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Rcpt Ack of F75 Ltd prototype

Posted by NASA-Tom 
Re: Rcpt Ack of F75 Ltd prototype
July 01, 2015 10:48PM
The FA mode on the LTD2 is quiet impressive on a complex ferrous/high conductor target like what Tom describes oin his DVD. It's not deep, maybe 4-6" in my red clay, but it takes to the Minelab wiggle quite well. Just don't jack the sensitivity too high and damage the audio.

Someone (me) needs to do a video...
Re: Rcpt Ack of F75 Ltd prototype
July 02, 2015 11:58AM
The FA mode certainly has attributes...... for present detecting and future technology.
Re: Rcpt Ack of F75 Ltd prototype
July 02, 2015 12:12PM
The FA mode seems to distort the audio at high sensitivities just like the CL mode. Yet both processes are at the opposite end of the design intent spectrum.

The BP and CL modes seem to operate differently than what was on the non-DST units. Maybe that's the effect of the noise cancellation or the effect of an overall software "freshening." Whatever the reason, the DST machine operates, in my hands, significantly different than my original CAMO F75.

And that's a good thing...



Edited 1 time(s). Last edit at 07/02/2015 01:16PM by go-rebels.
Re: Rcpt Ack of F75 Ltd prototype
July 02, 2015 12:57PM
All you long time f-75, f-75LTD users, should I be kicking myself for not getting my LTD-one upgraded to a LTD-two?

Go-reb, I see your vote is.. I should wander up to the ole boot tree and pull the rope a few times........... So that's 1 for should have.
Re: Rcpt Ack of F75 Ltd prototype
July 02, 2015 02:03PM
I'm not a long time originally boosted unit user, but will say. If a person does the majority of their hunting near/close to towns, cities where EMI is generally more prevalent---it's a no-brainer get the DST upgraded units.

Now if one hunts more rural spots using AM- a no brainer- keep the originally boosted unit-no DST.

One thing is recovery delay is slower on DST units. BP process with DST unit quite a bit slower than non DST unit. And maybe this was the reason for the FA process. Only speculation coming from me.
Re: Rcpt Ack of F75 Ltd prototype
August 24, 2015 05:36PM
I have been hunting with a F75 (& LTD) platform for nearly a decade now. There are some very specific data-point(s) that I have quested...... and have finally acquired. Low conductors that fall into the conductivity range of U.S. 3-Cent Nickels to U.S. $1 gold coins (Types 1, 2, & 3). On a F70/F75 platform..... this ID spectrum..... ranges in the narrow conductive band VDI ID range of '20 - 26' ; respectively. This is in the middle of 'foil' conductivity range. The data that I have been seeking is............... targets that fall into this narrow low-conductive band-width that are near (or at) fringe detection depths......... WHAT is the 'average propensity' for these targets to "down-average' ID, ID properly....... or 'up-average' ID. In my inert Florida dirt...... these fringe depth low-conductors will 'up-average' ID 72% of the time. The only targets that qualify for data input measurement...... are targets that are not near any other target, not near iron nail(s)....... and not in rusted/decomposed (flecks/flakes) oxides of iron. This fairly high up-averaging propensity also holds true for T2's. A lot of this data does transfer into other platforms/detectors....... especially the higher freq units.

I had concern about these low-conductor targets nearly always wanting to 'down-average'..... right into the iron range......... which........... (now)........... is not true.

Now....... the equation completely changes if you are in red lateritic iron oxide (and/or magnetite) soils........ whereby......... regardless of target conductivity............................................. the deeper the target, the greater the chance for the target to read/ID as 'iron'.
Re: Rcpt Ack of F75 Ltd prototype
August 24, 2015 08:24PM
Hey Tom,
Just have a few questions to help my understanding. You use the terms "up-average" and "down-average" but unless you are talking about co-located items, "x-average" does not really apply, does it? And you say you are not including data from, as I understand it, co-located targets. So, aren't you really using up-average and down-average to mean "give a conductivity reading at depth higher than or lower than the target does in air or on the surface?"

The above assumes that when you say you don't use as data those occurrences where the target is near iron nails that you are also saying you do not use the data when the target is near iron of any form.

Please correct me if I am misunderstanding you.

Thanks, Tom.

Wayne

Pleasant Garden, NC
AT Max, Nokta Impact, MX Sport, Nokta FORS Relic, GPX 4800, Infinium, Racer, Deus, F75SE, Nautilus DMC II (order of acquisition, last to first)

Does an archeologist argue with a plow? A bureaucrat with a bulldozer?
Re: Rcpt Ack of F75 Ltd prototype
August 25, 2015 03:36PM
Wayne,

Multiple targets under the coil will certainly skew ID data. . . . . and this induces a immeasurable variable(s). BUT....... what I am conveying....... and what my intent is........ is to see/witness/document the natural ID 'up-averaging' of just the single/solo low conductor target at fringe depths. A U.S. 3-Cent nickel will produce/generate a reliable/accurate ID of '21' on a F75/F70........ even at 7" deep. . . . . . with no other metallic target nearby. As this target gets deeper....... the 3-Cent nickel will start to ID something OTHER THAN the correct '21' reading....... and this is with no other target nearby. This is to say........ (72% of the time)........ the 3-Cent nickel will give a ID higher than '21'. In other words....... you do NOT need another target in close proximity...... to cause these higher freq units to up-average/down-average the ID........ especially with lower conductor targets.
Re: Rcpt Ack of F75 Ltd prototype
September 12, 2015 07:57PM
Tom, I was surprised by the Fisher website in that it did not list jewelry hunting as a recommended use of the F75 ltd. How do you feel it performs in this area?
Re: Rcpt Ack of F75 Ltd prototype
September 13, 2015 02:16AM
It's spectacular for (low-conductive) jewelry...... especially in 'bp' mode. It's not a micro-jewelry hunter........ nor will it hunt wet salt; yet, for nearly all other applications, , , , it's particularly good. Some skillset is required (or training), , , , due to it's sensitivity levels; yet, can easily be learned.
Re: Rcpt Ack of F75 Ltd prototype
January 04, 2016 12:13PM
I have been waiting for very specific weather & atmospheric conditions ...... in order to test a theory.... and hunt a specific site. The 'conditions requirement' were met. Heavy cloud cover....and a few days of nearly continuous light rain. The test would be specific to the hyper-gain F75 LTD (in boost process mode); yet, my theory would also (secondarily) apply to all other detectors............. but............ to a lessor degree..... due to a lack of their hyper-gain capabilities. This is what determined the 'why' rationale.... for making this entry onto this specific thread.

The location is in a fairly rural area....... and the area of land to be detected is a 70' x 100' parcel.... in the middle of a large open field. All non-ferrous targets had previously been detected and removed. My purpose of this test (quest) is specific to EMI. . . . and the hindrances thereof. Under normal conditions at this specific site, EMI is categorized/rated as 'low'. During my recent test........... specifically due to the current-day weather & atmospheric conditions.......... the EMI was 'very low'. Yes, these terms: "low" and "very low" .... are vague and interpretive; yet, as of this moment, I have no gauge/measurement tool to 'measure-and-clarify' .... for a more solid base-reference explanation.

In any regard ........ in a nutshell............ I was (on average) ascertaining 0.7" greater depth.......... due specifically to reduced EMI conditions. And what a huge difference just seven-tenths ( 0.7" ) additional detection depth can make. 72 more non-ferrous targets were recovered in this 70' x 100' area. Targets ranged in size from .22 Short projectiles (29 Gr).... to .22 Short, Long/Long Rifle empty brass cases........ to a half dollar sized melted lead blob. There appeared to be a bit more bias/propensity towards detecting very small sized (and lower conductor) targets....... due to reduced EMI conditions; yet, I can not 'qualify' this statement.......... as this particular site 'might' be presenting a higher volume of these very small targets...... and a lower volume of larger targets. ((( The jury is not out yet. ))).

I only had one other detector with me....on this specific hunt. The XP GMP. I had zero intentions of head-to-head testing; yet, curiosity prevailed. At the very end of the hunt........ I marked 6 targets with the F75. Only one of the six targets could be detected by the GMP. It happened to be the smallest (and lowest conductive) target. . . . . . most probably due to the higher operating freq (18 Khz) of the GMP. Had the mineralization been greater, I speculate the GMP would have presented very different (more positive) results.

Hyper gain has substantial value-added application ...... but only with intel & skillset.



Edited 1 time(s). Last edit at 01/04/2016 12:19PM by NASA-Tom.
Re: Rcpt Ack of F75 Ltd prototype
January 08, 2016 12:11AM
Good Info Tom thank for the update..

Would be nice to see the F75 and other FTP units become more GROUND REACTIVE!!

yet its hard to not grab the 75 .Still a force to be reckoned with..

Though I find myself liking the Pre DTS for the Pure HYPER feel..

Hard to beat hyper gain overdrive in iron..IF ONE LISTEN'S..

Keith

“I don't care that they stole my idea . . I care that they don't have any of their own”
-Nikola Tesla
Re: Rcpt Ack of F75 Ltd prototype
January 08, 2016 12:35AM
Keith,

Will you, or someone else, mind clarifying a bit what you mean by a detector being "more ground reactive?"

Steve
Re: Rcpt Ack of F75 Ltd prototype
January 08, 2016 01:59AM
we have started seeing machines in the last few Years Steve offer a Disc mode that in alot of ways resembles a all metal disc mode in a more truer since thsn just full accept of old ..

And by this I mean having the ability to have zero disc and still have the say two tone audio report that is very conveying to the soil .So GROUND REACTIVE comes to mind.

This FEEL of more of an all metal disc is done by less filtering of the disc channel..Very much a BLEEDY Filter setup..

So when you scan the ground even though we are in disc mode we get to hear the Ground Noise even without a Negative ground setting..(which offers a ground reactivity in Disc mode by the way)..But these newer units are doing it by just less filtering and dead on ground bal..

the AT series offers this feel

The XPs offer this feel

The DeepTechs offer this feel..

What does this Ground reactivity offer??

Well the less filter of ground signal can offer Mineral SEE THROUGH..

So while we dont have deeper units per se in terms of more distance.. we do have more depth in terms of less mineral masking..

Mineral will cause Mis I.D. for sure but it will also cause complete target ignore if its strong enough..

A disc mode on a detector can cancel the mineral noise to a huge extent..and by doing this it can completely remove legitimate targets intermingled in the ground mineral..

So add less filter but not too little ..jsut enough to allow some Intelligent noise into the audio if the disc is Wide open...as pops clicks and even wah wah sounds or even constant rolling noise..By allowing this to happen we then can hear the slight reports of targets that would otherwise be removed through heavy filter..We get to hear the targets BLEED In so to speak....So now we have more usable depth..

The FTP's seems to filter a lot of ground BLEED..Hopefully that will change in the future!


These new Ground Reactive machine's are as Jeb Stuart would say to his troopers Qui Vive!!.. French for ON ALERT....Jeb was quite the flamboyant cavalryman!....LOL!!

Keith








.

“I don't care that they stole my idea . . I care that they don't have any of their own”
-Nikola Tesla
Re: Rcpt Ack of F75 Ltd prototype
January 08, 2016 03:02AM
Keith.

INTERESTING. Thank you.

However, I think such an ability, to decipher "good target" hits from "mineral noise" that has been allowed by the designers of the machine to "come through," audibly, to a detectorist...that's way beyond what I'm capable of. I have a hard enough time, on an Explorer, for instance, trying to listen for, and sort out, the hints of a deep coin amongst the high-tone-falsing of deep, rusted, bent iron. And yet YOU run an Explorer WIDE OPEN, no disc, no iron mask, and can hear the good targets from amongst the bad. That's right up there with cold fusion and anti-matter, for me! I mean, I tried that -- and when I did, the problem was that with no iron mask imposed on the machine, a 24-29 target (nail) reports, when in Conductive sounds, with the sound -- to my ears -- as an 03-29 target (silver dime). Obviously in Conductive sounds, the tone is driven by that "29" conductive number, and some nails sounded exactly as a silver coin, to my (apparently defective) ears!

So, therefore, I have decided that my ears simply "can't discern" certain nuances that yours can -- and as such, the thought of trying to make my ears filter the sounds of fringe-depth coins from GROUND NOISE? Yikes...

I don't think I can do that. But -- for those who can, I can see where what you are describing as "ground reactivity" being heard, would be of benefit.

Thanks for the great explanation, Keith.

Steve



Edited 1 time(s). Last edit at 01/08/2016 07:34PM by steveg.
Re: Rcpt Ack of F75 Ltd prototype
January 08, 2016 03:38AM
Well Steve..

Not sure its acute hearing or just the ability that its once you hear it thousands of times you know it..

Most of the Full open disc machines with multi and or flutey tones and such for me personally is you become accustom to the DIN of noise then the slightly different spike in audio sort of Piques your senses..


But I promise the VLF Machines that are becoming GROUND REACTIVE are not like a FBS Explorer wide open screen multi tone...the VLF is more behaved and more intelligent audio wise..

I'll take your response as a duly noted Compliment but undeserving all the same.LOL!!!.;;THANK YOU!!!

Keith

“I don't care that they stole my idea . . I care that they don't have any of their own”
-Nikola Tesla
Re: Rcpt Ack of F75 Ltd prototype
January 08, 2016 06:18PM
Keith,

On the non-DST F75's.......... there is a night-n-day differnece between a Disc setting of '0' and a Disc setting of '1'. . . . . whereby......... the Disc setting of '0'........... expresses all minerals encountered. (Whilst in ID mode).
Re: Rcpt Ack of F75 Ltd prototype
January 08, 2016 06:29PM
Good Info Tom...

Yes I like Zero Disc on the 75 Non DST when I can get a way with it..EMI wise especially..

Yet For lack of better words the FTP's dont have that RAW ground reaction feel like some of the newer offerings of late..

Picture painting audio coupled to Bleedy Filter's..

I would also like to see some Blendable Audio instead of the One tone at a time report...

I think or better yet hope we see some audio advances in the Future FTP products..

That blending and bleeding can paint quite the picture in terms of giving us a truer all metal in disc feel..

Thank you for the reply Tom~

Keith

“I don't care that they stole my idea . . I care that they don't have any of their own”
-Nikola Tesla
Re: Rcpt Ack of F75 Ltd prototype
January 09, 2016 12:51AM
Keith --

Thanks for the additional info.

You said...

Quote

Most of the Full open disc machines with multi and or flutey tones and such for me personally is you become accustom to the DIN of noise then the slightly different spike in audio sort of Piques your senses..

But I promise the VLF Machines that are becoming GROUND REACTIVE are not like a FBS Explorer wide open screen multi tone...the VLF is more behaved and more intelligent audio wise..

I can understand what you are saying about the background noise becoming a "din," and it's "something different" from the background noise you are listening for. That makes sense to me, and I can relate; running an Explorer hot, there is a background "din" -- over and above just the threshold hum -- of chirps and such that you just learn to TREAT as a sort of "threshold," while listening for something "different." So, I get that. And it's encouraging that you say that these "ground reactive" VLF machines you are speaking of do NOT present the same challenges as running a FBS machine wide open, multi-tone. Perhaps, just maybe, something more "well-behaved" and "intelligent," I could learn to decipher as you've described it.

Still, though, anyone who can run an Explorer on Conductive multi-tones, wide open, and hear the difference between a deep, rusty, bent nail and a copper/silver coin, when both of which may present a 28 or 29 conductive number? That's on another level, that I can't imagine ever reaching, no matter HOW many years I might eventually have under my belt... LOL! You under-sell your ears, my friend!

Steve



Edited 1 time(s). Last edit at 01/09/2016 12:52AM by steveg.
Re: Rcpt Ack of F75 Ltd prototype
May 25, 2017 11:25AM
Bump..........
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