Category Archives for Dave Johnson

Fisher F75 SE on deep silver dime

F75large-popUpeditHi everyone…here is the next in my ongoing series of metal detector tests on the same deep silver dime.  Up to bat is the Fisher F75 SE.  So far, this one knocks it out of the park as “best” at giving me a “DIG ME!” signal on the dime.  Like I’ve said before though, lots of variables to consider from ground moisture to undetectable RF noise.

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.

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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Teknetics Omega Review and 11" DD coil

*I prepared this Omega Review quite a while back, but held it while I field tested the new 11″ DD coil too… so this review will be for both products: The Teknetics Omega and the optional 11″ DD coil.*

Mark Ellington

Detectorstuff.com

OmegafaceAs most of you know, I am a big fan of the Fisher F5! The F5 blew me away with the “control” I had over how I wanted to hunt…and its amazing flexibility to handle various soil and radio noise pollution situations. However, as much as I love the F5 and despite its growing “cult” following, the Engineers at First Texas knew there was even more potential in the basic electronic platform from F5. The always amazing Dave Johnson wanted to create a machine that exceeded the performance of the F5 and simplified the controls. (One thing for which I’m very thankful…. Dave Johnson is NEVER satisfied with status quo!).

When I was given the chance to field test the Teknetics Omega 8000, I jumped all over it! I knew it grew from lessons learned on the F5, so expectations were high. The Omega did not disappoint .

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Fisher F5 Long Review (features breakdown)

I’ve had a lot of questions about the innovative F5 over the past few months.  This is a feature break down I did that was posted on Kellyco’s site.  Hopefully you’ll find it useful

Fisher F5 Field Test

Mark Ellington

Fisher F5 Face

Fisher F5 Face

I was given the wonderful opportunity to do some field testing with Fisher’s amazing new F5. The F5 is one of the most unique detectors I’ve put my hands on in a very long time! The perfect blend of cutting edge, software driven power meshed with the feel of good old fashioned knobs. I find it very interesting that the “oldest name in metal detecting” is utilizing the newest technology! The F5 is the result of Fisher’s self proclaimed “war on bad user interfaces”. The lead Engineer on the F5 was Jorge A. Saad.

Since Fisher Laboratories came under new management, the Company has not been resting on their laurels! First out of the gate came the incredible F75, followed by the mid-range F4. Next up was the affordable F2, then recently the incredibly deep F70. That leads us up to the innovative F5!

The F5 is situated in the familiar F2/F4 housing, but the electronics are entirely different. This platform was designed by Engineers Jorge Saad and Dave Johnson (with John Gardiner and Mark Krieger additionally lending their talents) to offer outstanding discrimination, depth and ID capabilities. You’ll find the F5 mounted on the familiar gold and black “S” rod which has proven its ergonomics and durability throughout the years.

*Click below to see the rest of the review*

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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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Teknetics Delta 4000 Review

Teknetics Delta 4000 Review

Mark Ellington

www.detectorstuff.com

*Review based on prototype version…subject to change!*

(click on images to zoom)


The Teknetics T2 has developed quite a cult-like following since its release! With good reason…It is powerful, lightweight and innovative. It is chock full of useful features that appeal to advanced users in this wonderful hobby.

The Teknetics name has long been synonymous with performance…and that legacy is continued with the launch of the new Teknetics Delta 4000. Lead Engineer on the Delta is John Gardiner. He has had a hand in many recent metal detector releases, including the Fisher F75 and F70. He was backed up by Jorge A. Saad (see my Fisher F5 review for more on him) who wrote the core software code. The legendary Dave Johnson designed the hardware and is overall Lead Engineer for the Teknetics line of metal detectors.

p1030285deltaface

Teknetics Delta 4000 Face

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