By Gerry in Idaho
I thought I was pretty damn good, but this technology has me beat.
Might be time to invest?
Metal detectors often seem to have a 'Depth Gauge'. How is it calculated? Is it the strength (or inverse of it) of the amplitude of the return signal? So, for instance, everything else being equal, the 'deep' target would mean either a stronger target at greater depth or a weaker shallow target?
While we're all abuzz with the announcement and advertised feature and performance characteristics of the XP Deus II, I'm wondering about tests that distinguish between detectors' target separation abilities. 'Word on the street' is that in trashy iron sites, the original Deus is still the best available. Presumably those reports are based upon in-field testing, which of course is the real proof. But the downside is, (AFAIK) these are qualitative observations, not quantitative. Subjectivity involved? Unfortunately, yes.
We do have Monte's Nail Board Test for a special case -- iron nails near a single coin, all in the same plane and typically all on the surface of the ground. Add depth combined with some mineralization (burying the MNB) and you've included another real world dimension. But in the field, multiple nearby targets are seldom in the same plane.
So you hopefully see the purpose of this post. Has anyone seen/tried other methods to better simulate actual in-field conditions to differentiate between competing detectors to best be able to handle trashy sites?
By Rick N. MI
I mostly hunt in lakes and the bottoms are mostly all sand. A test on a sandy beach with the Equinox 800 and Xp Orx, both hit hard on a 14k 3.7 gram gold ring buried at 14". For mild ground I don't see a need for multi frequency. I do like the multiple frequencies on the Orx.
Is there an advantage to multi frequency in mild ground?
By Steve Herschbach
We have the Deus 2 just announced, Nokta/Makro Multi on the way, possibly the next generation Equinox from Minelab, and maybe even another Garrett multifrequency model to follow Apex, all coming in 2022. I guess we should even toss First Texas in there, as they just officially discontinued the CZ-3D, with the possibility something new will replace it soon. If this does not mean we are moving past single frequency, I don’t know what does. Or are we? There will no doubt always be a place for a finely tuned single frequency detector. However, if you consider Deus as selectable frequency, and Equinox as selectable/multi, then very many of us have already moved past a simple single frequency detector as our primary detectors.
This is the thread to speculate on what is coming, where we are, and where we are headed. 2022 is shaping up as the year SMF (simultaneous multifrequency) finally takes off for real. In some detectors, it’s just companies chasing the latest marketing catchword. Multifrequency is only as good as the way it is implemented, otherwise we’d all have been swinging White’s DFX ages ago. It’s not enough to make a SMF detector, it also has to have genuine performance advantages. About the only given is that any multifrequency machine will outperform a single frequency on a saltwater beach. The rest, however, is very much up in the air.
For some detailed explanation of the technology, and a history of past selectable and simultaneous multifrequency detectors, see my write up on Selectable Frequency And Multiple Frequency
Where it all started, Fisher CZ-6 and Minelab Sovereign, both released in 1991. I think Fisher wins claim to being first, since Minelab takes a swipe at them in their Sovereign introduction. Notice how the misdirection on transmitted versus received and processed started on day one.
Fisher CZ-6 Quicksilver. The technology: Dual frequency Fourier Domain Signal Analysis. Patented state-of-the-art analog/digital electronics transmit two VLF signals (one 5 kHz, one at 15 kHz) deep into mineralized soil. The receiver circuitry had two ground compensated target signals to analyze, compare and identify. The result? Deeper targets, more accurate target identification. Wet sand is no problem for the CZ-6, it compensates for salt and ground mineralization simultaneously! Source Fisher CZ-6 Datasheet
"The Sovereign" is the first of the latest generation of metal detectors from Minelab featuring Minelab's new technology called Broad Band Spectrum or BBS for short. This revolutionary new technology which is unique to Minelab has already been awarded patents in the USA, Canada and Australia and has several pending. Unlike other metal detectors which operate at just one frequency, or even the "newest" two frequency machines, "The Sovereign" actually transmits over a wide spectrum of frequencies. The resulting signal that is received from a target buried in the ground is processed by a microprocessor that removes interference caused by ground mineralization which limits the depth at which targets can be found, and often results in inaccurate target identification. The remaining signal can then be analysed to determine the actual composition of targets even if they are deeply buried, or if the ground is mineralized or salt water is present. Thus it is the only detector that can simultaneously reject both salt and mineralization while at the same time accurately discriminating the target, making it ideal for black sand beaches and many desert areas. In many areas that are highly mineralized and have been heavily searched in the past, "The Sovereign" will prove that many of the valuable targets are still there waiting for a Treasure Hunter with the proper detector to locate them. Source Minelab Sovereign Instruction Manual
I love coinshooting, and I'm often in my local parks or private permissions searching for clad and silver coins. But I noticed that when digging up shallow clad coins (3 inches or less), my AT Max with the stock coil would say the coin is 6 inches down. Sometimes, a surface coin would read at being 4 inches deep. I didn't think this was that big of a deal, b/c I could always pull out my F-Pulse and see if the assumed coin target was truly shallow or not. Also, the incorrect depth reading wasn't keeping me from digging a desired target.
Tonight, I read:
Both of these mentioned anomolies or issues with DD coils and shallow targets. Is what I'm experiencing with my shallow coins and AT Max one of these anomolies? Or is there something else going on?