Search Results for: dave johnson

3 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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2 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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Fisher F70 Review

fisherf70

“The Heat!”

To put it bluntly, the Fisher F70 is THE HEAT! As a proud and happy owner of an F75, I caught myself thinking…”I bet the F70 will be a scaled down F75”. In some ways, I was right. A few less features than the F75, (and I LOVE the F75 trigger!…it should be illegal to build a metal detector without a trigger!) However, Fisher retained the most useful functions and made them very accessible to the user. There’s also a little something extra under the hood… more depth than the F75! Yep, you read that right! In my soil, coil-for-coil, the F70 is slightly deeper than the F75.

Speaking of coil-for-coil, if you already have an F75 you can swap coils back and forth. The new elliptical concentric coil for the F70 is great! Excellent design, construction and balance. However, slap the big F75 11” DD coil on the F70 and hang on! I’m talking SERIOUS depth here! Select the “slow” option in areas that will allow it (lengthens the sampling time on the target…if I understand it correctly) and you will be getting way, way down in the ground! (I picture moles, grubs and earthworms packing their bags and fleeing the radio waves in utter terror!) However, due to the lengthened response time, the odds of masking due to nearby trash are increased…but I love having the option to pick which way I want to hunt, depending upon site conditions.

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1 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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1 Learn Your Metal Detector – Bill Ladd

Copyright Bill Ladd 2007

Contents not to reproduced without written permission of Bill Ladd


“Learn Your Metal Detector”


By Bill Ladd

One important thing I’ve picked up along the way in this great hobby of ours is to never scoff at, or doubt the unit a fellow detectorist is swinging. This is especially true when a fellow hobbiest is carrying a detector some would consider “cheaper” or “outdated” technology. I’ve seen far too many times these wily old vets do just as well, if not better, than all the competition in the same field that day. Why? Well, as we all know, sometimes it’s just the luck of walking over the right spot. But more so, I believe it’s because the detectorist with the older unit has years of experience with his particular machine than the others. Even though his detector may not be digital, multi-frequency, or full of all the latest “bells and whistles” as some of the more expensive modern units, the user knows it. He or she knows it like the back of their hand; just knows the “sounds”. This hobbiest has trained his ears….it talks to he or she so to speak. Perhaps the other treasure hunters were trying out a new brand of detector that day in hope of attaining some kind of edge. But, new detector users often have to struggle though a tough learning curve of several hours with all of the advanced tones, notching, and digital readouts and programming common on today’s top units. Many of us feel new users need a minimum of 30 hours in the field to really grasp all that a new metal detector is trying to “tell” you. A “newbie” to the hobby may need more than twice that.

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  • March 4, 2009

1 Detector Stuff Interviews Jorge Saad, Fisher Labs Engineer

jantonsaad

DS: Hi Mr. Saad! Thanks for taking the time to answer a few questions about the very unique F5! There is a lot of interest in the metal detecting hobby about this unusual detector… First of all, tell us about yourself…. How long have you been designing metal detectors?

Jorge: Good day Mr. Ellington. It is a pleasure to have the opportunity of speaking with you. I first learned about the metal detector’s technology barely three years ago, when I was hired in First Texas Products and got under the expert lead of Dave Johnson and John Gardiner, who you know are two of the top leading engineers in the Industry. Before that I used to write firmware for other kind of products.

DS: What machines have you had a hand in designing?

Jorge: I was involved in the design of the Bounty Hunter Platinum and Gold; and the Fisher F5 machines.

DS: What’s it like working at First Texas? (The people you work with, the philosophy, atmosphere, etc.)

Jorge: FTP is unique in many aspects. We have a very friendly and open environment. Dave, John and Mark are great people to work around. We are quick with a joke and always on the mood to help each other. Our CEO is also a great guy to work for. We consider ourselves happy to be working here, and that adds a lot to our team. In addition the philosophy of FTP has always been geared towards overall customer experience and satisfaction; as a result here in the Engineering Department we keep open and in touch with as many people using our products as we can spare time for. To learn from their experiences and preferences is vital to develop the metal detectors they dream about – or at the very least get close. As close as physics will allow! We are lucky to enjoy a wonderful support and feedback from our customers and field testers via forum chats, email and phone calls. Those guys are an indispensable part of this team!

Read more of this great interview below!….

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Discrimination Mode "Sensitivity" and "Depth" in Single-Frequency VLF Metal Detectors

*Used with permission of Fisher Labs*

Dave Johnson, Chief Designer @ FTP & Fisher

Some metal detectors are “more sensitive” than others, and “how deep” a particular metal detector can detect a specific metal object depends on many variables.

“Air test sensitivity” refers to the maximum repeatable detection distance achievable in air using a standard metal test piece (typically a US nickel coin), with the searchcoil that’s standard with that model, in a location without electrical interference, the machine adjusted to just barely eliminate background chatter. If ground balancing is available on the machine, it must be done using ferrite. …….. A properly done “air test” provides an indication of a machine’s potential to “go deep” on buried coins. Because of interference from magnetic iron minerals in the ground, actual detection depth will usually be much less than what’s achieved in “air test”. (NOTE: for maximum depth on buried objects, search in the all-metals ground balanced mode, which is much less affected by iron minerals.)

“Sensitivity control” A control labeled “sensitivity”. It actually controls either gain or threshold, or a combination of both, depending on the machine. If both, the higher settings vary threshold and the lower settings vary gain.

“[Audio] threshold control” Determines the signal strength level corresponding to the threshold of audibility. A negative threshold setting is used to suppress signals by a fixed amount so that only signals stronger than that amount will be heard. Negative threshold settings are used to silence internal “circuit noise” and electrical interference. Machines which have no threshold control have an internal threshold which allows silent operation, or a control labeled “sensitivity” which actually controls threshold. …..Some models allow positive threshold settings. In most cases the positive range controls the loudness of a minimum detectable signal, a separate internal threshold determining what will or will not be detected.

“Gain control” This makes signals bigger or smaller. High gain settings make signals bigger, and therefore signals which were originally weaker can more easily exceed the audio threshold, and be heard. If the gain setting is too high, electrical interference or internal circuit noise may cause constant audio chatter. ….Lower gain settings reduce the size of signals, so that relatively weak unwanted signals (electrical interference, deep iron fragments, aluminum foil shreds, etc.) can be silenced.

The effects of discrimination “Discrimination” between different metal objects is done using a different set of signals than the ones used for detection. Since the overall purpose of discrimination is to eliminate response to certain classes of metal objects beginning with metallic iron, magnetic iron minerals in the ground will tend to make nonferrous metal signals look more like ferrous, increasing the probability of their being rejected by the discrimination circuit. Some machines provide data on the amount of iron mineralization, so with experience you can estimate the depth of effective detection and discrimination on that site.

Interactions between controls There are many types of discriminators, all of which have some effect on “air test sensitivity”. The most common pattern (nearly universal in older all-analog machines) is that “air test sensitivity” decreases slightly as discrimination is increased. Most of our recent designs do discrimination entirely in software, where control settings are actually data which don’t necessarily do the same things to signals that circuit components used to do. In the case of the T2 and F75, those differences were confusing to some users. In general if a T2 or F75 seems too noisy, the solution is to set the discrimination level to the iron range; and if that doesn’t do the job, also reduce the sensitivity setting. In the F70 and F5 which are more recent designs, the interactions between control settings and signals are even more complex, but we did a better job of hiding the details thereby giving the user an improved sense of predictability.

Electrical interference In many (probably most) machines, elimination of electrical interference is best achieved by setting the discrimination level to the top of the iron rejection range, then reducing the threshold setting (if threshold control is available; it may be labeled “sensitivity”). Even if the machine chatters in air, while actually in motion searching over the ground it will usually quiet down, except for occasional random pops which don’t sound like targets. (Frequency shifters found on some machines are beyond the scope of this essay.)

How much depth should I get? There is no single answer to that question. In a few places, you may get in-ground depth almost as good as in an air test. There are also a few places with so much iron or salt mineralization that most detectors are not even usable. In most soils, the best discriminators will usually detect coins to a depth of 7 inches or more, and will usually provide usable discrimination and target ID to a depth of 5 inches or more. However, a particular target may not be detected or may be misidentified because of the proximity of rocks or other metal targets, disturbed soil caused by digging, peculiarities of the target, or suboptimal user technique for that target in that setting. On sites where the discriminator doesn’t provide enough depth for your purposes, search in the all-metals ground balanced mode if the machine provides one.

Copyright First Texas Products and Fisher Labs File: sensitivity and depth last update 18 Sept 08