New Metal Detector Book!

[Qiaozhi]

Carl and I are proud to announce that we have successfully completed the writing of a technical book on metal detector technology.

This is the first in-depth book on this subject since 1927; and it feels like we've been working on it for that long! Countless hours have gone into the production of this book, not only writing, but building and testing the many projects, sometimes multiple times.

Inside the METAL DETECTOR

ISBN 978-0-9858342-0-3
Publication date: September 2012
300 pages

$34.95 - available directly from Geotech.

Here is the Table of Contents to whet your appetite:

Introduction

Chapter 1: History of the Metal Detector
The People
The Applications
The Companies

Chapter 2: The BFO Principle

Chapter 3: Designing a BFO Detector
Reference Oscillator Design
Search Oscillator Design
Mixer and Detector Design
Headphone Amplifier
The Complete BFO Detector
Using Oscillator Harmonics
Construction Details

Chapter 4: A Simple Probe That Works!
Search Oscillator
Automatic Tracking Circuit
Construction Details

Chapter 5: Induction & Coils
Magnetic Fields
Induction
Induction Balance
Eddy Currents
Search Coils
Mineralization Effects

Chapter 6: Principles of Induction Balance
Transmit Frequency
What the Experts Say
So What's Best?
Power Supply
Evaluation of Initial Design Decisions

Chapter 7: Target Discrimination
Phase Demodulation
Motion Versus Non-motion
Discrimination With an Analog Detector

Chapter 8: Transmit-Receive Detector
Transmit Oscillator
RX Amplifier
Audio Output
Power Supply
Testing
Construction Details

Chapter 9: Designing an IB Detector
Aconyms
Stabilized Power Supply
Transmit Oscillator
Receiver Preamp
Designing a VLF IB Detector with GEB
GEB and DISC sampling
CMOS Analog Switches
Motion Mode of Detection
Audio Oscillator, Chopper and Amplifier
A Little More Info On Discrimination
Automatic Battery Check Circuit
Battery Pack
The Completed Prototype
Initial Setup Procedure
Real World Testing
But Can We Do Better?
Improving the Design
Comparator Operation
Detector Calibration
Real World Testing (again)
In Conclusion
Construction Details

Chapter 10: IB Coil Experiments
Experiment #1: MD-3030 10" Concentric Coil
Experiment #2: Fisher M-scope 11" Concentric Coil
Experiment #3: Garrett Crossfire 8" Concentric Coil
Experiment #4: Troy 9" Concentric Coil
Experiment #5: Viking 6DX Double-D Coil
Constructing Homemade IB Coils
Double-D Coil Experiment
Double-O Coil Experiment
Concentric Coil Experiment
Omega Coil Experiment
Conclusion
Step-by-Step Instructions for Constructing a DD Coil

Chapter 11: Pulse Induction Principles
PI Transmit
PI Front End
Sampling
Digging in Deeper

Chapter 12: Pulse Induction Designs
PI Design 1
PI Design 2
PI Design 3
PI Design 4
Bonus: PI Design 5
Advanced Topics
Power Supply
Preamp
Sampling
Ground Balance
Coils
Really Advanced Topics
Construction Details --- PI-1
Construction Details --- PI-2
Construction Details --- PI-3
Construction Details --- PI-4

Chapter 13: Long Range Locators
Dowsing
History
Reactions
Why Dowsing "Works"
Dowsing Tests
Empirical Results
Summary
LRLs
"Passive" LRLs
"Active" LRLs
MFD Theory
Summary
Treasure Auras
Photographing Treasure Auras

Chapter 14: Pistol Detector
Ferrite Receiver
TX Circuit
The Sky and Compass Effects
Detecting the Anomaly
The Front Panel Controls
TR Mode of Operation
Nulling the Ferrite Coil
But Does it Actually Work?
Meaning of TOTeM
Construction Details
Conclusion

Chapter 15: Loose Ends
Multi-frequency Design
Myths & Fallacies
Is it an antenna?
The Halo Effect
Metal or Plastic Stem Bolt?
Electrostatic Shielding
Power Output
Coil Sensitivity
The Concentric Ring Experiment
Component Marking Standard
Electromagnetic Terminology
PC Boards

Appendix A: Air-Cored Coil Calculator
The Visual Basic Version
The Tcl/TK Version
The Javascript version
Accuracy

Appendix B: Resources
Web Sites
Books
Magazine Articles
Patents

Index

[aft_72005]

Hi Qiaozhi
As I read in introduction, seem it is complete book .
My congratulation to you and carl . http://www.getsmile.com/emoticons/funny-smileys-68129/clap.gif
Best regards

[Geo]

Hi Qiaozhi.
Will you sell it in electronic format??? It is better because we can use translator for unknown words:lol:.
Congratulation to u and to Carl

:):)

[Barbarossa]

very good work.congratulations

[Goldmaxx]

Hi Qiaozhi
my congratulation to you and Carl. The book looks very good and is certainly very interesting.
The book is a great work. I would buy the book very much.
I live in Germany and would like to know if I can order it somewhere in Iternet, or can I the book directly order from you?

sorry for my bad english.

Best regards

[Qiaozhi]

Ordering instructions for the UK, Europe and surrounding countries:

UK - the total cost will be £24, which includes the book + P&P.
Delivery should take around 3 days.

Europe - the cost will be £28, which includes the book + P&P.
Delivery should take around 5 days.

Non-European countries - please ask for a price, although in most cases it will be the same cost as Europe.

I am currently waiting delivery of 100 padded jiffy bags. When these arrive, the books will be dispatched.

Paypal to qiaozhi@geotech1.com

For the Americas, Asia and Oz, Paypal to carl@geotech1.com. Shipping is a flat $4 in the US, for anywhere else the cost of shipping will need to be calculated, and it may be pricey because postal rates have gone into orbit.

When you purchase by Paypal, your delivery address is automatically sent, so the ordering process should be very straightforward.

In the near future Carl will be moving the book ordering information to a dedicated area on Geotech.

[Qiaozhi]

Hi Qiaozhi.
Will you sell it in electronic format??? It is better because we can use translator for unknown words:lol:.
Congratulation to u and to Carl

:):)
There are no plans to offer the book in electronic format. It's just too open to abuse.
Sorry.

If you purchase the book and then find some of the words difficult, you only have to ask here on the forum. We will be pleased to help.

[Qiaozhi]

Hi Qiaozhi
my congratulation to you and Carl. The book looks very good and is certainly very interesting.
The book is a great work. I would buy the book very much.
I live in Germany and would like to know if I can order it somewhere in Iternet, or can I the book directly order from you?

sorry for my bad english.

Best regards
Please see the ordering information (previous post).
It will be £28 for Germany, which includes the book + P&P.

To order by Paypal:


Log in to Paypal
Select "Send Money"
Enter email: qiaozhi@geotech1.com
Enter amount: 28
In pull-down box, select "GBP - British Pounds"
Select "Purchase" tab
Tick the "Goods" radio button
Select "Continue", etc.

[Geo]

Qiaozhi be sure for the p&p to Greece and tell me. Maybe post to Greece to be more expensive.

:)
btw... the book has any biography and photo from you????

[Qiaozhi]

Qiaozhi be sure for the p&p to Greece and tell me. Maybe post to Greece to be more expensive.

:)
btw... the book has any biography and photo from you????
The cost is the same as for Europe, as I don't think you've quit the European Union just yet. ;)
So the total cost is £28, which includes the book + P&P.

No biography from either Carl or myself. The technical stuff took up all the available space. Anyway, it's about metal detecting technology, not about us. :)

[Geo]

The cost is the same as for Europe, as I don't think you've quit the European Union just yet. ;)
So the total cost is £28, which includes the book + P&P.

No biography from either Carl or myself. The technical stuff took up all the available space. Anyway, it's about metal detecting technology, not about us. :)

Yes, but always the readers want to learn about the authors!!!!:lol::lol:
Anyway i ordered the book so now is your job ..:lol::lol:

Regards:)

[Qiaozhi]

Yes, but always the readers want to learn about the authors!!!!:lol::lol:
Anyway i ordered the book so now is your job ..:lol::lol:

Regards:)
Thanks Geo!
When the packaging arrives I will dispatch the book immediately and let you know it's on its way.

[Geo]

Thanks Geo!
When the packaging arrives I will dispatch the book immediately and let you know it's on its way.

Hi Qiaozhi.
Thanks for all, i would highly appreciate if there was in the book a very brief biography of George Overton :lol::).
I am sure that this book is a kind of encyclopedia on metal detectors although i am not sure what writes about pistol detector. :lol:

My Regards

[Qiaozhi]

Hi Qiaozhi.
Thanks for all, i would highly appreciate if there was in the book a very brief biography of George Overton :lol::).
I am sure that this book is a kind of encyclopedia on metal detectors although i am not sure what writes about pistol detector. :lol:

My Regards
Wait and see ... ;)

[Goldmaxx]

Hi Qiaozhi

Many thanks for the ordering instructions.
I'll order the book quickly. :)

Best regards

[Qiaozhi]

Hi Qiaozhi

Many thanks for the ordering instructions.
I'll order the book quickly. :)

Best regards
Thanks. Order received. :thumb:

My stock of books is running out fast! Only a hand-full left.

The books will be supplied on a first-come first-served basis. When my current stock is exhausted, there will possibly be a week or two delay before I receive the next shipment.
Everyone who has placed an order so far is guaranteed a book from the current stock. I will make another post when the ones I have are sold. You will still be able to order, but please be aware that there will an additional delay.

[J_Player]

Hi Qiaozhi and Carl,
Congratulations on your first book!
It's good to see you two actually did it.
From what I see in the table of contents, this is bound to be the definitive source of reliable information about how metal detectors work, written by the foremost engineers in the world of metal detecting.

Considering that this book draws on all the brilliant contributions that we see in the Geotech forum, as well as the years of experience you and Carl have in designing and building metal detectors, there probably is no other book about metal detecting to compare. Who else could write such a book, other than electronic engineers who are surrounded by metal detector forum topics, questions, circuits, and all that goes with it?

With any luck, the proceeds from selling this book will pay for the geotech forum and the LRL annex for years to come, and then some. The best news is this is the first thing I have seen advertised in the LRL forum that I am certain is not a fraud! The price is no where near 1000 euros, and what we get for our money is pure quality, nothing else. I will be sending my order to the USA outlet as soon as I get a chance to set up paypal. Hopefully we can get an autographed edition, considering we are online forum contributors... :D


Congratulations again! :)
J_P

[WM6]

I can only sign J_P words - in happy expectation this book coming in my library.

[Geo]

I'm afraid we will have many discussions in lrlforum about Chapter 14. I'd like to see something MORE than those written in the RS forum. I await eagerly the arrival of the book ..

:):)

[Qiaozhi]

I'm afraid we will have many discussions in lrlforum about Chapter 14. I'd like to see something MORE than those written in the RS forum. I await eagerly the arrival of the book ..

:):)
Oh yes ... there's definitely something new. ;)

[Geo]

Maybe our answers to be the begining for the second edition of the book!!!!
:lol::lol:

[Geo]

I took the book before 3 days.
Very good with a new PD inside designed by Carl or Qiaozhi or both:lol:.
But i am sure that this PD don't work.....
If Alonso will see it .... he will :lol::lol::lol::lol:

Regards:)

[Qiaozhi]

I took the book before 3 days.
Very good with a new PD inside designed by Carl or Qiaozhi or both:lol:.
But i am sure that this PD don't work.....
If Alonso will see it .... he will :lol::lol::lol::lol:

Regards:)
It depends what you mean by "work". ;)

Obviously it does actually function as an electronic detector, but whether it's detecting some emanation from longtime buried gold may be open to debate. Also, it does work as a short range metal detector.

Have you built it?

[Qiaozhi]

The next shipment of books has arrived! http://www.geotech1.com/forums/images/smilies/smilies/cheers.gif

I will posting out all pending orders today.

[nelson]

Hi Qiaozhi

First of all i congratulate you and Carl for the book you are realising.

Now i just want to have one book, so please give full buying details to place an order, plus shipping cost to Santiago Chile SA.
I will pay by paypal

Regards

Nelson

The next shipment of books has arrived! http://www.geotech1.com/forums/images/smilies/smilies/cheers.gif

I will posting out all pending orders today.

[Geo]

It depends what you mean by "work". ;)

Obviously it does actually function as an electronic detector, but whether it's detecting some emanation from longtime buried gold may be open to debate. Also, it does work as a short range metal detector.

Have you built it?

I did not build it, but if you read carefully you will understand that don't work as LRL.

:)

[Dave J.]

BOOK REVIEW (after a fairly quick read)

For anyone thinking that with no knowledge of electronics they're going to be building a working metal detector, that would be the wrong thing to think. You need to learn basic electronics elsewhere, there's no need for Carl and George to waste time on that, their expertise is metal detectors. There is however some brief explanation of those electronic fundamentals which are especially important to metal detection which electronic techs and engineers in other disciplines may not be familiar with.

The history section is excellent, a wonderful read. Many flaws of omission and commission but that's as good as it gets in this business. This is metal detectors we're talking about, it's not like world wars where there were thousands of reporters trying to document everything for posterity and a researcher can go back through the newspaper morgues and piece it all back together. And it's not like this book was a work expected to earn the publisher a million dollars and thus could warrant tens of thousands of research hours. The authors have nonetheless gone through a great pile of disconnected source material in an attempt to piece together a grand story of "the evolution of beep". Although that story has many minor errors and many omissions (and a few major), the history of beep that you find in this book is as good as it's ever going to get. Nobody's going to do it better, this is the standard.

The part on metal detection technological theory and practice is good as far as it goes. Anyone who is hoping to glean the latest trade secrets from the book will be disappointed. I found the explanations of technology to be quite sound as far as they went, with virtually no areas of disagreement. No surprises on that score, look who the authors are!

If you're trying to home-brew a metal detector, the "latest trade secrets" aren't necessary anyhow, what you need is the basics and the patience to do them well. There are machines designed 15-30 years ago which can acquit themselves quite well in performance comparisons with machines being produced today-- in fact some of those oldies are still popular despite the lack of newfangled revisions.

The project schematics section, I found that a bit disappointing. It all seemed so 1970's. Reality check: I'm fortunate enough to be in a situation where I can order the latest components online in the afternoon and have them in my hand by noon the next day. There are many places in the world where it's hard to get parts, especially new stuff, and everywhere on the planet it's easier to build one-offs with through-hole components than with surface mount components. In that context, designs that look 20-30 years or more out of date are more relevant to the average experimenter around the planet than a design done a year ago by a major manufacturer would be. Heck, even nowadays if there's something I have to throw together in a hurry, my first concern is "is this a design I can solder onto a perfboard?" There's a lot of stuff that can be done well with parts that were available 20 or more years ago.

Want to build an LRL? One could argue that the subject of LRL's doesn't deserve air time on other forums much less books, but there it is. This is all hand in glove with the changes that are going on with the URL itself.

There's also a patent section. Sorry, haven't had time to plow through that yet.

--Dave J.

[Qiaozhi]

Thanks for the review Dave. :cool:

As you rightly pointed out, the designs in the book are not cutting edge, and that was (in fact) the intention.
Here is a short quote from the book:

------------------------------------------
This is one of those books where you could keep on writing and writing, and never get finished. At some point you have to draw a line in the sand and say, "This is where we stop." In doing so, there will be a lot of information that never gets discussed, or topics that only receive elementary coverage.
------------------------------------------

We had to walk a thin line between making a Dummies Guide to Metal Detector Technology and a dry academic text. In the end we went for an easy conversational style of writing to cater for most levels of technical knowledge encountered on the Geotech forums. There is also the problem of language, as we often see in online posts. A decision was also made (in the project-based chapters) to not cater for readers with no, or very little, electronics knowledge. Basically, if you struggle with Ohm's Law then you're in trouble.

Hopefully we got the balance about right.

I did mention the possibility of a second book to Carl, where we can address the obvious holes and discuss more detailed technical information. His first response was, "Are you mad?". I think he's still trying to recover from the problems of actually getting it published. :D

[Geo]

BOOK REVIEW (after a fairly quick read)

For anyone thinking that with no knowledge of electronics they're going to be building a working metal detector, that would be the wrong thing to think. You need to learn basic electronics elsewhere, there's no need for Carl and George to waste time on that, their expertise is metal detectors. There is however some brief explanation of those electronic fundamentals which are especially important to metal detection which electronic techs and engineers in other disciplines may not be familiar with.

The history section is excellent, a wonderful read. Many flaws of omission and commission but that's as good as it gets in this business. This is metal detectors we're talking about, it's not like world wars where there were thousands of reporters trying to document everything for posterity and a researcher can go back through the newspaper morgues and piece it all back together. And it's not like this book was a work expected to earn the publisher a million dollars and thus could warrant tens of thousands of research hours. The authors have nonetheless gone through a great pile of disconnected source material in an attempt to piece together a grand story of "the evolution of beep". Although that story has many minor errors and many omissions (and a few major), the history of beep that you find in this book is as good as it's ever going to get. Nobody's going to do it better, this is the standard.

The part on metal detection technological theory and practice is good as far as it goes. Anyone who is hoping to glean the latest trade secrets from the book will be disappointed. I found the explanations of technology to be quite sound as far as they went, with virtually no areas of disagreement. No surprises on that score, look who the authors are!

If you're trying to home-brew a metal detector, the "latest trade secrets" aren't necessary anyhow, what you need is the basics and the patience to do them well. There are machines designed 15-30 years ago which can acquit themselves quite well in performance comparisons with machines being produced today-- in fact some of those oldies are still popular despite the lack of newfangled revisions.

The project schematics section, I found that a bit disappointing. It all seemed so 1970's. Reality check: I'm fortunate enough to be in a situation where I can order the latest components online in the afternoon and have them in my hand by noon the next day. There are many places in the world where it's hard to get parts, especially new stuff, and everywhere on the planet it's easier to build one-offs with through-hole components than with surface mount components. In that context, designs that look 20-30 years or more out of date are more relevant to the average experimenter around the planet than a design done a year ago by a major manufacturer would be. Heck, even nowadays if there's something I have to throw together in a hurry, my first concern is "is this a design I can solder onto a perfboard?" There's a lot of stuff that can be done well with parts that were available 20 or more years ago.

Want to build an LRL? One could argue that the subject of LRL's doesn't deserve air time on other forums much less books, but there it is. This is all hand in glove with the changes that are going on with the URL itself.

There's also a patent section. Sorry, haven't had time to plow through that yet.

--Dave J.

I can't understand why you apology for Carl and Qiaozhi????

[Carl-NC]

Thanks for the feedback Dave. I did the history section, based on what bits & pieces I could glean from old magazines and old forum posts. I'll gladly accept any add'l insight you can offer. Second Edition.

You're absolutely right about the "dated" projects, and one of the reasons why. We decided on these projects because (1) they demonstrate basic detector operation and (2) of easy availability of parts. We avoided cutting edge due to time constraints and my own desire to avoid issues with my boss. Boss liked what we did so Second Ed will likely dive a bit deeper.

The LRL section was included because I thought it important to get this information in proper published format once & for all. I have enough mat'l for an independent book and may spin this off and out.

- Carl

[Geo]

I believe that you have not any problem about my review for the LRL section!!!!!

[hung]

Hi Geo, I can't believe you wasted your money on this thing.
You know more about metal detecting and most important, you experience much more about metal detecting than both of the 'authors' altogether.

What would you expect to find in this 'readout' other than 'floor polishers' conventional material?
And what would you expect to find in the supposed 'LRL section' other than...
'floor polishers' conventional material?

[Geo]

Hi Hung.
Carl and Qiaozhi made very good work in this book. In section about LRLs they tried to explain how PD works......
It is very difficult to understand how it works if you do not make it to work as lrl and to locate objects from long distance. Everyone must going inside the mind of Alonso if he wants a workable lrl.

Regards:)

[Qiaozhi]

Hi Hung.
Carl and Qiaozhi made very good work in this book. In section about LRLs they tried to explain how PD works......
It is very difficult to understand how it works if you do not make it to work as lrl and to locate objects from long distance. Everyone must going inside the mind of Alonso if he wants a workable lrl.

Regards:)
Thanks Geo.

As you have seen (unlike our friend Hung, who is making huge assumptions without even reading the book) that we did our best in Chapter 13 to describe the current "state of the art" concerning LRLs. You might not agree with our conclusions, but that is your prerogative.

In Chapter 14 we kept an open mind and attempted to create a PD based on knowledge available in the public domain. This is the TOTeM project. In real world tests it does seem to exhibit the same characteristics as the Alonso PD, and basically it comes down to whether you believe it is detecting emanations from longtime buried treasure, or simply reacting to electromagnetic interference. It is an interesting project to build, and I think you would be surprised, if you were to build it. ;)

[Geo]

So is the project for the winter.
I will try to build it!!!
Results.... next year.

Regards:)

[Qiaozhi]

So is the project for the winter.
I will try to build it!!!
Results.... next year.

Regards:)
I wish you luck, and may you be the first to find treasure with it. :ninja:

[hung]

Hi Hung.
Carl and Qiaozhi made very good work in this book. In section about LRLs they tried to explain how PD works......
It is very difficult to understand how it works if you do not make it to work as lrl and to locate objects from long distance. Everyone must going inside the mind of Alonso if he wants a workable lrl.

Regards:)

Well Geo, it's up to you what you choose and do with your money. Considering their 'technical posts' for years in this forum, I wouldn't even waste my time reading this thing for free.
Since you and others who ordered that thing became their quickest solution to pay this month's rent, you folks are now their valuable piece of gold.
Build their LRL or whatever that thing might be and go find treasure. Have fun.

No Alonso is not the only one who knows how to make LRLs. There are 3 people in this forum (excluding the ones that keep posting) who did a wonderful job. Now they only watch posts with a certain 'grin' and a pit of 'secrecy'. No involvement.

Bye for now. Heading to the field.
Take care.

[Goldmaxx]

Hi Qiaozhi

The book arrived yesterday and I am absolutely thrilled.
Thank you, that was all so quick and easy :cheers:
So I must say, this is a very good job. Congratulations to you and Carl
In Germany they would say "das Buch ist saugeil". :lol::lol::lol:
The chapter on PD I find very interesting and will build it also.
Even if it should not work, it is interesting to experiment with it.

Hi Geo,
maybe you've got a PD what works for me? ;):lol:

Best regards

[Geo]

Well Geo, it's up to you what you choose and do with your money. Considering their 'technical posts' for years in this forum, I wouldn't even waste my time reading this thing for free.
Since you and others who ordered that thing became their quickest solution to pay this month's rent, you folks are now their valuable piece of gold.
Build their LRL or whatever that thing might be and go find treasure. Have fun.

No Alonso is not the only one who knows how to make LRLs. There are 3 people in this forum (excluding the ones that keep posting) who did a wonderful job. Now they only watch posts with a certain 'grin' and a pit of 'secrecy'. No involvement.

Bye for now. Heading to the field.
Take care.

Hi Hung.
For me is not waste of time to read a technical book, especially this book. I don't know everything so there are new things inside it. Now about lrl... there are many lrls who works but the problem is near to the objects. This is the reason that i like the pistols from Alonso because have the ability to pinpoint (when the conditions are good and they work).

Regards :)

[Geo]

Hi Qiaozhi

The book arrived yesterday and I am absolutely thrilled.
Thank you, that was all so quick and easy :cheers:
So I must say, this is a very good job. Congratulations to you and Carl
In Germany they would say "das Buch ist saugeil". :lol::lol::lol:
The chapter on PD I find very interesting and will build it also.
Even if it should not work, it is interesting to experiment with it.

Hi Geo,
maybe you've got a PD what works for me? ;):lol:

Best regards


Hi Goldmaxx.
Sorry but i have not a PD for you:frown:

Regards:)

[Qiaozhi]

In Germany they would say "das Buch ist saugeil". :lol::lol::lol:
That's funny! :D
The chapter on PD I find very interesting and will build it also.
Even if it should not work, it is interesting to experiment with it.
Exactly. :thumb:
I look forward to hearing your experiences.

[Qiaozhi]

... I wouldn't even waste my time reading this thing for free.
I will post a short quote from Chapter 14, regarding tests made with the TOTeM, so you can see what you're missing:

------------------------------------------
Does it work as a metal detector? At least in the active mode at short range, the answer is yes. When used in the active medium range mode there are definitely signals being detected, and you can even occasionally appear to be following a "signal line". In the passive long range mode the same can be said to be true, and it certainly acts like a sensitive electromagnetic field detector.
But does it detect treasure (in particular, gold) at long or even medium distance? Well, that is the big question. From a skeptical point of view the answer is almost certainly no, but the intention was to keep an open mind during the development of this device.
------------------------------------------

How open is your mind? :shrug:

[Carl-NC]

...I wouldn't even waste my time reading this thing for free.

Hung, I urge you not to read it. In fact, if you order a copy I'll decline your order. I sure don't want you to actually learn anything, it would take all the fun out of your posts.

Yep, we're making money hand-over-fist on this book. 10 yrs and $1000's invested, and I've already made over $200!

- Carl

[Goldmaxx]

Hi Qiaozhi
Thank you. I will keep you up to date.
it may be that I have to ask you questions about this project.
I hope it's okay with you. :)
I've never built something and am really looking forward to the results.

Hi Geo,
It is a great pity, could have been. ;):)

Best regards

[Qiaozhi]

Hi Qiaozhi
Thank you. I will keep you up to date.
it may be that I have to ask you questions about this project.
I hope it's okay with you. :)
I've never built something and am really looking forward to the results.

Hi Geo,
It is a great pity, could have been. ;):)

Best regards
No problem.
All the construction details are given in the book, but if anything is not completely clear, then please ask.

[J_Player]

Hi Hung.
Carl and Qiaozhi made very good work in this book. In section about LRLs they tried to explain how PD works......
It is very difficult to understand how it works if you do not make it to work as lrl and to locate objects from long distance. Everyone must going inside the mind of Alonso if he wants a workable lrl.

Regards:)Hi Geo,
I also think this was a good work.
I tried to get inside the mind of Alonso as you say we must, but the concept of using a hidden transmitter is really not part of metal detecting theory or LRL theory.
Maybe better to stick to real metal detectors... don't you think so?

Best wishes,
J_P

[Geo]

Hi J_P.
You never will to go inside the mind of Alonso because you have a problem.... you forget very soon. You forget the small gold objects that robalocarapanda found with mineoro http://www.longrangelocators.com/forums/showpost.php?p=143208&postcount=127 .... you forget the coins that Morgan found with mineoro http://www.longrangelocators.com/forums/showpost.php?p=143213&postcount=131, you forget the gold chain who found Jimmys, you forget MIJ who locate the burriet coins with pdk http://www.longrangelocators.com/forums/showpost.php?p=143356&postcount=1 ...., you forget..........
It is time to remember some occasions where designs by Alonso found hidden objects.

Regards:)

[J_Player]

Hi J_P.
You never will to go inside the mind of Alonso because you have a problem.... you forget very soon. You forget the small gold objects that robalocarapanda found with mineoro http://www.longrangelocators.com/forums/showpost.php?p=143208&postcount=127 .... you forget the coins that Morgan found with mineoro http://www.longrangelocators.com/forums/showpost.php?p=143213&postcount=131, you forget the gold chain who found Jimmys, you forget MIJ who locate the burriet coins with pdk http://www.longrangelocators.com/forums/showpost.php?p=143356&postcount=1 ...., you forget..........
It is time to remember some occasions where designs by Alonso found hidden objects.

Regards:)I did not forget those.
But I know the mind of Alonso did not locate them.
These were located by people who do not use hidden transmitters.
Don't you remember?
Alonso went to the same location as robalocarapanda, and only Alonso and his assistant had the mind to use a hidden transmitter.
Everyone else at that location had the mind to use only treasure hunting equipment.

Best Wishes,
J_P

[WM6]

Today I received a book.

Excellent reading for us LRL enthusiast.

One who wish to go step forward to real LRL need to consider this book as must read.

Thanks Carl and Qiaozhi.

[Qiaozhi]

Today I received a book.

Excellent reading for us LRL enthusiast.

One who wish to go step forward to real LRL need to consider this book as must read.

Thanks Carl and Qiaozhi.
That's good to know.
The book was posted at lunchtime on Thursday 27th September, so it arrived in about 4 working days (including Saturday). Bravo to the postal system. :thumb:

[Agraz]

Congratulations, with who I go to purchase the book mentioned? There is a link on the Internet? I want to be dedicated by / authors. My full name is Jose Antonio Agraz Sandoval, Thank you.

[J_Player]

Congratulations, with who I go to purchase the book mentioned? There is a link on the Internet? I want to be dedicated by / authors. My full name is Jose Antonio Agraz Sandoval, Thank you.This book is secret. The people who sell it do not want you to know where you can buy it.
But if you really want to buy this book, you can go here to get it: http://www.geotech1.com/forums/content.php?125-inside-the-metal-detector

Abrazos,
Best wishes,
J_P

[Qiaozhi]

Congratulations, with who I go to purchase the book mentioned? There is a link on the Internet? I want to be dedicated by / authors. My full name is Jose Antonio Agraz Sandoval, Thank you.

This book is secret.
Actually, it's not meant to be a secret. I will add a link in the LRL forum later today to make it easier to find.
http://www.geotech1.com/forums/content.php?125-inside-the-metal-detector

[Agraz]

hello, thank you, I hope to open a PayPal account, while I put your add in the forum of my country, I hope you do not bother, for the secret ...

http://www.buscadores-tesoros.com/t11370-libro-tecnico-en-ingles#126009

[Qiaozhi]

hello, thank you, I hope to open a PayPal account, while I put your add in the forum of my country, I hope you do not bother, for the secret ...

http://www.buscadores-tesoros.com/t11370-libro-tecnico-en-ingles#126009
Thanks. :thumb:

[Geo]

Hi.
At page 213 of your book you write that the Mineoro FG80 is tuned around to 433Mhz.
It is not right, the frequency that it is tuned is around to 100Khz.
So you can edit it at a new version....

Regards

[Qiaozhi]

Hi.
At page 213 of your book you write that the Mineoro FG80 is tuned around to 433Mhz.
It is not right, the frequency that it is tuned is around to 100Khz.
So you can edit it at a new version....

Regards
Hi Geo,

Carl owns a Mineoro FG80, and he found in testing that it was tuned to around 433MHz. Is it possible that there is some variation between models?

I will leave it to Carl to comment on this one.

[hung]

Hi Geo,

Carl owns a Mineoro FG80, and he found in testing that it was tuned to around 433MHz. Is it possible that there is some variation between models?

I will leave it to Carl to comment on this one.

:lol: Jeezz... Not even the frequency this poor fella got right. Imagine what's in the rest of his 'book' about it.
Amusing.

Y'all have a nice weekend. I certainly will.

[Geo]

Hi Geo,

Carl owns a Mineoro FG80, and he found in testing that it was tuned to around 433MHz. Is it possible that there is some variation between models?

I will leave it to Carl to comment on this one.

Last month i opened 2 Mineoro for repair and i measured the frequency. They was one DC2008 and one FG80. Both has the same pcbs and exactly the same components except that the FG80 has one IR led at the front side. Also they are tuned at different frequence, one at 133Khz and the other near to 100Khz.
Maybe Carl remember from older models who had an transmitter at 433Mhz for the wireless headphones.
Regards:)

[Qiaozhi]

:lol: Jeezz... Not even the frequency this poor fella got right. Imagine what's in the rest of his 'book' about it.
Amusing.
Perhaps you should have waited for Geo's reply before jumping in with both feet. :rolleyes:

Last month i opened 2 Mineoro for repair and i measured the frequency. They was one DC2008 and one FG80. Both has the same pcbs and exactly the same components except that the FG80 has one IR led at the front side. Also they are tuned at different frequence, one at 133Khz and the other near to 100Khz.
Maybe Carl remember from older models who had an transmitter at 433Mhz for the wireless headphones.
Regards:)
Thanks Geo. I seem to remember Carl telling me that he was able to trigger the Mineoro FG80 with his garage door opener.

[Silvino]

Congratulations Carl and Qiaozhi!
The book is amazing!
It's a invaluable source of good information!
Also, I'm sure most people here will like the chapter 13!

Silvino.

[Qiaozhi]

Congratulations Carl and Qiaozhi!
The book is amazing!
It's a invaluable source of good information!
Also, I'm sure most people here will like the chapter 13!

Silvino.
Actually, I'm surprised more people here are not interested in Chapter 14. :ninja:
All except Hung, that is ... as he's not allowed to have a copy, just in case he might learn something. :lol:

[J_Player]

Perhaps you should have waited for Geo's reply before jumping in with both feet. :rolleyes:

Thanks Geo. I seem to remember Carl telling me that he was able to trigger the Mineoro FG80 with his garage door opener.I remember reading several times in treasurenet forums where Carl and others were able to trigger Mineoro locators with garage door openers, amongst other electronic transmitting devices.

http://www.treasurenet.com/forums/geophysics/98039-mineoro-dc2007-questions.html#post1029526
http://www.treasurenet.com/forums/techniques/106216-gold-locator.html#post1122616
http://www.treasurenet.com/forums/mississippi/98785-no-gold-yet-mineoro.html#post1036219


Best Wishes,
J_P

[Sneshko]

Today I received my copy of "Inside The Metal Detector" by George & Carl.
From England to Serbia traveled 12 days. Eh! Post, post ...
For me as a beginner in electronics - the book is excellent.
However, professionals may find it interesting detail.
George and Carl did a great job. Congratulations!
Of course, I will first try to close The TOTem PD.
Qiaoshi & Carl thanks for this very interesting book!
Regards!
Sneshko

[Qiaozhi]

Today I received my copy of "Inside The Metal Detector" by George & Carl.
From England to Serbia traveled 12 days. Eh! Post, post ...
For me as a beginner in electronics - the book is excellent.
However, professionals may find it interesting detail.
George and Carl did a great job. Congratulations!
Of course, I will first try to close The TOTem PD.
Qiaoshi & Carl thanks for this very interesting book!
Regards!
Sneshko
I'm pleased it arrived safely. :thumb:
Enjoy!

[daryo]

nice book

[Morgan]

Today I received my copy of "Inside The Metal Detector" by George & Carl.
From England to Serbia traveled 12 days. Eh! Post, post ...
For me as a beginner in electronics - the book is excellent.
However, professionals may find it interesting detail.
George and Carl did a great job. Congratulations!
Of course, I will first try to close The TOTem PD.
Qiaoshi & Carl thanks for this very interesting book!
Regards!
Sneshko


I saw the TOTeM PD project,seems good electric field locator 65 to 75 KHz, i´m surprized that someone said it can locate the 1,5V spark at 3 meters .
Maybe better than PDK ???
When i have time i go to build the TOTeM. i will make the field test ,see the results,and post here.

[Morgan]

I saw the TOTeM PD project,seems good electric field locator 65 to 75 KHz, i´m surprized that someone said it can locate the 1,5V spark at 3 meters .
Maybe better than PDK ???
When i have time i go to build the TOTeM. i will make the field test ,see the results,and post here.

The shape of the TOTem is realy like a indian TOTEM,but the important is the field test.

[Geo]

I saw the TOTeM PD project,seems good electric field locator 65 to 75 KHz, i´m surprized that someone said it can locate the 1,5V spark at 3 meters .
Maybe better than PDK ???
When i have time i go to build the TOTeM. i will make the field test ,see the results,and post here.

Hi Morgan.
From what i saw about the spark test i believe that it is important the distance who detects the battery spark but not nessesary. How importand but not nessesary??? very simple at some lrls needing the spark and at other not. Your opinion???

[Qiaozhi]

The shape of the TOTem is realy like a indian TOTEM,but the important is the field test.
Like the PDK, TOTeM can detect the spark from several meters away, and a TV (with a CRT) from 6 meters. It has both passive and active modes of detection, and can act as a metal detector pinpointer. It also rejects ferrous targets. There is an audio beeper (that can be switched off), LEDs for a visual indication of a target, and a meter to show the signal strength Basically, it's an experimental LRL platform that allows you to test the various modes used by other LRLs. The enclosure is somewhat taller than most LRLs, due to the unique balancing method used for the ferrite coil. This method makes it much easier to achieve a good balance point.

[hung]

Hi Morgan.
From what i saw about the spark test i believe that it is important the distance who detects the battery spark but not nessesary. How importand but not nessesary??? very simple at some lrls needing the spark and at other not. Your opinion???

I have already stated a few times that the distance of detection of a spark is not directly related to the distance of detection of gold when employing ionic/electric field detectors such as the several versions of PDs, Mineoros, etc.

Just because a particular device can detect a battery spark from 30 meters, does not mean that it will detect long time buried gold at 30 meters.
It means that the device detects a battery spark at 30 meters. Just that.

The FG90 detects a battery spark from 35 cm. But a tiny small long time buried gold sample from 3-5 meters. The PDC210 can detect the same 1.5 V battery spark from 1.8m. But cannot detect the same tiny gold sample from 3-5m.
It's a matter of correct frequency and some CRITICAL elements that are featured in the signal and that makes the relevance of the 'DNA' for gold.

This is how we say in Brazil... the 'cat's jump'.

[Geo]

I have already stated a few times that the distance of detection of a spark is not directly related to the distance of detection of gold when employing ionic/electric field detectors such as the several versions of PDs, Mineoros, etc.

Just because a particular device can detect a battery spark from 30 meters, does not mean that it will detect long time buried gold at 30 meters.
It means that the device detects a battery spark at 30 meters. Just that.

The FG90 detects a battery spark from 35 cm. But a tiny small long time buried gold sample from 3-5 meters. The PDC210 can detect the same 1.5 V battery spark from 1.8m. But cannot detect the same tiny gold sample from 3-5m.
It's a matter of correct frequency and some CRITICAL elements that are featured in the signal and that makes the relevance of the 'DNA' for gold.

This is how we say in Brazil... the 'cat's jump'.


Hi Hung.
I believe that you know that we don't locate every time the same """field""". The signal from long time buried objects is not always the same. So some times we need lrl that detects the sparks and other times we need other types lrls.
For example when trying to obtain the energy emitted from the gold when it releases electrons from the outer shell. This was the reason that Esteban says that it is better to construct a double in one detector.

Regards:)

[Geo]

Like the PDK, TOTeM can detect the spark from several meters away, and a TV (with a CRT) from 6 meters. It has both passive and active modes of detection, and can act as a metal detector pinpointer. It also rejects ferrous targets. There is an audio beeper (that can be switched off), LEDs for a visual indication of a target, and a meter to show the signal strength Basically, it's an experimental LRL platform that allows you to test the various modes used by other LRLs. The enclosure is somewhat taller than most LRLs, due to the unique balancing method used for the ferrite coil. This method makes it much easier to achieve a good balance point.

Hi Qiaozhi.
Why you did not use a rotated switch with only one potentiometer and without on-off switches???

Regards

[Qiaozhi]

Hi Qiaozhi.
Why you did not use a rotated switch with only one potentiometer and without on-off switches???

Regards
Because the potentiometers are 10-turn precision types, and these are not available with an on-off switch. But, even if they were, it would be extremely annoying to have to turn the control knob through several rotations to find the threshold every time you switched on the device. With the design as it is, the TOTeM can be switched off, and both the LONG RANGE and SHORT / MEDIUM RANGE thresholds can be left in their current positions.

There is some method in my madness. :cool:

[Qiaozhi]

The prototype TOTeM unit did not have any writing on the control panel, but the book shows the purpose of each control, as shown below:

[Geo]

Thanks Qiaozh.
Also before one hour i opened the book and saw the schematic carefully.
You have right!!!!

Regards:)

btw... who is the owner of the name Totem??? you or Carl??

[Qiaozhi]

Thanks Qiaozh.
Also before one hour i opened the book and saw the schematic carefully.
You have right!!!!

Regards:)

btw... who is the owner of the name Totem??? you or Carl??
Regarding the LRL stuff in the book, Carl wrote most of the LRL chapter (13), but we both contributed to the treasure aura section, and I designed TOTeM (chapter 14). At least no-one can accuse me of commenting on the performance of LRL pistol devices without any firsthand knowledge. :D

As I said, "Here there be dragons".

[Morgan]

Hi Morgan.
From what i saw about the spark test i believe that it is important the distance who detects the battery spark but not nessesary. How importand but not nessesary??? very simple at some lrls needing the spark and at other not. Your opinion???

you right Geo, one example,my PDK-3 cant pick the 1,5V spark,and the best distance for the spark i get with my PDK-2 is 2 meter.

Anyway if the TOTeM pick the spark 3 m away,is a good EMF locator.

[Morgan]

I have already stated a few times that the distance of detection of a spark is not directly related to the distance of detection of gold when employing ionic/electric field detectors such as the several versions of PDs, Mineoros, etc.

Just because a particular device can detect a battery spark from 30 meters, does not mean that it will detect long time buried gold at 30 meters.
It means that the device detects a battery spark at 30 meters. Just that.

The FG90 detects a battery spark from 35 cm. But a tiny small long time buried gold sample from 3-5 meters. The PDC210 can detect the same 1.5 V battery spark from 1.8m. But cannot detect the same tiny gold sample from 3-5m.
It's a matter of correct frequency and some CRITICAL elements that are featured in the signal and that makes the relevance of the 'DNA' for gold.

This is how we say in Brazil... the 'cat's jump'.


yes,right too...

[Morgan]

Regarding the LRL stuff in the book, Carl wrote most of the LRL chapter (13), but we both contributed to the treasure aura section, and I designed TOTeM (chapter 14). At least no-one can accuse me of commenting on the performance of LRL pistol devices without any firsthand knowledge. :D

As I said, "Here there be dragons".

What about TOTeM field test,did someone take it to the field ? What was the results?
Did TOTeM pick some medieval gold dragon ? ;)


Regards

[Qiaozhi]

What about TOTeM field test,did someone take it to the field ? What was the results?
Did TOTeM pick some medieval gold dragon ? ;)


Regards
As I said in the "Conclusions" section: "It easily passes all the laboratory-based tests used by LRL experimenters and certainly appears to react in the same way as the device shown in the internet videos. Whether it will lead you to treasure or not is maybe another story, but at least you will have the opportunity to explore the pseudo-scientific world of long range locators for yourself, and make up your own mind on the matter".

Elsewhere in Chapter 14, I also commented:"Does it work as a metal detector? At least in the active mode at short range, the answer is yes. When used in the medium range mode there are definitely signals being detected, and you even occasionally appear to be following a "signal line". In the passive long range mode the same can be said to be true, and it certainly acts as a very sensitive electromagnetic field detector".

And finally: "The purpose of this project was to develop a 'working' experimental platform for anyone wishing to investigate this grey area of metal detecting. This is a highly speculative area of research, and there is absolutely no guarantee of success. Remember ... here there be dragons!".

Yes, I did test TOTeM in the field, and no I didn't find any gold. :frown:
Perhaps there just wasn't any there to find. ;)

[Geo]

As I said in the "Conclusions" section: "It easily passes all the laboratory-based tests used by LRL experimenters and certainly appears to react in the same way as the device shown in the internet videos. Whether it will lead you to treasure or not is maybe another story, but at least you will have the opportunity to explore the pseudo-scientific world of long range locators for yourself, and make up your own mind on the matter".

Elsewhere in Chapter 14, I also commented:"Does it work as a metal detector? At least in the active mode at short range, the answer is yes. When used in the medium range mode there are definitely signals being detected, and you even occasionally appear to be following a "signal line". In the passive long range mode the same can be said to be true, and it certainly acts as a very sensitive electromagnetic field detector".

And finally: "The purpose of this project was to develop a 'working' experimental platform for anyone wishing to investigate this grey area of metal detecting. This is a highly speculative area of research, and there is absolutely no guarantee of success. Remember ... here there be dragons!".

Yes, I did test TOTeM in the field, and no I didn't find any gold. :frown:
Perhaps there just wasn't any there to find. ;)


Maybe the Dragons took it :lol:

Regards

[Qiaozhi]

Maybe the Dragons took it :lol:

Regards
Yes, maybe you're correct.
Those dastardly dragons are always looking for longtime buried gold. :lol:

[Dedevil]

Carl and I are proud to announce that we have successfully completed the writing of a technical book on metal detector technology.

This is the first in-depth book on this subject since 1927; and it feels like we've been working on it for that long! Countless hours have gone into the production of this book, not only writing, but building and testing the many projects, sometimes multiple times.

Inside the METAL DETECTOR

ISBN 978-0-9858342-0-3
Publication date: September 2012
300 pages

$34.95 - available directly from Geotech.

Here is the Table of Contents to whet your appetite:

Introduction

Chapter 1: History of the Metal Detector
The People
The Applications
The Companies

Chapter 2: The BFO Principle

Chapter 3: Designing a BFO Detector
Reference Oscillator Design
Search Oscillator Design
Mixer and Detector Design
Headphone Amplifier
The Complete BFO Detector
Using Oscillator Harmonics
Construction Details

Chapter 4: A Simple Probe That Works!
Search Oscillator
Automatic Tracking Circuit
Construction Details

Chapter 5: Induction & Coils
Magnetic Fields
Induction
Induction Balance
Eddy Currents
Search Coils
Mineralization Effects

Chapter 6: Principles of Induction Balance
Transmit Frequency
What the Experts Say
So What's Best?
Power Supply
Evaluation of Initial Design Decisions

Chapter 7: Target Discrimination
Phase Demodulation
Motion Versus Non-motion
Discrimination With an Analog Detector

Chapter 8: Transmit-Receive Detector
Transmit Oscillator
RX Amplifier
Audio Output
Power Supply
Testing
Construction Details

Chapter 9: Designing an IB Detector
Aconyms
Stabilized Power Supply
Transmit Oscillator
Receiver Preamp
Designing a VLF IB Detector with GEB
GEB and DISC sampling
CMOS Analog Switches
Motion Mode of Detection
Audio Oscillator, Chopper and Amplifier
A Little More Info On Discrimination
Automatic Battery Check Circuit
Battery Pack
The Completed Prototype
Initial Setup Procedure
Real World Testing
But Can We Do Better?
Improving the Design
Comparator Operation
Detector Calibration
Real World Testing (again)
In Conclusion
Construction Details

Chapter 10: IB Coil Experiments
Experiment #1: MD-3030 10" Concentric Coil
Experiment #2: Fisher M-scope 11" Concentric Coil
Experiment #3: Garrett Crossfire 8" Concentric Coil
Experiment #4: Troy 9" Concentric Coil
Experiment #5: Viking 6DX Double-D Coil
Constructing Homemade IB Coils
Double-D Coil Experiment
Double-O Coil Experiment
Concentric Coil Experiment
Omega Coil Experiment
Conclusion
Step-by-Step Instructions for Constructing a DD Coil

Chapter 11: Pulse Induction Principles
PI Transmit
PI Front End
Sampling
Digging in Deeper

Chapter 12: Pulse Induction Designs
PI Design 1
PI Design 2
PI Design 3
PI Design 4
Bonus: PI Design 5
Advanced Topics
Power Supply
Preamp
Sampling
Ground Balance
Coils
Really Advanced Topics
Construction Details --- PI-1
Construction Details --- PI-2
Construction Details --- PI-3
Construction Details --- PI-4

Chapter 13: Long Range Locators
Dowsing
History
Reactions
Why Dowsing "Works"
Dowsing Tests
Empirical Results
Summary
LRLs
"Passive" LRLs
"Active" LRLs
MFD Theory
Summary
Treasure Auras
Photographing Treasure Auras

Chapter 14: Pistol Detector
Ferrite Receiver
TX Circuit
The Sky and Compass Effects
Detecting the Anomaly
The Front Panel Controls
TR Mode of Operation
Nulling the Ferrite Coil
But Does it Actually Work?
Meaning of TOTeM
Construction Details
Conclusion

Chapter 15: Loose Ends
Multi-frequency Design
Myths & Fallacies
Is it an antenna?
The Halo Effect
Metal or Plastic Stem Bolt?
Electrostatic Shielding
Power Output
Coil Sensitivity
The Concentric Ring Experiment
Component Marking Standard
Electromagnetic Terminology
PC Boards

Appendix A: Air-Cored Coil Calculator
The Visual Basic Version
The Tcl/TK Version
The Javascript version
Accuracy

Appendix B: Resources
Web Sites
Books
Magazine Articles
Patents

Index


If I'm not mentioned then i'm not buying it. It's just another scam detector designed to rob your wallet. :razz:

[Qiaozhi]

If I'm not mentioned then i'm not buying it. It's just another scam detector designed to rob your wallet. :razz:
If you want, we can add you to the list of people (along with Hung) who are banned from having a copy.

We'd hate you to actually learn something, as it would ruin the entertainment value. :lol:

[Dedevil]

If you want, we can add you to the list of people (along with Hung) who are banned from having a copy.

We'd hate you to actually learn something, as it would ruin the entertainment value. :lol:

Thinking you are going to find gold by buying this book is dillusional. End of story!

[J_Player]

If I'm not mentioned then i'm not buying it. It's just another scam detector designed to rob your wallet. :razz:

Thinking you are going to find gold by buying this book is dillusional. End of story!

If you want, we can add you to the list of people (along with Hung) who are banned from having a copy.

We'd hate you to actually learn something, as it would ruin the entertainment value. :lol:Find gold? :???: ... :rolleyes:
Is it a gold-finding LRL book, or is it a technical book about metal detectors?
Some folks will never know, and the forum entertainment will live on! :lol:


Best Wishes, :)
J_P

[Qiaozhi]

Thinking you are going to find gold by buying this book is dillusional. End of story!
Clearly you are incapable of reading the list of contents. :frown:

It is always important to understand the facts first, before posting.
Also read JP's reply, which may give you a hint. ;)

[Dedevil]

Find gold? :???: ... :rolleyes:
Is it a gold-finding LRL book, or is it a technical book about metal detectors?
Some folks will never know, and the forum entertainment will live on! :lol:


Best Wishes, :)
J_P

HA! Busted! Just hacked into CIA and downloaded a free copy. Upon dowsing the pages found the following conclusion; if you take the 3rd letter from the fourth word and then the 2nd letter from the sixth word and then the fifth letter from the eighth word and so on in a mathematical pattern the result is a message from Carl,
It spells,
I hope I retire on this one. Tahiti here I come!
Knew there was a conspiracy behind it all.
rgds

[WM6]

Knew there was a conspiracy behind it all.
rgds

Sure, but your deciphering attempt is completely false.

[Fred]

Hi !
Just discovered the existence of this book, congratulations to the authors ! :)
Probably the first book that technically reviews LRL´s with an open mind and a technical project.

I have plenty of high quality multiturn verniers knobs, just missing everything else for now :rolleyes:





Thanks Geo. I seem to remember Carl telling me that he was able to trigger the Mineoro FG80 with his garage door opener.

Hahaha, that remind me some funny moments here on Geotech...