Pulse Induction Training - Wet-Salt

Pulse delay is the period between the rapid shut-off of the transmit pulse and the reciever’s taking the first sample of the return signal. The BS/BBS/Nox are all continuiosly transmitting and the timings relate to the transmitted frequency shifts (If any) and the length of these periods = ML doesn’t want us to really understand any of this - all the explanations seem to be written by the marketing department vs. the engineering department.

Rick Kempf
Gold Canyon AZ- where there is no gold

So..... Tom is it just possible its engineering....... if we have such variance? We get what the engineer wants the machine to do do we not?

I kind of agree....... there are some machines that just allow the use wayyyyyyy to many buttons to push that other machines are programed to do. That often more times than not leads to the user THINKING hes got the right combination because SOMEONE ELSE is using the setting that may be a 1000 miles away. For beach hunting wet sand and in the was ..... i like the good old KISS method.

Dew...…… As humans...… we are defined by our CAPABILITIES and our LIMITATIONS. Design Engineers...…. or otherwise. An engineer would not willingly design a platform under the premise that it may suffer from market-defeat. Yes...….. we are limited to the single engineers individual capabilities/limitations...…… OR...……. collectively..... the brain-storm/group-thought of a collaborative team-effort.,.,.,., should the product be designed by a 'team'.
NOW...……. social media has (especially as of lately) been a large 'steering-committee' for astute Design Engineers. It's an 'eye-opener' to the DE...…. as well as the consumer.

Carl is K.I.S.S. theory. Worry not.

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* Also...………… When Pulse Delay is minimized...,,,,...…,,,,,,,,,, there's a "physics self-defeat"...… in that...…. the detector will become more sensitive to smaller (and lower conductor) targets....at the cost of losing performance on medium and larger targets.,.,.,.,.,.,.,., such as a man's simple wedding band..... to signet/class rings.

* I just thought of something: In my Beach Hunting DVD...…. I'm using a Fisher CZ (((in Salt Mode))) in the Auto-Tune (All-Metal) Mode. Audibly; this presents extremely similar audio responses to what a Pulse Induction unit will respond/sound like ….. on a wet-salt beach....,,,,, or otherwise. For those that have this DVD...….. this should give you your answer and direction.



Edited 1 time(s). Last edit at 08/13/2018 12:48AM by NASA-Tom.

NASA-Tom --

This is a MOST fascinating, and informative thread. I haven't posted, but I sure am reading with interest, and gaining "education." Priceless!

Steve

I believe we are also limited by marketing....... it seems some want an out of the box machine that is usable by anyone. There is a fear if its not turn on and go it wont sell no matter how good it is...... and i guess that is the bottom line. More so in multi use detectors. So sometimes the DE teams vision ends up ....... shall we say on the cutting room floor? With a PI..... where there is a limited number in the big picture using them currently compared to multi use VLFs..... a break thru could really change beach hunting and sell a lot of machines. Hopefully a design that skirts the limits.... which in the long run will encourage improvements for the next generation rather than business as usual.

With deliberate tuitional intent...… you will notice that I am redundant...… with some of the data being replicated/duplicated in multiple posts.

NASA Tom...... are all PIs created equal? In other words just because a unit can run smoothly at 7 uS is it more sensitive to small gold over one thats a bit chatty at 10 uS. I may well be talking Manta vs TDI here. You mentioned loosing coin and larger gold as a trade off.. ... if a machine is getting 10" deeper than our current VLFs then surely we arent talking about using 7 uS..... it has to be a higher uS? What kind of sensitivity/depth would one loose on the larger gold using 7 uS...... half? Im willing to loose some depth on those larger class rings for some of the smaller gold...... IF the machine will get the smaller gold. Guessing sink rate here in Fl with the hard pan..... im betting i could still double my gold bring home rate and not dig as much as those going after the big stuff at 10" deeper. Let be honest...... a blind squirrel if he goes over a recent drop is getting that. Yes im still whinning for some SMALL gold at that 7 uS..... not tiny. Also..... a lot of machine mass produced arent always tuned exact. I remember a discussion with Bill Craptree when i was going to buy a PI.... he recommended an older one ..... but either way to send it to him to be properly tuned. He said just because it says its a certain uS isnt always so. Id never know if it was 7 uS or 10 now would I? Well....... except by targets being found maybe. Then of course ..... i may not be able to even run 7uS.... thats going to very.



Edited 1 time(s). Last edit at 08/11/2018 11:22AM by dewcon4414.

VERY valid question(s)…. Dew. Here's one of your primary concerns. About 20 years ago...… I had a pair of AquaStar's. Serial #17 & #18. One was substantially deeper on Nickels (men's gold rings)…… while the other AquaStar was more sensitive to smaller gold. This is where I had a double-epiphany. First...………. I nearly refused to hunt with the more 'sensitive-to-small-gold' unit; but/rather, nearly always hunted with the so-called 'deeper' unit. I concentrated/blamed everything on 'depth'. There was "just enough" proof to keep this theory valid...… in my results. Depth is critical.
After a while...… I would 'occasionally' use the other unit that was more sensitive to smaller gold. Suddenly...… the first epiphany took place. Every time I would hunt with the AquaStar that was more sensitive to smaller gold...…. I would ALWAYS come home from the wet-salt beach with gold. Usually NOT ring(s). I realized...…. I (consistently/repeatedly) did NOT come home with gold …..every time I hunted with the deeper unit. Hmmmmmmm. I had witnessed a pattern that was very difficult for me to accept. ((( I was in denial. ))) Soooooooo………… Epiphany #2 took place ….. causing me to send the 'sensitive-to-small-gold' unit back to Bill Crabtree (Mr. Bill) for even more hyper-tuning to tiny gold. This is when the world opened up (unsuspectingly) to something that no one knew about. ((( And now I have a AquaStar that Carl has tuned to 5uS Pulse Delay ))).
Summational Conclusion = It is CRITICAL to have a unit that goes excessively DEEP. It is CRITICAL to have the same unit extremely SENSITIVE to small and tiny gold.

You may have 2 PI metal detectors from the same manufacturer. They both are tuned to go (as low as) 7uS. BUT...… they may not perform the same in the real world!

Yes..... you may also have one PI unit from one Mfr that can ascertain 7uS Pulse Delay. And you may have another PI unit from another Mfr that can only go to 10uS Pulse Delay. Yet...… in the real world...… they may both perform about the same...….. or even...… one may out-perform the other...… and NOT in the order of your expectations. There's a lot of different factors at play. One may not handle flyback very well. One may have proper Pulse Delay; yet, incorrect Pulse Width...… Xmit or Rcv. One unit may utilize saw-tooth waveform...….. and the other truncated half-sine. One may produce a very short Xmit pulse...… and the other Xmits for a longer duration. The variables are nearly infinite.

There is no 'in concrete' standard answer to how much depth is lost whilst running lower/smaller Pulse Delay's. Maybe a paradigm shift has taken place (with multi-period-receive/sensing) whereby; this is now a thing of the past.

Unless you have a O-Scope …… you will never know 'what' Pulse Delay your unit is running on. BUT...………. there are MANY factors that dictate overall performance; and not just restricted to Pulse Delay.

A more valid concern is: Let's say you have a 5uS delay unit that is 'proper'. . . . . . . and can handle the wet-salt. Well...……… 5uS may be TOO LATE! Plenty of gold has already stopped transmitting (radiating/decaying) well before 5uS!!! Ouch!!!!!! Hmmmmmmmmmmmmmmm.


(((Most gold jewelry is Diamagnetic..... and does not "light-up/Xmit" after the source is removed..... zero hysteresis/zero magnetic memory))).

Now that was informative Tom. Thou in some ways depressing about gold.... especially in or near salt water. Im still thinking I believe like you that small gold can be just as big a pay off at the end of a year. Frankly I like the hunt.... there are a lot of interesting small gold pieces besides rings. Fisher make mine leaning toward Toms small gold aquastar..... id be a happy camper.

NASA-Tom,

Question...I get what you are saying about gold having no "transmit" that lingers beyond when it's being "lit up," unlike other metals we seek. But, I think you said that gold rings are a bit of an exception, in that they "will" transmit for a very brief period after being "lit up," due to the better conductance of the ring-shaped conductor. Am I correct so far?

OK if I'm correct thus far, I guess my question is, why do you find ANY gold that is not "ring shaped," with a PI unit (with its separate xmit and receive periods)? If there is no hysteresis (unless a ring-shaped or round conductor), I'm not sure why you would find any AT ALL, and yet in your example above talking about your AquaStar, clearly you DO. Is it due to the other metals gold is alloyed with, which do have some small amount of "hysteresis?" If so, I guess it would follow therefore that it would be more and more difficult to find these non-round gold items, the purer and purer they are -- to where 24 karat would be essentially un-detectable to a PI machine, even one with the most miniscule pulse delay?

Steve

Im interested to see how Tom answers this one Steve....... because most of the jewelry i find has that continuous round shape....... rings, earrings, coins, earring backs, bracelets....even chains. I have a couple exceptions..... square gold earrings and crosses. Just take a look over of ebay for gold jewelry and see what you find. Charms, pendants and things like gold names.... teeth, which by the way we find very well, maybe the exception. But you just dont know what you dont know Steve....... if we aint finding it, what is it we are missing seems to be your question?

Tom...... maybe Fisher will offer a service to tune one either way like your aquastar for a reasonable fee...... hint hint wink wink.

you can detect shapes that are not round
example this 22k gold tooth under the ruby
the manta takes it very well
but: if you made a ring with this gold, very fine and very wide
he will detect it much further



it is not the weight of the object that determines its depth of acquisition
but its shape
the same broken ring will detect less far
the signal being broken it is distorted

same thing with big rings, they are laying in the sand: head down
by their weight

they are detected vertically / making them harder to take

one last point, I detect this ring of 19gr / 18k
has 7us / about 20 inches
there is no loss of sensitivity with the manta small gold vs big gold at 7us

of course we could still optimize a target type
playing this time on the pulse width
(as already said elsewhere, will be for versions with more digital)

but with the first version, you'll already have something to enjoy



even stronger
the manta is even able to differentiate between 23 and 24k

in iron rejection mode 24k is seen as iron
(no matter the weight / conductivity signal)
the 23 k and lower carats will be taken without problem / so it makes the difference

no other machine does it .....
you take references on aquastar and tdi they are good machines

but manta is something else
another dimension, another world

-------------------------------------------------------------------------------
Detector used : Fisher Aquamanta /

Pulsepower Goldscan 5c / Aquastar / Goldquest SSV3 / Nexus Coronado / Vista Gold

Thanks for the reply, le.jag; I understand from what NASA-Tom said as to why the gold rings would be found to much greater depth than other gold items; still curious though as to whether it is the metal that a particular piece of gold is alloyed with -- metal that DOES exhibit hysteresis -- that allows it to be seen with a PI unit, or whether it's something else...

Meanwhile, the Manta is extremely intriguing. Can you expand upon what you said here..


of course we could still optimize a target type
playing this time on the pulse width
(as already said elsewhere, will be for versions with more digital)

but with the first version, you'll already have something to enjoy

Are you implying that at some point, more digital processing will allow future versions of the Manta to be "optimized," so to speak, by the user, to see specific types of targets? NASA-Tom seemed to be hinting (if I understood him correctly) at a sort of "multi-pulse-delay" PI concept, where instead of the user having to manually change the pulse delay, from one single pulse delay setting to another, that there might be an opportunity build a machine that would transmit at various different pulse delays in rapid succession, and then through digital processing, send a "combination" of the Rx information to the user -- i.e. ID information that results from an analysis of target behavior from each of those multiple different pulse delay transmit/receive cycles...

Steve

Steve make up of the targets and its properties play a big part....... but it seems to me SHAPE does as well. Things like crosses, open jewelry, and even rings with stones turned differently can give a crappy signal and response as opposed to a nice round targets. I like you concept you described.

Tom.... what about multiple timed pulse delay? Two or possibly three pulse delay time sequences cycling one after another.
Can this be achieved with the speed and performance of modern micro processors currently in production in regards to the RX side of pulse delay ?
This seems like such a simple solution to the paradox of small vs large gold.

Up to my ____ in Pulltabs, Grant

1st = Pure gold is a fairly high conductor. And the more 'pure' the gold...…. the further away from the conductivity of the wet-salt it will be; subsequently, the more differentiable it will be to detect IN a wet-salt environment. Sooooooooo………. a (nearly) 24Kt gold nugget is substantially easier to detect in the wet-salt...….. as compared to a 10Kt gold jewelry target of same mass/size …… in the wet-salt environment. In fact …… the 10Kt gold jewelry item …. MUCH closer ...resembles the conductivity of the wet-salt. . . . . . which is not good for us wet-salt beach detectorists.

Moe Conductivity Scale:

Copper = 100
Silver = 106
Gold = 65
Aluminum = 40
Zinc = 28
Nickel = 15
Platinum = 15


2nd = Embodied in the covalent bonding of gold jewelry 'alloy'...….. is a bit of a unique physics phenomenon. When gold is alloyed with copper (which makes our yellow gold jewelry)…….. the overall final resultant conductivity of the gold jewelry item..... is much lower than pure 24Kt gold. The paradox is...…. the fact that PURE gold is a fairly high conductor (65). Copper is a extremely high conductor (100). You would think by virtue of alloying a fairly high conductor (65) with a extremely high conductor (100)...…… the end-resultant would be a conductivity of something 'in-between'...……. say...…… around 80. BUT...…. it is NOT! It's around 40! Hence, the paradox.
And...….. it is a common error of Mfr's to test gold nuggets (which are nearly 24Kt) in a wet-salt environment. First...…. gold nuggets are not found on the beach. Secondly...…. the conductivity of "jewelry" gold is substantially different from gold nuggets. What SHOULD be used for testing purposes by a research & design/development department...….is...…. gold 'jewelry'. Something that is NOT annular. A 10Kt crucifix/cross would be a good start (preferably white gold). . . . . . . for wet-salt R&D.

3rd = Yes...….. a gold ring...…….. by virtue of it's annular shape...……… somewhat creates its own form of delayed-decay-rate ……….. due to: 'closed-loop-of-continuous-continuity'. Which...….. in turn...… makes it ''detectable'' for us detectorists to find. . . . . . . . . subsequently, giving us detectorists the false illusion that "gold rings" are the primary jewelry item that is lost...… and in abundance. . . . . . . . which is statistically in gross error.

4th = Yes...…… we have the technology to 'multiple-timed-sample' the RECEIVE side of the house. The technology indeed exists. After the Xmitter is turned off.... we can take a receive sample at 7uS, 10uS, 15uS and 25uS. Then run all of these data-points through a comparator to ascertain usable intelligence AND not lose depth on larger (coin/ring sized) items.

Steve, Grant, Dew...… VERY valid R&D questions.

Also...……… It would be (electromagnetically/physically) completely incorrect to use a cut piece of aluminum (or aluminum foil) to simulate/emulate a genuine gold crucifix...... for "standardized test-standard" R&D purposes. The test device MUST be real gold jewelry. ((( Gold 'plated' jewelry is also completely incorrect. )))

I noticed ... you didnt mention leads conductivity. I assume because its not in the jewelry make up. We all look for it weight wise.....another flaw to compare it for testing? You talk about crosses.... those gold open earrings can be a challenge also.

steveg Wrote:
-------------------------------------------------------
> Thanks for the reply, le.jag; I understand from wh
> at NASA-Tom said as to why the gold rings would be
> found to much greater depth than other gold items;
> still curious though as to whether it is the metal
> that a particular piece of gold is alloyed with --
> metal that DOES exhibit hysteresis -- that allows
> it to be seen with a PI unit, or whether it's some
> thing else...
>
> Meanwhile, the Manta is extremely intriguing. Can
> you expand upon what you said here..
>
>
> of course we could still optimize a target type
> playing this time on the pulse width
> (as already said elsewhere, will be for versions w
> ith more digital)
>
> but with the first version, you'll already have so
> mething to enjoy
>
> Are you implying that at some point, more digital
> processing will allow future versions of the Manta
> to be "optimized," so to speak, by the user, to se
> e specific types of targets? NASA-Tom seemed to b
> e hinting (if I understood him correctly) at a sor
> t of "multi-pulse-delay" PI concept, where instead
> of the user having to manually change the pulse de
> lay, from one single pulse delay setting to anothe
> r, that there might be an opportunity build a mach
> ine that would transmit at various different pulse
> delays in rapid succession, and then through digit
> al processing, send a "combination" of the Rx info
> rmation to the user -- i.e. ID information that re
> sults from an analysis of target behavior from eac
> h of those multiple different pulse delay transmit
> /receive cycles...
>
> Steve

on the first model to come
the pulse width is fixed
Modular on my proto / but it is not waterproof

and we are limited on the number of buttons / controls

by changing the pulse width while staying at the same delay
we optimize the performance
on light jewels less than 5 gr
or the opposite of the 15/20 gr ring see more

access to internal settings on the next version
will offer this posibility

+ the alternation of delay on the same pulse would probably be possible
but it will slow down the response time ....

to hear a ring at 20 inches you must already sweep slowly

Thanks for all the additional info, NASA-Tom, and LE.JAG.

I really appreciate it. Lots of great, educational info here, and I'm trying to absorb it all...

Steve

NASA-Tom,

Still a bit confused on the hysteresis thing, and PI detecting...

I understand (I think) based on what you have said, that gold does not exhibit hysteresis/delayed decay rate (i.e. it's EM field ceases immediately, the moment its interaction with a transmitted EM field ceases) -- EXCEPT to some degree a "closed loop" like a ring, which will exhibit some degree of lingering EM field after being "lit up" by a transmit field.

That explains in my mind why a gold ring can be found with a PI unit -- but, at the same time, it would suggest to me that a gold item that is not round -- which I believe I understood you to say should have no "hysteresis" -- should NOT be found with a PI unit, given the PI unit characteristic of utilizing non-continuous transmit and receive cycles (as opposed to the continuous/simultaneous transmit and receive characteristics of a VLF unit). In other words, what I have understood here is that as soon as the PI unit stops transmitting, and goes into its receive, or "listening" period, there is nothing to "listen" for, in the case of a non-round gold item, since the gold item is now not transmitting at all. If non-annular gold does not exhibit hysteresis, there would be no "gradually delaying" remnant EM field emanating from the gold item, for the PI unit to receive... ??

However, some non-round gold items ARE found with a PI unit (obviously -- including nuggets). Thus, some "hysteresis" must be occurring, yes? And if so, then my "guess," in my post above, was that presumably the hysteresis (which allows some of these non-round items to be found with a PI unit) must be due the other metals, ALLOYED with the gold item (be it a nugget, or jewelry item), which therefore allows the gold item to exhibit some hysteresis? And if that is correct, then...

I took that further, to assume that if the non-round gold item, say a small crucifix, were PURE gold (i.e. not an alloy), then -- per the idea that gold has no "hysteresis," it should NOT be found with a PI unit.

Somewhere, in all of this that I've written here, there must be some misunderstanding on my part. But I'm not sure where.

I understand why you'd find gold with a VLF -- continuous transmit and receive is happening, so hysteresis is irrelevant.

I understand why you'd find rings deeper/more readily than non-round items, with a VLF (better EM field/eddy current generation with the ring).

I understand that pure gold is a better conductor than most (all?) gold alloys.

BUT -- I am still having trouble understanding WHY you CAN find non-annular gold items with a PI unit -- given that gold does not exhibit hysteresis. If gold does not exhibit a gradual "decay" of its EM field, but instead stops "transmitting" immediately upon the PI unit switching off its "transmit" pulse, then it seems theoretically that the PI would not see the non-round/non-ring-shaped gold item AT ALL...and yet, PI units DO find non-ring-shaped jewelry, and of course are used quite effectively for gold prospecting...

What am I missing, in my understanding?

Steve



Edited 2 time(s). Last edit at 08/13/2018 10:18AM by steveg.

I for one will not be holding my breath waiting to see what size gold 7us gets in salt water that other Pi's can't see. My take on the Manta is that it goes deep on rings and that is what most care about. I hunt fresh water only and have dug hundreds of stud earrings and not one diamond. So my question is, is it worth it to chase them in salt? Sure I would like to find a 3ct G color VVS1 or better diamond but the odds of that happening are slim to none.

Steve...…. VERY good questions/concerns AGAIN!

((( For a moment..... let's forget about annular/rings. )))

Pure gold has nearly exactly zero hysteresis. This is a unalterable property of physics. Diamagnetic material.

Sooooooooo……….. "How do we detect (with a PI) gold items that are not annular?" The answer is: VERY POORLY!

1. SHAPE. One reason is due to the 'shape' of the object. Gold itself will NOT present hysteresis (magnetic memory). But...… the 'shape' of the object plays a role in partially retaining/resonating a small amount of radiated resonance...…. like an antenna...…(even though the gold itself is diamagnetic). Some objects present a poor 'shape' to radiate any energy. . . . . . and other objects may be able to radiate a bit more energy. . . . . like a annular ring.
2. SIZE. This is an interesting one here. The larger the gold object...… the more it 'interferes/imbalances' the Xmit of a PI...…… even though a PI is NOT inductively balanced (I per-se; yet, this can still be one of the contributing factors for detectability.
3. CONDUCTIVITY. The higher the Kt rating of the gold...…. the more diamagnetic it is; yet/however...…. the more 'conductive' it becomes. (((Robbing Peter …… to pay Paul))). The higher the Kt rating/purity of the gold item...…. the lessor the magnetic memory; yet/however, , , , , , the more 'conductive' it becomes...…. tieing in to: 1) size, 2) Xmitter interference, 3) resonance. (((And separating itself out and away from wet-salt...…. in the interest of beach hunters...…. if we are to discuss beach hunting))).


One of the neatest tests you can do is: Go buy a light-weight/hollow 10Kt White Gold Crucifix/Cross...… that stands a little taller then a U.S. Quarter. Try:
........... Prospecting Mode
...…… then Normal Mode
...…… then Salt Mode
...….... then a PI.
((( Don't get upset with the results. )))

Another test is............. Test the performance of a gold ring. Then ..... take a pair of dykes and 'cut' the ring open.......... yet........ keeping the ring in a nearly perfect annular shape. Just don't let the cut ends electrically touch. NOW test the performance of the ring with a detector. This will instill the tuition of "SHAPE". (((You broke the antenna..... with a pair of dykes.,.,.,.,.,.,.,.,.,.,., and now the ring does not want to 'radiate'))). You will clearly see that the gold (ring) has nearly zero hysteresis NOW..... after you dyke it open...…. and .......... it was the SHAPE of the ring ...… that was resonating/radiating...…. until you dyked it open! SHAPE!

SHAPE, SHAPE, SHAPE!



Edited 1 time(s). Last edit at 08/14/2018 02:14AM by NASA-Tom.

You want to find micro-jewelry that is diamagnetic (-X), is not ferromagnetic (+X), has a short resistive (R) low-conductive time-constant only slightly longer than conductive sea water (1uS) which it competes with, has varying resistance and inductance due to micro-jewelry's size, shape, alloy, orientation in the ground. How hard can that be?

Don't know for sure but I'd think the goal is simply to have the PI detector beep on anything that is not ferromagnetic (+X) or better, has a diamagnetic (-X) signature. Seems that is exactly opposite to the inherent capability of the PI; the resistive (R) vanishes quickly (except first order time constants like unbroken rings) while the reactive ferrous time constant drones on. The PI is designed to find ferrous.

I'm sure someone will figure it out. Mixed pulse times and delays, short pulse on-time perhaps to limit magnetic responses and then find a way to measure only the opposing -X component of conductive micro-jewelry or other non-ferrous targets while separating it from the fast-decay resistive signal of salt water.

Probably easier to just build a VLF I-B that can eliminate the positive response to varying salt content in the sea floor and waves and still respond to the tiny resistive phase-shift in micro-jewelry while ignoring all ferromagnetic junk.

NASA-Tom,

SUPER. Thank you! Now I understand much better. Thank you for the clear explanation/education!

Johnnyanglo,

You talked about "fast-decay" saltwater. So, if I understand correctly, it sounds like even if a PI machine were designed to use multiple different pulse delays rapidly/simultaneously and then a comparator to identify targets which have short decay times vs. those with long (including Fe targets), there is still the problem that gold (with its very rapid decay) would share those "rapid decay" characteristics with salt water?

Salt water really throw a monkey wrench into things, when searching for low conductors. Wow.

Steve

John,

HIGHLY appreciated response/input!

Tyndell, from nautilus, built an aqua sound for use here in Fl. Single freq 14khz that you have to GB not only the ground but then the salt water. Are we doing that somewhat with a PI? Is there a way to set it just below the salt response.... much like raw gold hunting? All this raw power ability to see thru minerals....... yet SALT seems to be the one area needing to be over come. If we can ID iron.... why not salt and separate it? Physics right lol.

Apropos 'bump'

Videos of the Impulse AQ are likely to appear - hopefully they will help folks understand what it does and how it does it.

Rick Kempf
Gold Canyon AZ- where there is no gold

Thank you for this thread, I’m excited to wrap my head around this (new to me) technology. I have nothing to add other then a hopeful bump to spark more conversation.
I am wondering, in meantime, if I should invest in an older PI to learn it’s characteristics.