Search Results for dave johnson

Dave Johnson – “Time of Day” and electrical interference

FTP Head Engineer Dave Johnson

*Posted with permission of Metal Detector Engineer Dave Johnson*

First Texas Head Engineer Dave Johnson has always done an awesome job “educating” the metal detecting masses.  Thanks again for sharing your knowledge Mr. J.!

Time of day influences the amount and type of electrical interference, not just local sources but also longwave radio communications (mostly military) from thousands of miles away.

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New Gold Prospecting book by Fisher’s Dave Johnson

Fisher and Teknetics Chief Designer Dave Johnson has written an AWESOME book on gold prospecting with a VLF metal detector!  Tons of great information for prospectors and potential prospectors…as well as folks who just want to “learn more” about metal detectors!   Special thanks to Dave Johnson and Mike Scott for allowing me to reprint the book in it’s entirety here on www.detectorstuff.com !

VISIT the brand new Teknetics website HERE!  http://www.tekneticst2.com/

*reprinted with permission of First Texas Products*
www.fisherlab.com

Gold Prospecting
with a
VLF Metal Detector

Dave Johnson, Chief Designer
First Texas Products & Fisher Research Labs

This book explains how to use a VLF induction balance metal detector for gold prospecting. The author has nearly 30 years’ metal detector design engineering experience and has designed machines in every major metal detection technology category.

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Electrical Interference Essay by First Texas Lead Engineer Dave Johnson

Electrical Interference

First Texas Products & Fisher Labs August 2009

Dave Johnson, Chief Designer @ FTP & Fisher

Dave Johnson, Chief Designer @ FTP & Fisher

Because of the high sensitivity of modern metal detectors coupled with the proliferation of sources of electromagnetic interference, you are likely to encounter electrical interference at times during the use of your metal detector. It is important that you recognize electrical interference when present, and take appropriate measures to deal with it. This will prevent you from giving up on a worthwhile site unnecessarily, or from sending in for a repair a machine which is working properly.

Symptoms of electrical interference

Electrical interference can cause a metal detector to “chatter” spontaneously, to lose sensitivity for no apparent reason, or to cause periodic audio “wobble” or slow waves of spontaneous sound. What you’ll hear will depend on what model of metal detector you’re using, what operating mode you’re using it in, how you have the adjustments set, and what the source of the electrical interference is. The most common manifestation is spontaneous chatter.

All metal detectors are susceptible to electrical interference, but they vary in what kinds of electrical interference affect them. In a given environment some metal detectors may be affected by electrical interference whereas others may not.

Two metal detectors of the same model in the same environment may be affected differently, because of minor differences in operating frequency or because the controls have been adjusted differently.

Common sources of electrical interference

Common sources of electrical interference include: overhead electric power lines, underground power lines, other metal detectors, telephone lines carrying electronic data, computer systems, electric fences, old CRT-based televisions, cell phones, thunderstorms, fluorescent lights, metal vapor lamps, military aircraft with electronic warfare countermeasures turned on, electric motors, VLF military communications systems, and automobile ignition systems. It will sometimes be the case at home, in the showroom, or in an urban environment that there are several different sources of electrical interference present simultaneously.

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Fisher Engineer Dave Johnson's talk with El Paso Chapter GPAA

*reprinted by permission of First Texas and Dave Johnson

File: El Paso Chapter GPAA talk 12 Feb 08 Dave Johnson minor update 25 march 09

The History of Metal Detectors, with Emphasis on Gold Prospecting

Dave Johnson, Chief Designer @ FTP & Fisher

Dave Johnson, Chief Designer @ FTP & Fisher

Good evening! My name is Dave Johnson, and I’m the Chief Design Engineer for the world’s largest manufacturer of hobby type metal detectors located right here in El Paso. The brand names we manufacture include Fisher Research Lab, Bounty Hunter, Teknetics, and a number of private labels. I’ve been designing metal detectors for 27 years for several different companies, so there’s half a chance that if you swing a metal detector, I had something to do with it.

My presentation this evening is on the history of metal detectors, with an emphasis on gold machines. I’m not here to sell my company’s products, but it’d be downright discourteous of me to show up and not bring some literature and a Gold Bug 2 to demo. So after the meeting if anyone is interested I’ll be happy to talk with you.

* * * * *

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April 1, 2009

Information on the new Teknetics Omega- Engineer Dave Johnson

Dave Johnson

Dave Johnson

*Reprinted by permission of First Texas*

Posted originally on American Relic Hunters Official Teknetics Forum

Hello! and, Omega

Posted By: dave johnson
Date: Friday, 13 February 2009, at 1:10 p.m.

Hello, this is my first forum post on this website. Some of y’all I recognize from other venues.

Since the Teknetics Omega is in the process of being released to production, there will be a lot of curiosity about it. Most of the questions will relate to features and performance in the field. There’s no need for me to go into those matters, since other people will quickly fill in the details. What follows here is a bit of information which is probably better coming direct from engineering department.

Once the Omega gets into people’s hands, it’ll become obvious that there is some sort of relationship between the Tek Omega, and several earlier Fisher and Bounty Hunter products. Here’s what that relationship is.

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Detector Stuff Interviews FT-Fisher Engineers, David Johnson and John Gardiner

From left to right: Mark Krieger, New Product Development Engineer; John Gardiner, Electronics Engineer; David Johnson (kneeling), Chief Engineer; Jorge Anton Saad, Electronics Engineer

Introduction:

First of all, I want to thank Tom Walsh, Mike Scott, Tricia Richardson, Dave Johnson and John Gardiner for their help in arranging this interview. I think it’s a fair statement that First Texas – Fisher is one of the most exciting metal detector companies on the planet right now, and as such, has piqued the interest of the hobby detecting world in a way that hasn’t been seen for quite a while.

I had the idea for this interview months ago, before I had started this web site. There was quite a buzz in the forums when rumors started of a new Dave Johnson design coming from First Texas under the Teknetics moniker. After the subsequent release and success of the T-2, the hobby community was set on fire with excitement over the prospects of “things to come”. Another wave of excitement hit when it was learned First Texas had acquired Fisher, and that wave turned into a tsunami with the release of the F-75. Mr. Johnson was quick to point out that the T-2 and F-75 were team efforts, not solo projects, and that Engineer John Gardiner was key to the success of both machines.

The purpose of this interview is to give the fans of metal detecting a “behind the scenes” glimpse of the engineers who designed the T-2, F-75 and F-4. There is an unusual “connection” people in this hobby have with their metal detectors. Over time, they seem to take on a personality of their own, becoming an extension of the owner/user. Because of this “personal” connection, most view the responsible engineers with a sense of awe and mystery. I feel that “getting to know” the Engineers will help people appreciate and applaud the outstanding efforts of these geniuses behind the scenes.

All questions below are for both Mr. Johnson and Mr. Gardiner, unless otherwise designated.

Question 1:

DS: What got you interested in engineering metal detectors?

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Fisher CZ3D on a deep silver dime

Fisher CZ3D

So, my current mission to test all the metal detectors in my stable against a deep silver dime in my test garden continues.  Now…remember…variables is a key word here.  Meaning, time constraints won’t let me test all of the machines on the same day…and I have witnessed numerous times that the exact same metal detector can NOT get the dime one day and then (with identical settings) can get it the next.  The variables I’m talking about are ground moisture, “invisible” RF interference, etc….heck, it could even be moon phases, gov’t conspiracies and UFO’s for all I know.

So, this take this test for what it is…different detectors on the same targets but on different days.  Up to bat today is the venerable Fisher CZ3D.  The original CZ design is dual frequency and originally the brain child of Dave Johnson.  It has had many iterations since with the last being the 3D.  This is a design that goes back to the late 80’s/early 90’s!  Amazing that it still holds it own against the modern crop of metal detectors.

Teknetics Eurotek Pro Review

Teknetics Eurotek Pro Review
2014
Mark Ellington
www.detectorstuff.com

Intro –

OLYMPUS DIGITAL CAMERAYou know, the Eurotek Pro kind of frustrates me! No, no…not because it has any problems . …but, instead , because it performs so blasted well while being so inexpensive ! I mean, I have quite a few much higher priced detectors that can’t do what this little fella does. Sure, it doesn’t have a lot of the features found on high-enders like backlight, notches, etc. But what it does bring to the table is the best performance I’ve found in ferreting out non-ferrous targets that are surrounded by iron.

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A look back at Detector Stuff Metal Detecting interviews

avatar_42014 is here and the start of a new year can be a time to reminisce. As I’m building up some new content, I thought it may be good to also remind folks of some of the great stuff we’ve had here over the years.  I’ve been fascinated with the people behind the scenes that make our hobby fun by creating new and amazing metal detecting equipment!  Below are links to some of our past interviews with industry leaders….

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