector field configurations are, or how they operate? Nope, I didn't, but there are some people like to know how their automobiles work, while others just like to drive the things and don't give a rip about that at all, especially if it's a bit over their head intellectually or scientifically.

If we all understood the process a bit better we wouldn't be making some of the outlandishly ridiculous and really dumb statements that some people make regarding their detector's capabilities. If anybody had the fortune to ever be involved in the making and/or engineering of metal detectors like I have, then they would know before even posting here - how very important my subliminal message was about how and why we cannot depend on that "traditional" "cone" HillBilly ideology. And quite bluntly, the pattern of detection can and oftentimes is, even on some very expensive detectors - so imperfect that it can look like a couple of balloons tied together or two potatoes with cancer, all lumpy and bumpy with pits in it, instead of a couple of so-called "cones" or "V's" back-to-back, one on the top and one on the bottom. Yes, it's very important to know this so that we don't make a fool of ourselves in our ignorance about how the things work, and how we can best profit from this knowledge instead of just living in bliss with our ignorance and luck..

Besides that, we then would really know what we are talking about too, instead of reiterating something that someone else with a 6th grade education "told us", and we believing it all with no questions asked. 99% of the people who ask my advice on here in PM's etc, and other sites too, want the technical answers, not the simple, practical, "science for dummies" ones. So perhaps this is my job here, a technical, yet very unimportant one?

Besides that, my orginal message was primarily written to exemplify HOW things are detected in a small or confined area, not about just "cones". Speaking of cones, scones rhymes with cones and that sounds like a good idea right now, complete with a good cup of Arabica coffee and a scoop of ice cream.

Have a good one.

EasyMoney

 

[Shortstack]

EasyMoney:

I can understand your need to go into a lot more depth of explanation on the technical side of detector operation (because of questions given to you). The reason I use the simplified explanation about the coil cone is because most hobbyists will be like your Dentist and his wife. They would no more understand the really technical part of a detector's operation than you or I would understand the in depth medical terminologies that THEY could dazzle us with. If I mention to someone that several years ago I was an instrumentation technician involved in test launching Minuteman missiles out of Vandenberg AFB, they may think that is kinda interesting. But, if I start talking about system alignments in the silos and synchronizing that equipment with the repeater stations so that the multiplexers / demultiplexers would be in time. etc., etc., it wouldn't be but a minute or two before MOST people's eyes would glaze over. That would be a whole lot more info than they want or need.

Your description of a lumpy and bumpy potato shaped field is useful to many of us because we readily can picture that. How would you instruct a newbie to use his / her detector to allow for the misshapen cone (excuse me, field)? I believe the old tried and true technique of crisscrossing an area is the simple way of make up for the uneven coil field. Crisscrossing and circling around a target will help to make sure the entire area gets detected. That on top of using very little overlap on each swing, as I originally described.

The misshaped coil fields would also be different from one machine to another of the same manufacturer; not to mention from one maker to another. All misshaped fields are not created equal.

 

[findit]

Hey EASYMONEY, some of us enjoy learning and find your posts very informative. thanks.

"your only as smart as you are educated"

 

[EasyMoney]

Hey ShortStack.

I for one DO understand and appreciate your short description of guidance and alignments, because I worked for the Department of Defense in Keyport, Washington on the Electronic Command Control and Guidance Systems for the Mark 48 Nuclear Powered Torpedo Systems in engineering and R&D, but as you well know, I normally use very simple terms here and in all my writings so as to make sure that most people people don't have trouble grasping certain things. I could use vector systems, algorithms, linear algebra, quadratics, quantum mechanics theory, etc, and in 5 different languages all at the same time if I wanted to, but only a small handful of people would even know a smidge of what the heck I was saying.

I was not intending to create any negative remarks about your inference as to "cones", I was merely trying to pass on some valuable information that I felt people could use somehow.

As in the case of my experiences in case I wanted to describe how a torpedo can drive itself and to where and how, with nobody manning it, wouldn't be very useful here in a metal detecting forum anyway, well, at least for the most part , save for a certain few examples, so I try to not bring all that vaguely related stuff into this place. Besides that it would be treason if I did anyway.

In all truthfulness, I learn a lot more by reading, watching and listening than I do by speaking, writing, or telling, but there are times when I feel a need to inform instead of quietly sitting on the side wishing tht I would feel a bit more comfy speaking up and out when I see a chance to help someone. At times I do write as if I am an 8 year old, but at times I want to pass on some more substantial and /or beneficial info too. As for me, I consider that I have learned as much from pure idiots who cannot spell or think or read, as I have from some people who have Phd's in mechanical engineering. I listen to all and I never try to put a personal or negative attack on anybody who is merely wanting to add to a discussion, and it's not because I'm being politically correct either, It's just because I'mgiving credit where credit is due, nothing more, nothing less.

Thanks for the friendly reply ShortStack. I consider your input and comments valuable.

Thanks Findit. And as you already well know your voice is also well-appreciated in my little world.

You all have a nice time tomorrow chasing for that elusive $5 gold coin. I will too.

EasyMoney

 

[Shortstack]

I hope you find TWO of em, EasyMoney.

 

[MD Dog]

Wow it's like a geek fight in here. Sorry I admit I know nuttin and I like it that way. I've always held that you don't need a deeper detector, just deeper research. Can't find what aint there. But enough of my hillbilly axioms. Any chance one of you electronic types can tell me straight up. Does using my 12" coil on my Ace 250 Give me more depth or just a wider feild ?

 

[Shortstack]

Wow it's like a geek fight in here. Sorry I admit I know nuttin and I like it that way. I've always held that you don't need a deeper detector, just deeper research. Can't find what aint there. But enough of my hillbilly axioms. Any chance one of you electronic types can tell me straight up. Does using my 12" coil on my Ace 250 Give me more depth or just a wider feild ?

"Geek fight". ROFLMAO !!!!!!!!!!!!!!!!

 

[pastorals]

It is a real pleasure to be able to read posts that are interesting, helpful and thoughtful.. I am new to MD'ing so I read many, many posts here, trying to learn as much as I can and I am happy to say my explorations have been profitable. Now, if the truth be known, not everything I've read has been helpful. When trying to determine which detector I would buy to use in starting my adventure I heard way too many "words of wisdom" that were purely emotional cheerleading. But I did find enough honest evaluations of different detectors to enable me to, finally, make a decision.I chose a Tesoro Vaquero as my first machine (haven't gotten it yet). You may agree or disagree with my choice. So be it. It has been decided.

I would just like to add that the conversation on this thread was outstanding. My compliments to the "teachers".

Alan

 

[Treasure_Hunter]

It is a real pleasure to be able to read posts that are interesting, helpful and thoughtful.. I am new to MD'ing so I read many, many posts here, trying to learn as much as I can and I am happy to say my explorations have been profitable. Now, if the truth be known, not everything I've read has been helpful. When trying to determine which detector I would buy to use in starting my adventure I heard way too many "words of wisdom" that were purely emotional cheerleading. But I did find enough honest evaluations of different detectors to enable me to, finally, make a decision.I chose a Tesoro Vaquero as my first machine (haven't gotten it yet). You may agree or disagree with my choice. So be it. It has been decided.

I would just like to add that the conversation on this thread was outstanding. My compliments to the "teachers".

Alan

Alan, if you become a charter member you can use the search function available to charter members that allows you to search all posts for key words..... Makes it easy to find a mod, or question about a certain model.. One of the features of CM and well worth the cost of CM....