Tag 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.

1 Teknetics G2 on a deep silver dime

I’m planning to do a series of metal detector demos on this same dime before I dig up my test garden to move to a new house.  It was originally buried about 7 or so years ago.  First up is the Omega G2…  Interestingly, the G2 is designed to be a “gold detector” or in other words, for gold prospecting.  It has found a huge following in the world of relic hunting due to its great depth on low conducting targets (lead, brass and gold)  The G2 operates at 19 kHz (higher frequency typically means more sensitivity to lower conductor metals)

When I first tested the G2, I figured there was no way it would be a good coin shooter due to the frequency.  I was actually quite wrong!  It even hits the deep silver dime, as you’ll see in the video.  Comments and questions are welcome!

20 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.

Continue reading

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….

Continue reading

1 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.

Continue reading

Teknetics G2 Review

Teknetics G2 review

Mark Ellington
www.detectorstuff.com

“In the Spring a young man’s fancy lightly turns to thoughts of love”. For the not-so-young man (me), in the Fall my fancy turns to thoughts of metal detecting.  The Teknetics G2 arrived just in time to tickle my fancy!  (read more…)

Continue reading

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.

Continue reading

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.

Continue reading