Archive for the ‘Tech Talk’ Category
*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.
When Garrett metal detectors released released the “Ace” series of detectors, they set a new standard in affordable performance. Garrett has been in the business a long time and recognized a “niche” that needed to be filled…and fill it they did! Now, there’s a new release in the Ace lineup…the Ace 350.
The White’s Spectra V3i upgrade…Get it!
I was privileged to receive one of the early White’s Electronics “Vision” uber-detectors last year. Without a doubt, the most user configurable metal detector on the planet! Initially, all the settings and options can seem a little overwhelming. However…if you take the time to really learn this machine, you will be rewarded. The Vision/Spectra V3i CANNOT be mastered in a week or even a month. This is a detector that GROWS with you as a hobbyist. If you purchase one, be prepared to dedicate some serious time studying various forum posts and experimenting…but, boy, is it worth it!
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*
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.
I just got my hands on a sales flyer for a new Gold Bug gold hunting metal detector from Fisher Labs. Very, very interesting set of specs.! One thing that definitely has my attention… 19 kHz frequency and the mention of relic hunting possibilities! (think lead and brass!)…also check out the last item under “Controls and Features”…an optional 11″ DD coil! Could this be an awesome nugget buster and a monster relic machine? Can’t wait to start hearing field reports! Discuss in our FORUMS HERE
First Texas Products & Fisher Labs August 2009
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.
I know this isn’t a metal detector…BUT it is COOL!
It is also the creation of Night Owl Optics, a sister company of Fisher and Teknetics, who are metal detector manufacturers…the metal detector manufacturer connection, and the sheer coolness of night vision is more than enough reason for me to write up a review on the iGen 20/20!
Who hasn’t dreamed of being able to see in the dark? It ranks right up there with breathing underwater and flying with a jetpack! The incredibly cool iGen 20/20 does indeed let you peer clearly into the darkness…not only that, but you can take photos of your nocturnal adventures as well!
Most of my readers may not realize I spent nearly 20 years in law enforcement prior to my current career. Being the resident PC nerd and gadget junkie, I was always involved in new technology grants and purchases. Years ago, I spent time learning how to operate a “Generation 1″ night vision scope. The thing felt like it weighed 30 pounds and had a big, bright green, CRT (Cathode Ray Tube) that you had to peer into. Battery life was abysmal and I spent hours doing “double takes” trying to figure out if you could really see anything with it that you couldn’t see without it! Man, oh man…has technology improved! Let’s check out the iGen 20/20!
This time I take apart the Display/control pod! In the first part of this series, I “deconstructed” the under-arm housing. LINK HERE. Upon removing the screws on the control pod, I am very impressed by the use of a nice heavy rubber bushing/seal. So far, all parts appear to be very high quality on the Spectra V3. Each half of the display seat into a recessed groove…nice and water tight! There’s also a beefy rubber grommet/seal where the pod back connects to the back of the handle…once again helping keep the elements at bay….
READ MORE BELOW! More Pics…
Here are a few views of the interior of the new White’s Vision /V3 (there’s some kinda name issue with Vision from what I’ve picked up…so it may be known as the Spectra V3 in the future) All the components and solders look very high quality! For your viewing pleasure…. (yes…I imagine this would void your warranty!) Full review of the Spectra V3 coming soon!
Fisher was kind enough to send it our way for distribution…if our servers can take the downloads! By the way, overlook the mediocre writer in there named “mark”
*Update* WTN is now posted for download on Fisher Labs Website…get it HERE!