Geotech

Nothing White's had while I was there.

15 minutes ago, Carolina said:

How similar or dis similar is my Tek Point from the F Pulse ?

The TekPoint & F-Pulse are identical except for color.

For your purpose the Gemini has 2 major drawbacks. First, it's a classic TR design (not VLF-ground balancing) so it is more affected by soil mineralization. Second, it runs at 82kHz which is even more sensitive to mineralization. So it may have problems inside a cave. Probably a better choice (if you really want to use a 2-box style) is the TM808 which is a VLF-GB design running at 6.6kHz.

29 minutes ago, PimentoUK said:

Those who have followed Alex's design from the early days will know how he had plans for some 'twin-coil' arrangement, that apparently could largely cancel the ground/salt signal.

Yep, the missing components were for a bipolar version. Alexandre was convinced that this was the best approach but I convinced him to consider an H-bridge drive which is what he is now playing with. There is a way to use a twin-coil drive to cancel salt but I don't think that was his intent. Rather, it naturally cancels EFE and allows you to run a higher pulse rate.

Battery is 76WHrs, so it's 330mA@14.4V or 660mA@7.2V.

Any rumors on pricing?

On 7/22/2022 at 1:48 PM, Jonathan Porter said:

To break into the African market it needs to outperform whatever is performing right now which is the GPZ7000 or it needs to be very cheap and also have some performance, but needs to be more sensitive than the GM1000 VLF.

JP is right. The TDI-SL was specifically designed as a $1000 detector for the African market. Lightweight, cheap, and ran on AA's but fell a bit short in sensitivity. When we pitched it to various people in Africa the only question we ever heard was, "Does it go as deep as Minelab?" It did not, so we then sent a bunch of free detectors to Africa in the hope that some people would find gold and it would kick-start sales. Never happened.

10 minutes ago, abenson said:

Yea TDI repackage would be a waste of time. ATX repackage in a lighter configuration, waterproof, iron disc, rechargeable battery, and wireless headphones for around $2000 would be a winner IMO.

Yeah, I agree, I think the TDI is at the end of the road. I had designed it with some hooks for ground tracking & performance upgrades but the ATX is a better platform.

To Tom's post, one day I would like to see half-sine make it at least to field testing. I think it has a lot of potential.

4 minutes ago, Jonathan Porter said:

The gold detecting market would have to be over 90% Minelab rught now.  I think ML have every rught to think "they're better" based on sales alone.  

Yup, agreed.
 

On 6/29/2022 at 11:46 AM, phrunt said:

This one is pretty interesting, it looks like a GPZ, combined with a CTX 3030, combined with a normal VLF for functionality and coil design, and includes a full colour touch screen.  I like the GPX 4500/5000 arm cuff on a GPZ body.

And a Garrett coil.

This thing sells for $850 on Ali Express, can't imagine there are too many people willing to pay that much for very questionable performance.

I think it began with the Lobo ST. The Cortes, deLeon, Golden, Tejon, Vaquero, Cibola, and Sandshark all have digital audio. Not sure about the Tiger Shark or Silver, never had one. Compadre was likely still all-analog.

2 hours ago, Gwcracker said:

Steve, the processed digital audio signal is not as informative as the analog unprocessed signal. That's where the true value of nuance would really be meaningful.

All the last-generation Tesoro designs had digital audio.

I can't speak to what coils might be available. The only ones mentioned so far are the 8" (stock, I assume) and a 12", both solid disc style. There is nothing to prevent aftermarket coils but they are difficult to make and with a much smaller market share we'll see if anyone jumps in. But right now we need to finish the design and then see if FTP can manufacture it.

No,we will at least build out the remaining 40 or so we have parts for and then decide where to go with it.

1 hour ago, Steve Herschbach said:

I never understood why a beach machine was getting all the attention first, when the nugget + relic market is a larger slice of the pie.

The beach version is what Alexandre had focused on and was ready first. It did not have the small sensitivity of the (e.g.) SDC2300 and we didn't know how tough that would be to solve. Turns out dropping delay from 7us to 3us wasn't as hard as I feared, although it remains to be seen if FTP can manufacture it.

5 hours ago, NV-OR-ID-CAL-AU said:

So glad to hear this detector can compare to the SDC’s performance, hopefully the price and weight will be better too, I’d pay even more if it has some decent discrimination also.

Can you describe the discrimination abilities on this new detector?

It is light and a breeze to swing. No idea on the price, that hasn't been decided yet. I've lobbied for $2k. No discrimination, it happily finds those rotten can flakes.

4 hours ago, phrunt said:

The reason I think tracking or at least a ground grab would be good on this detector is the market it needs to go for.

...

One of the biggest problems I see with QED users especially new to detecting ones or new owners is they get confused how to ground balance it and find it too hard to use and understand, so making it a bit more simple than the QED would probably be worthwhile if it must be completely manual.

In most places I did not find the manual GB to be an issue. But in one locale the ground varied by the meter and I found myself tweaking the GB every few swings. Once I swap the locations of the fine/coarse knobs then it will be fairly easy to use the thumb to tweak the GB control on-the-fly. As I recall, the QED has to be placed in a particular mode to adjust GB which makes it difficult & tedious. Impulse GB works in any mode.

It's strictly manual, no grab. GPX coils might work (I haven't tried it yet) but you won't get the minimum delay of 3us using them.

It's my understanding that the AQ will resume in the next 1-2 months. It will not have the drop-in batteries but will still have the clip-on NiMH pack.

I finally got the green light to take the Impulse/Gold out for a field test, did so a few weeks ago in N. California. No gold but numerous small lead and quite a bit of rotted tin can flakes. Found some rough edges that need polishing but overall it performed very well. Very light & balanced, a pleasure to swing for hours. It does have the tube batteries, per Joe's photo above, and 8" solid coil.

Small gold sensitivity is pretty much tied with the SDC2300, Impulse may go a little deeper on gram+ nuggets. Biggest drawback is the Impulse is currently manual GB only. Question is whether to finish what we have & release, or develop ground tracking for it.

I lived in Greensboro for many years and walked the tracks in the McLeansville area. Quite a bit of the trackside property is wooded so you're not gonna drag a PI mat around very well, and all of it is private land. But the biggest obstacle to finding this treasure is that the story itself is fake. There was no Civil War gold train and there are no pots of gold. The story originated in 1969 in True Treasure magazine which published mostly fabricated treasure stories. People like Jameson repeat those stories for the purpose of selling books.

It's a souvenir shop ring, off one of those carousels that have a couple hundred common names. Next to the keychain carousel and fridge magnet carousel.

3 hours ago, kac said:

How does that coil handle iron infestation compared to a concentric?

No idea, I don't have one.

Please don't tell anyone (we're trying to keep it under wraps) but that spiffy new coil is available on Amazon:

https://www.amazon.com/Fisher-inch-Coil-Triangulated-Bi-Axial/dp/B09SNVRXHC

Apparently only at Amazon, as far as I can tell. Limit 2 per person.

If anyone can purchase, on the open market, the new Fisher MF detector in 2022 I will send them one of my paychecks. Offer good for the first person who can show proof-of-purchase. I'm not sure why we keep aiming for the foot and pulling the trigger but it sure makes for sore feet and a red face.

I still like lead shot for a target standard though it certainly has more variation than I expected. I recently made another batch of test paddles and measured the pieces to find close-to-nominal weights, ferinstance 0.75gr for #9. Lead shot does have a few percent antimony so, no, it's not pure. BTW, lead shot is made by dropping molten lead inside a tall "shot tower." Making tiny solder spheres by hand is durn near impossible. And you'd still have to make a whole bunch and weigh them all to find the perfect size you're looking for, assuming a standard gets established.

Copper wire bits will also work for test targets. Alloy and diameter are nicely consistent but length may not be, especially for very short pieces. As a piece gets longer, orientation can make a difference and orientation effect can differ with mono, concentric, and DD coils.

I also use aluminum foil pieces, 25x25mm squares stacked to various thicknesses, plus 10x10mm and 5x5mm for "tiny" targets. To compare results with someone in, say, New Zealand would require that our household aluminum foil has the same thickness. Not sure that is so.

All-in-all, coming up with a perfect target standard ain't easy. Everything has pros & cons.

4 hours ago, Tahoegold said:

What is the lift off effect?

As you lower a coil to the ground the ground signal produces a stronger & stronger response because it upsets the induction balance of the coil. When you get down to the last inch or so the effect can actually reverse and the RX signal decreases a bit. To make things worse, in some coils it also causes a slight phase shift that messes up the GB. This can produce ground noise. Generally only a problem in bad ground. Concentric coils are the worst because the TX coil and the bucking coil respond differently to ground vs height. DD coils are better, 00 coils even better. Mono coils don't have the problem at all.

Quote

I need something like a broom, a nice even coverage where I feel I'm not missing something unless I overlap all the way to the deepest point of detection. I think that since the sides are not straight as well, there is probably still a curve to the deepest detection area.

You are right, the curvature of the TX coil means that the TX field density (and curvature) changes along the length. Larger deep targets will respond best at the center and you might find that the tiniest targets are only detectable near the ends. Moderate not-too-deep targets will have a more even response. Speaking of brooms, the Tesoro CleanSweep coil is the only DD-style coil I know of that has both a straight overlap and rectangular coils with no curvature. It should produce the most idealistic response you want. Some people hang on to a Tesoro just because of this coil. I have.