Fisher Impulse AQ Discrimination Explanation

[Skull diver]

Being a scuba diver and hunting only underwater for gold, I'm thinking more to another aspect than the discrimination.

Assuming a really clear sand with next to zero mineralization and low GB , how can we manage to use the pulse delay to 7ms in saltwater?

I just hope there will be a serious interference elimination system to avoid to be forced in raising it up to 11.5 if not over... (which is actually what I do to keep stable and quiet my TDI Beachhunter with a DD coil)...

Also, the brake effect of the coil bolts area is another doubt.

 

[Steve Herschbach]

4 hours ago, Joe Beechnut OBN said:

I really don't see myself needing discrimination on the "AQ" at several of the beach's I hunt. I've found that "In the water" the Ocean, or Bay is constantly classifying  the targets. Sand is constantly moving, targets are moving  by weight, size and shape. There are areas where heavier targets have settled but then it's just a matter of knowing the area and watching for the right signs/targets and Sand movement. Then digging all. Going to be a interesting year once we see a few "AQ's" in action, specially here in the states where competition can be intense. Come on "AQ" 

I'm with you Joe, it's about site selection and dig dig dig. I have to be honest I just want a new toy. It needs to have raw power and decent ergonomics, and I'm seeing both here. So a new toy, and better yet something actually new from a company I have been wanting to root for but have not had good reason in some time. It's hard to understand why the old Impulse went away so many years ago and was never replaced, but that's all water under the bridge now. This is still analog and it will be exciting to see where it goes with the leap to digital and the advanced signal processing that is then possible. Many of us believe some audio nuance gets lost with digital signal processing however so I am sure a last go at analog before making that leap will be just fine with a lot of people. Anyway Joe I'm looking forward to comparing AQ notes with you. Thanks for joining the forum.

[okara gold]

I am definitely on board with the AQ. For years I water hunted with the Infinium while living in the Adirondack Mountains of NY. Loads of iron ore and concentrated black sand on many of the beaches. My backup machine was an Excalibur, but head to head comparisons of the two with the black sand issue had me using the Infinium solely. Digging it all was my way of life. Then I jumped on the ATX and with its power I was digging deeper gold rings along with just about everything else. Took it to Arizona and immediately found nuggets in old worked patches. Unfortunately 2 coil wire problems within the first year had me selling it right after the warranty expired. So now I wait on the new AQ and will be digging the extra mile.

[Tony]

13 hours ago, LowTide said:

The next big advancement in PI is going to be AI("I’m sorry Dave, I’m afraid I can’t do that").  And you can tell your grandchildren that you read about it here!

Via Temperature sensors, Accelerometers, and Magnetometers etc the detector will learn about it's environment.  EMI, ground noise etc all handled behind the scene.  And I have a sneaking suspicion that there is code already being tested below the Equator.

Definitely the case...I suspect Minelab already has a range of advanced prototype technology that can be brought to market whenever the need arises. Their R&D budget is...........a lot.

 Tony 

[Steve Herschbach]

2 hours ago, okara gold said:

Unfortunately 2 coil wire problems within the first year had me selling it right after the warranty expired. So now I wait on the new AQ and will be digging the extra mile.

Honestly a real shame Garrett never fully exploited the ATX circuit by hobbling it with a 7 lb box and a crazy coil design. I’ve screamed for years for an ATX that looks like the Impulse. All to the benefit of First Texas however so too bad for the neighbors in Garland. My incredibly crappy cut and paste “prototype” LTX from 2014.....

[okara gold]

Now There's something I'd be interested in!

[Steve Herschbach]

I have tried by writing quite a few different articles in slightly different ways to find the right combination of words to explain this complex subject. In response to some questions about the TDI I have given it yet another try. I will add a link to that thread to the original post here. It's all the same stuff just explained different ways and I am not the absolute know it all expert on all this. I'm just doing the best I can with the subject but frankly have run out of different ways to say the same thing. Hopefully anyone interested will dig into all my posts starting way back with the Garrett Infinium and through it all get a handle on what PI discrimination is all about. In the future any questions I get will probably just get a link back to these existing posts. It's a lot to study but if you forget about VLF discrimination and wishful thinking and just learn what these detectors can and can’t do I think the effort is worth it. I understand why people love VLF detectors but for me this stuff is much more fascinating and I am addicted to PI power. Instead of worrying about what they can't do I learn what they can do and then apply that for best results, including picking the proper locations to get the best results. But for some people, really, a VLF is a better choice. Not everyone is going to want to use a PI.

[Rick K - First Member]

The AQ uses the same basic electronic tools and realities of physics, but the two channels are handled somewhat differently to favor the largest range of gold jewelry while ignoring tiny low conductors and pushing the cut-off point for iron and high conductors high enough to allow detection of even some 24kt gold jewelry while using tone or mute discrimination.

I am not capable of explaining how this is done because even though it has been explained to me, I don’t have the necessary background in electronic and physics to grasp the details. Even if I did, It may be that going into the deep level of detail on this would be dealing with trade secrets.

Bottom line, the various explanations Steve have given all end up with the same caution - namely that whatever discrimination any PI analogue detector can do is way different from a modern VLF GB/ID detector’s discrimination.

[Steve Herschbach]

It’s still going to be a trade off. That is why there is a Reject knob. If the machine simply had an optimum set ferrous/non-ferrous rejection there would be no need for the knob. It will allow you to open up or restrict the ferrous acceptance and that in turn will allow or reject certain classes of good targets. Further, the ground balance is being employed here first and foremost as a discrimination system instead of an actual ground balance control. That is why there will have to be a different detector for gold prospecting... the inability of this model to finely tune for small gold in mineralized ground. That also means the discrimination aspects, if any, of the prospecting version will likely be quite limited. The reverse of that however means the Impulse AQ is trying to work around the lack of a fully adjustable ground balance system for dealing with both salt and ground conditions, necessitating a control like the Volcanic Sand control.

The bottom line is that for some time it has been quietly implied that the Manta/Impulse would operate to full PI depths while simply and easily eliminating ferrous targets... even seeing through ferrous targets. In my opinion reading between the lines on all this the reality is more complex and there are once again going to be the inevitable trades made between sheer performance and discrimination. I have no doubt the AQ is going to fine tune and advance the capability to a new level. My goal is not to take away at all from what is being achieved here. I’m right up there in line wanting a Fisher Impulse AQ. But it is not going to be a simple case of go dig rings at PI depths with no ferrous dug and no good targets missed. Like all things detecting, there is no free lunch.

But maybe I will be proven completely wrong and I would actually welcome that.  Only time will tell. Check back by the end of the year and we will see.