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Some Thoughts On The Fisher Impulse AQ


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The latest developments of the AQ pre-production platform continue to increase the utility of the ferrous discrimination capability of the machine. Steady refinement of the design have made the machine not only deeper overall but greatly narrowed the gap between sensitivity in all metal and sensitivity in the iron ID modes of mute and multi-tone. 

2020 Edit: The Impulse AQ has been revealed - see details here

I suspect that if no iron/steel trash existed at the beach, no serious beach hunter would use anything except a Pulse Induction machine - unless they were in dry sand, and maybe not then. The reason I say this is that the depth advantages of existing PI machines is well demonstrated since they can operate on most beaches without the penalty of using ground balance. Also, except for iron/steel, no other level of discrimination is useful since gold jewelry can appear almost anywhere in the ID range above iron. So of the iron wasn’t there - PI’s would likely dominate. 

In the case of Phase shift discrimination systems like VLF IB detectors use, the strong iron signal dominates the audio output, either silencing the audio entirely in the case of a single tone VLF, by nulling like an FBS/BBS - or by giving a lower tone in a multi-tone Detector. Even in the case of the multitone VLF’s, hearing the non-ferrous target depends on the recovery speed of the processing hardware in the detector. 

With the AQ’s PI time-based discrimination, The discrimination of iron is reported to the user either as silence (in the mute mode) or as a low tone (in the case of multi-tone). 

In mute, not only do you not hear the iron, but you hear instead silence - unless there is a non-ferrous target, in that case you hear the target with no hint of the iron at all. In this mode, the AQ software simply makes the ferrous targets disappear - just disappear. 

In the case of multitone, you hear a high tone for non-ferrous low and medium conductors and a high tone for ferrous targets - close or even superimposed, makes n difference you would hear both tones in any case. 

This has several major advantages. 

First, there is “zero recovery speed” - All targets produce an output signal if they return one - the ferrous is - by operator choice - either silenced or assigned a low tone. The low/medium conductors always return their characteristic high tone. This occurs 100% of the time - there is no “switching delay” from target to target based on processor speed limitations happening. 

Separation distance between adjacent ferrous and non ferrous targets is ZERO. 

By zero, I mean exactly that, even non-ferrous directly beneath ferrous gives a clear non-ferrous high tone and the iron simply “isn’t there” (in mute - in multi-tone it gives a low tone which you would hear along with the non ferrous high tone). 

This means that “silent masking” that Tom wrote about long ago, where even a tiny bit if ferrous like a common staple can mask a deeper and larger valuable target, is largely eliminated. 

Now this isn’t magic, it’s just that the iron is above the ground balance point (or at it) and you are hearing the signals below the GB point and the ones at or above the GB point are silenced (or give a low tone). 

Is it perfect? - no. In discrim on the AQ some high conductor targets will be “above the GB point” and be treated as iron. If your idea of a good beach hunt is finding a bunch of dimes and quarters in dry sand, then stick with whatever light, cheap VLF you want, they can help you avoid all that aluminum and gold which would just slow you down - lol 

All this is clearly demonstrated in the video I have linked to before. The machine in the video is the Manta prototype from 3-5 years ago. The system has gone through a lot of development since then, including the very latest gains in overall depth and depth in the iron ID modes which I reported in the first sentence in this post. 

Will the AQ “obsolete” any other detectors? Depends on what you mean by obsolete. The gas turbine aircraft engine (the jet) quickly replaced the extremely complex, high maintenance multi cylinder reciprocating aircraft engines for heavy, fast and high aircraft, but lots of light aircraft are still piston powered. The piston engine is still undergoing development for some aircraft applications. 

So I expect that IF the AQ in the hands of the early buyers lives up to its claimed capabilities, that serious beach gold hunters will adopt it quickly. When a new tool in the hands of early adopters proves to be superior at doing a specific job to the previous best tools for the job in question, those who are really serious about performance for economic or other reasons will adopt the new tool and stop using the old one. How many framing carpenters still use a hammer. Not many if the compressor/nail gun noise at any construction site is any guide. The framing hammer is not obsolete - it still works just fine - but for serious users the nail gun became “compelling”. 

Time will tell how “compelling” the AQ will become for serious beach jewelry hunters.

 

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Rick, do you also agree the White's TDI has the capability to also see a gold ring covered by nails? 

Being an avid TDI user I know it can also sound off on a gold ring below a pile of iron nails.  In fact, the nicest gold ring I've found was using the TDI in a nail infested area.

If I'm reading the AQ features correctly it will offer a faster target analysis (pulse delay) over the TDI.  Which will mean depth capabilities are greater over the TDI.  Maybe faster recovery between adjacent targets.  I think its already been stated it will be deeper than any VLF machine in the wet salt area. 

What other features that will excel all others?

Why would a person want to buy the AQ?

In hopes of finding gold on a beach where others have hunted and have missed because of excessive depth?
 

 

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I suspect that few have used a TDI in running salt water - why would they, it’s not dunkable.  I did once and when I dropped it, luckily it was on wet sand, not in the drink! Even though no water got in, it wouldn’t work.  I opened it up and there was a loose wire - but loose from where??? I took a picture with my phone and sent the pic to Reg Sniff who I was in touch with through the whole TDI introduction period - he showed me which place to solder it back - lol

Those who did use it at the beach quickly learned that it would run fine with GB off, but that they had no discrimination and with GB on, the depth took a huge hit.  Not just depth on deep stuff, but signal strength on all targets - big stuff deep but smaller stuff at lesser depths.

Your TDI and mine with the GB on and the audio set to report low conductors only would hit the ring under the nails - and with the GB off - hit the nails with or without the ring - forcing us to “dig it all”.  Result, GB off - dig junk.

Result GB on - big depth loss.  This is what doomed the TDI.  It could do cool stuff, but only when the GB was on and the depth was crippled. Killed it in the goldfields (especially Australia) and killed it at the beach.

The AQ is said (I said “said”) to be deeper in all modes, including ferrous ID - than the TDI in any mode, including with TDI GB off - Also dunkable which all TDi’s except the TDI Beachnunter aren’t.

The shorter pulse delay is not about adjacent target discrimination. PI detectors work by sampling the target return at some few microseconds after pulse cut off.  The return signals from targets decay rapidly, the less massive and conductive targets  and those with the weakest signals decaying faster. The sooner you can sample, the more information is there - more sensitive to targets. So deeper is not only about absolute depth, but relative depth. More depth on every target.

I’m pretty sure when production AQ hardware is tested and reported on that the difference will not only be clear, but startling.

If I’m wrong, so be it - you can all come back - I’ll still be here - and tell me what a fool I was. 

If I’m right, I might have to become a dealer!!!

When this reaches the market there will be professionally produced videos which clearly - in verifiable ways - demonstrate its capabilities.

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I've never been in the water with my TDI, coil wet yes but never deeper than 2-3".  I enclose mine in a 3 gallon zip lock bag and only hunt the areas where the water has been.  GB off and I dig it all.  On occasion I'll dig some iron but not as often as most think.  The reasoning behind my statement "Maybe faster recovery between adjacent targets." because in reality, since the sampling is quicker compared to, lets say 10-15, it will naturally have the capability to respond to more targets in a given sweep.  It will be very interesting to see how this develops.  But I can't image it will take over the market if the price is hovering around 2 grand.  Now on the other hand, if there is a land version released with a good discriminator (I mean, discriminate nails and still hit on the high conductors) that would surly be a game changer, if not to pricey.

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Rick, I want to thank you for your post on the AQ.  Last night I had time to actually ponder and absorb what you had to say about the AQ and the relationship between depth and discrimination.  Then I compared your statements to my TDI and its depth/discrimination relationship and suddenly a light bulb came on.  I've been picking and prodding other people that I know are involved with the AQ wanting just a little information and I only get silence.  Well not exactly silence but they all would tell me that this machine would be a huge leap in PI technology performance.  Yea, being a former tester I understand they can't say much, if any.  I always made it a practice to be silent, even my hunting buddies didn't know what I was up to. 

Well enough of all the chit chat, to the point I go.  If the AQ can deliver the same depth/discrimination as the claims, then it will be a huge leap.  Still thinking out loud, if it can obtain a depth of 17" on a ring in the wet salt sand and also have the capability of discriminating out a nail or giving a different audio for the nail that would turn the tide (beach PI competition)  My TDI, with GB off might only detect a ring in the wet sand at maybe 12" but would also give the same audio on a nail at that depth.  On the other hand with GB on, my TDI would struggle to detect the same gold ring at 8" and that is a big maybe. 

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Mark, your TDI experience matches with mine with two different ones.  The last one had Reg’s mods and GB off would hit a nickel at 17” with a 14” mono made by the guy who sold out to Miner John.

The depths are for real, with the latest tweaks to the software, they are getting significant additional depth in AM and in the mute/multi-tone iron ID modes. The ID really works.  The video I posted on the other thread shows that it is for real, but I have seen non-public videos which clearly show how about 4” of pure iron filings simply disappears without blocking detection of a gold ring beneath it. Amazing.

I have posted this several places, perhaps even here Mark, but for your convenience - here is a depth test video from 5 years ago - a lot has happened since then - all of it good. The Manta hits the large ring at almost 20” (50 cm) - the others including a GPX5000 and a TDI manage around 16” (40 CM). It’s in French, but there is a summary caption at the end of each test.

 

 

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Can I assume your TDI is the TDI Pro with mods?

My machine was bought 4 years ago and it is the TDI SL.  Not sure if there are mods for mine that would give a performance boost as mention on yours. 

Thinking a true mono coil would give me extra depth in my area I purchased one form another member of a different forum.  When it arrived I felt something was wrong, I contacted Carl and after his instruction on testing for mono coils it was obvious the coil was in reality a dual field and not a mono. 

A couple years back I remember reading about a mono coil similar to the one you described on your post.  But never did know where they came from.  All that being said the AQ seems to be on track to be a beach game changer. 

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My first TDI was one of the original batch of thru-hole models. It has a pretty warbely threshold about as bas as my SDC2300. The next one had mods devised by Reg Sniff including at least one IC changed.  It had a nice smooth threshold and was noticeably deeper at least in air tests. The coil I mentioned was an open loop 14” mono.  It air tested quite deep but Paul in CA who I sold the whole outfit to believes it is defective.

Folks are justifiably sceptical about the Manta.  It’s disclosed that it will be expensive and there has been so much disappointment in the past about discriminating PI’s that experienced users are wary of any such claims. All I can say is wait and see. Based on my limited time with the proto last October, it does what they say it does.  The ferrous ID could be occasionally fooled by a fresh bottle cap or a very rusty Bobby pin, bit was otherwise very effective on very trashy beaches in Mission Bay San Diego.

They have been working on the discrimination and LE.JAG has posted that it is significantly improved.

Alexandre is a bit of a “mad scientist” type - he is absolutely obsessed with detector design.  It has been his passion for over a decade and I have the strong impression that it’s about all he thinks about. 

Like everyone else interested in this Project, I am unhappy with the time it has taken to get it into production.  There are lots of good reasons for this, having to do with issues like complex 3 layer circuit boards, very special construction requirements for 7 microsecond coils, thorough  testing of the mechanical components and designing and qualifying the assembly and test stations and qualifying the operators. 

Meanwhile, back in the “Doc Brown’s Secret Laboratory” (I mean Alexandre’s place in France) - “Doc Brown” (I mean Alexandre) is busy with his “flux capacitor time machine” (I mean the AQ and a series of follow on model detectors) - after all, isn’t that what metal detectors are - time machines?? Lol

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