Rcpt Ack of F75 Ltd prototype

Assembled new unit. Bench tested new unit. Nominal performance. Unit passes all test-garden tests.......nominal performance. Set the new Ltd to old F75 'maxed-out' specs.......and positively verified unit is exactly identical to old F75. No need to carry older F75 into the field for head-to-head comparison if this unit (set up with old unit settings) performs exactly the same.

Tomorrow......will commence testing new programs for the 1st time. Will advise.

Tom

Looking forward to your tests Tom. I got my test garden started, nothing complicated yet just a silver dime @ 8" and a copper memorial penny @ 6". They need some time in the ground to build a matrix, as preliminary tests were abysmal (a friend did the same thing and said it took a few months for the matrix to develop so his detectors could see the coins).

I wonder who's testing the T2 Ltd... and if the F75 Ltd is worth $200 more then the T2 Ltd ????

hh,
Brian

Hope you can go to places where the F75, in original modes has been.

Well Tom this is it....I know this is going to take a few days for you to really check the program out and see what it can do for you...In Calif it may be a different story but that won't stop me!

Too bad you can't make a video for YouTube but I am sure you are going to fill a page with info for us..

LowBoy

TAKE A LITTLE TIME KICKBACK AND WATCH SOME OF MY DETECTING VIDEO'S BELOW ON YouTube

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How can you have your pudding if you don’t eat your meat!



Edited 1 time(s). Last edit at 09/13/2010 01:38AM by Lawrenzo.

Tom you have certainly got everyones attention now!!
All the best and here's hoping you come back with some good results.

Thanks.

Take care. Mart.

I'll try to keep everything on this particular thread.

F75 Ltd Proto 1st impressions & Real-World field-test:

FIRST = I am finding no appreciable increase in problematic EMI. Interestingly,
whilst invoking 'bp' mode with ....say; 17% (already encountered/existing)
asymmetrical external white-noise EMI......no additional '%' increase is
encountered. Only a 'volume/amplitude' increase...but not quantity. This is important!

SECOND = In Florida inert dirt.....I have identified several observations ....
worthy of mention. In 'bp' mode...... I am not ascertaining additional 'dirt'
depth on targets. (Many different sweep-speeds tested). What I AM finding.....
is additional air-gap depth. What I mean is: In my test-garden, I have a clad
dime at 12". In any of the old modes (except 'bc'), the Ltd and also the older
F75 will ascertain this dime JUST BARELY.....and SCRUBBING the ground is a
requirement. It is a 'fringe depth' target. Invoking the 'bp' mode.... and the
Ltd will acquire the dime with a much longer duration audio response.... and up
to 3" additional air-gap above the ground. This leads one to believe that the
unit can detect the target to deeper depths. 12" + 3" = 15". Not true. If the
dime is buried to 12.4"........ it is not detectable in ANY mode.....including
the newer modes. I may need to try silica dry-sand beach.....as I have good
reason to believe it may work in that environment.

THIRD = This Ltd model poses a easy 'retrain' to the operator......and is
somewhat intuitive. I am not a 'cache' (or large target) hunter.... but can see merit in 'cl' mode (process).
The 'cl' mode is not usable in fairly trashy areas. It is interesting to
see the lag-time between these two modes.

FOURTH = Real-world hunt. I went back to a 1849-1854 old Fort site that had completely finished producing non-ferrous targets. In a continuous 11-hour hunt....and within the confines of 1/4-acre of property, I managed to find 141 more non-Fe targets, ........ 23 of them were period/era 1849-1854 relics. Several interesting validations and observations were made. ALL of the 141 non-Fe
targets were head-to-head tested; a requirement/prereq for positive validity.
The Ltd performs exactly the same as the old F75....in every respect......whilst
in the old F75's modes (processes). This allowed me to ..... on-the-fly....
switch over to the old process modes, so as to compare to the 2 new modes. The 'cl' mode ......approx 5% of the time had merit......
but it was the 'bp' mode that provided superior results. Of the 141 targets...
ALL of them were at 'fringe' depths. ALL of them. I can not put enough emphasis on this.
Approx 97% of these targets were detectable in the 'pf' & 'de' modes; HOWEVER,
the audio duration length were VERY short. The remaining 3% of the targets were
not discernable enough to qualify as 'detectable' in the pf/de modes. (((I would
venture to say that the 'bp' mode is approx 0.2" deeper on a dime.....in Fla
dirt))). When I would locate a non-Fe target, I would rotate my body around the
target to find best resolution acquisition....and also find the pinnacle
sweep-speed. THEN, I would switch over to de/pf modes. This is somewhat
'cheating' in my books.... as the exact pin-point location of the target is NOW
established... giving the pf/de mode a unrealistic perfect chance at NOW
seeing/detecting the target. You virtually NEVER pass over real-world targets at
the exact/pinnacle/optimal condition every time. Interestingly 97% of the
targets WERE detectable in the old mode; BUT, I will say this in a different
fashion; On aggregate average, the old mode(s) would produce a 7-10mS audio
response over the target (hardly intelligible....and may NOT be enough to
trigger me to dig).... whilst the 'bp' mode would produce a MUCH more
discernable/audibly intelligible response of approx 70-100mS. So many more
targets were 'lit-up' by this 'bp' mode.

Although the detector does not appear to be much deeper....it IS more user
friendly. A slightly slower sweep-speed.....and the Ltd becomes 100% intuitive.

There's a LOT to be said about 141 more targets being found.....in an area that stopped producing targets quite some time ago.

Using a slower sweep-speed than the detector required (whilst 'bp' mode was invoked).....provided a much better human brain comprehension level......as the detector was continuously outputting audio responses.....in this fairly heavy iron trash area. This particular sweep-speed/velocity is probably what a normal detectorist uses anyway. (I know I have a above-average sweep-speed in my daily hunts).

Remember; this is PROTOTYPE testing.... and the final 'released' unit may have differing results; hence, my level of apprehension about posting this info.

Tom

Hi Tom,

Thanks for posting your results.

This is very interesting, such an imperceptible amount of depth increase, which on that merit alone, wouldn't be worth the expenditure, BUT on the fact that the fringe depth targets are lighting up with much more pronounced audio is a very positive result.

One question for you - how was the VDI accuracy on these fringe depth targets? Is it still as jumpy?

Also it sounds like EMI hasn't been reduced, nor increased, BUT I assume the F75 is still a chatter box with maximum settings?

Thanks and HH,
Brian

There seems to be a big difference in the two testers results? Is it the soil?
From what Tom has written I am still on the fence. I know that from my use of the F75 sometimes I will get iffy hits that are scratchy or buzzy sounding. It is hard to know if you should dig those. If I am in an old sight that has relics I will dig as much as I can and some of those fringe targets are nice relics, coins, buttons....But it doesn't seem the new F75 has a huge advantage over the older F75....

We seem to have two different reviews and of course Toms dirt is a lot different from the other persons dirt. And you have to wonder did Fisher design this for in the lab or test in their dirt?

LowBoy

TAKE A LITTLE TIME KICKBACK AND WATCH SOME OF MY DETECTING VIDEO'S BELOW ON YouTube

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If you don’t dig it, then how are you going to know what you’re missing!
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Tom, many thanks for this.
What disc and tone settings did you use in bp mode??

In spite of the fact that Tom's and my results relating to the percentage of targets that were audibly indiscernible in the old modes vs the same targets that were highly discernible in boost was virtually the exact opposite, the actual depth and possibly composition differences of our targets could explain that. And if it's as simple as that, (and we'll never know for sure) wondering about differences in soils and how they might be impacting results could be a moot point. In other words, what if the targets I was recovering via the benefit of the boost mode(s) were just "more fringe or more importantly JUST beyond fringe" than the ones Tom had to work with? If you ignore those different percentages, we actually said very similar things, ie, audible detectability showing a significant difference in allowable cushion in "airspace" of the coil relative to the ground surface. The only difference is I couldn't hear most of mine at all in any of the original modes. I have absolutely no reason to, nor would I doubt the validity of ANY of Tom's observations, but given what I've seen, and it may just be nothing more than the circumstances I just mentioned, then I think you could understand how it's hard for me to comprehend I wasn't reaping the benefit of addtional in ground depth capability. I've been concentrating on hunting in and comparing the differences in original AM and boost AM the last two days and have been seeing virtually the same dynamic differences I saw when doing the same in the discrimination modes. Thanks Tom for taking the time and posting your initial results! The more, the better.

You guys are the only ones that have tested results, just like any machine it takes time to see how these machines differ in different soils....but Tom seemed more conservative in his test.

LowBoy

TAKE A LITTLE TIME KICKBACK AND WATCH SOME OF MY DETECTING VIDEO'S BELOW ON YouTube

[www.youtube.com]

If you don’t dig it, then how are you going to know what you’re missing!
How can you have your pudding if you don’t eat your meat!

As always, I 'push' the detector to its max limits. My Disc was '0' with Sens on '99', 4-tone and no Grnd Bal......as the soil here is inert. There were times when I encountered mental fatigue; subsequently resulting in a Disc change to a setting of '1'. This may not sound like much (to go from Disc '0' to Disc '1').... but it made a tremendous audio reduction (read = fatigue reduction) to the tune of about 45%. What I lost in performance by this minute' change in Disc setting..... I regained the performance in a weaker.... but cleaner (more intelligible) audio presentation. And when I would flip between pf/de/bp modes....all other settings remained the same.....for validity purposes. You must compare apples-to-apples.
One thing worth mentioning, is the fact that the VDI numbers seemed to be a certain percentage more accurate in the 'boost' mode. This is a bit surprising.....as; boosting extremely weak/tiny signals that just simply look like 'noise'..... and to give greater VDI accuracy, is unexpectedly phenomenal. Even on partially masked targets. VDI numbers were still 'jumpy'.... but in a narrower range.......on nearly every non-ferrous target. And.......keep in mind......ALL of the targets recovered were 'fringe depth' targets. Merit/credit is due.
I think Brad & I achieved nearly identical results. . . . dirt differences aside.

One thing I always ask myself; "If given a choice, would you choose new widget over the old tried-n-true......language understood.......comfort-zone familiar ... older unit"? In furtherence; I also ask myself if there remains a few 'good' points/tools with the older detector vs. the newer detector.......rendering BOTH units as 'required keepers'......and BOTH units must be brought out into the field each/every time?
This is a case, thus far, hands down......the new unit exactly mimics the old unit PLUS has a couple more useful tools (in the form of 'process' programs)....... that completel renders the older generation unit as "not needed" status. With every amount of 'forced failure' I pushed into the Ltd yesterday, it performed exactly like the old F75.....but with the new tools that I will not live without.
I'm quite disappointed that the new Ltd does not go 1" deeper on a dime. My EXTERNALLY preprogrammed expectations were 'let down'. HOWEVER; driving 2-1/2 hours home last night gave me time to recap & think........... the reality of finding 141 more non-ferrous targets.........23 of them are 'keeper' relics....in an area that was completely sanatized w/older F75......certainly has 'driven a point home'. A few 'random' targets found..... and I would have written-off these few targets as 'randomly missed'. But...... 141 non-ferrous targets is not a 'random few'. Going back to this same area to hunt.....I expected the only targets that I 'might' find..... would only be the 'fringe' targets.... as this area has been sanatized by the earlier F75. --- Even more importantly....... was the head-to-head comparison that 'finalized' the quantification/qualification/validity of the new program(s). When a 'sanatized' site becomes 'virgin' again..... a 'bottom line' is drawn in the sand.

Tom

I can now see two obvious differences in how/where we performed our tests. One is the inert soil you have and the dirt I have which as I've stated in the past is 65 to 85 ground phase but acts strangely similar around its effect on targets to that of the orange iron mineralized the dirt I encounter when I go to Culpeper, VA. The other is your settings. No way can I run as hot as you do, factoring degree of audio fatigue or not. So in your opinion, is it possible that either, or the combination of both, could yield (some/more) inground depth benefit to me but not you? For example, I can see the possibility that when one is forced to run more nominal settings such as I do, the targets won't be "lit up" as much in the non-boost mode(s) which might be responsible for my NOT hearing a lot of targets at all unless in boost. Thoughts? Again, TIA for your time and expertise.

This is entirely possible.... and even probable....in some cases. Something I learned a couple of years ago about the F75......and, initially.... did not make sense. I had detected a small non-ferrous button at a true 13". This button alone.....at 13"...... with nothing around it, would be undetectable; BUT, there was a very small piece of iron at nearly the same depth..... maybe 1/4" less depth........ and about 1.5" off to one side. The 'combined' signal from both targets.... caused the F75 to respond with a audio report......and a non-ferrous ID.....but the numbers were all over the board. The 'combined' targets gave a signal strength just strong enough for the detector to barely report a audio response. Without the small piece of iron..... the small button would have remained undetected at 13". The moral of the story; mineralization and/or small ferrite targets can sometimes enhance depth abilities. Moisture content of dirt can also enhance EM conduction 'sometimes'.

Tom

Brad and Tom do you know if Fisher fixed the F75 disc "glitch" on the new F75 Ltd??

If you ran the disc at 4 or higher, you lost ~ 4" of depth due to a software bug. Apparently they were never able to figure out how to fix the code on the F75.

Brian

I've been pondering on the exact answer you've given here.
The main reason Tom has not seen as much improvements in depth is the fact he usually runs the LTD at max sensitivity and low discrimination settings in both the boost mode and de/pf modes.

I also can't run at 99 % sensitivity and seldom run my discrimination below 2-3 for long periods of time (just to much for my ears to comprehend).

If you would, the next you're hunting and locate what you believe to be a deep target in boost mode, when you switch to standard de mode, drop the discrimination to 0 and recheck the target for a response.


Thanks in advance
Mark

BuckeyeBrad Wrote:
-------------------------------------------------------
> I can now see two obvious differences in how/where
> we performed our tests. One is the inert soil you
> have and the dirt I have which as I've stated in
> the past is 65 to 85 ground phase but acts
> strangely similar around its effect on targets to
> that of the orange iron mineralized the dirt I
> encounter when I go to Culpeper, VA. The other is
> your settings. No way can I run as hot as you do,
> factoring degree of audio fatigue or not. So in
> your opinion, is it possible that either, or the
> combination of both, could yield (some/more)
> inground depth benefit to me but not you? For
> example, I can see the possibility that when one
> is forced to run more nominal settings such as I
> do, the targets won't be "lit up" as much in the
> non-boost mode(s) which might be responsible for
> my NOT hearing a lot of targets at all unless in
> boost. Thoughts? Again, TIA for your time and
> expertise.

Tom, can you describe how the LTD performed in your test best over co-located (partially masked) targets in the new 'BP' mode? I'm wondering if the new circuit slows the machine down to a point where the fast unmasking capabilities are compromised.

Cal_cobra Wrote:
-------------------------------------------------------
> Brad and Tom do you know if Fisher fixed the F75
> disc "glitch" on the new F75 Ltd??
>
> If you ran the disc at 4 or higher, you lost ~ 4"
> of depth due to a software bug. Apparently they
> were never able to figure out how to fix the code
> on the F75.
>
> Brian

Hey... I never realized this was a glitch, I thought it was by design. I am very much interested the answer to this question. I have placed an order for an F75 LTD. I sold my F75 a while back to a buddy who really loved it. I kept my T2 in case I needed this type machine. Now I am going to have an F75 again... and an improved one at that...

Didn't the boost "malfunction" kick in at 50 or so? I may be confusing it with the disc level on the T2... so correct me if I am wrong.

Thanks!

Julien

Jumping from a Disc of '4' to a Disc of '5' is only approx 2% loss of total performance....at least in Florida tame soil (and Chicago dirt).

Running the new 'bp' mode in the co-located Fe vs. dime test was interesting. With a sweep speed that is pinnacle for the de/pf modes........then switching over to the new 'bp' mode..... and the audio length was shortened by approx 15%; yet, still fully intelligible. Slowing the coil sweep-speed down by 15%.... and the audio duration length nearly DOUBLED! Yes, a paradox. It should have naturally increased in duration/length by (logically) 15%. Not true! --VERY GOOD QUESTION!

Tom

Tom,

I love my F-75 and a few days ago couldn't imagine parting ways with it. But your report just made me drive towards the edge of getting the LTD. I like the idea of the LTD being exactly as the original F-75 in the other modes. That tells me that if I get the LTD, that I wont be having "any less" of a machine than what I have now, if I find the new modes not up to par, and thus me not having to sell the LTD to regain my F-75.

It's amazing the difference in soils. I am a relic guy and don't even have a coin buried in my test garden. I do however, have a normal size Eagle button buried at exactly 9" measured. The dirt here reads at .3 to 1 on the FeMeter. My F-75 maxxed out in motion all metal, will not consistently respond on the button. You can sometimes get a half whimper of a signal with no visual ID on the screen. My TDI on the other hand, will hammer home on the button.

The F-75s language to me, is tried and true. I understand it. The TDI is still new and foreign to me. I've found though that on lead type targets like bullets, that the TDI and F-75 are very much equal. I give the TDI the advantage in the heavier iron dirt though just because some places the F-75 doesn't seem to be able to stay stable and ground balanced. It is the lower conductors that the TDI excels on, over the F-75 and thus I am curious to see if the LTD would up the ante in gaining some ground on the TDI in target response in iron dirt with the new mode.

NASA-Tom Wrote:
-------------------------------------------------------
> Slowing the coil sweep-speed down by 15%....
> and the audio duration length nearly DOUBLED!
>
> Tom

Are we at Explorer sweep speeds now or is it still substantially faster?

And... do you believe that the 'bp' mode makes the DE/JE modes essentially obsolete? If not, where do they still excel?

There is no such glitch on my F75 must be someone trying to put down the F75

LowBoy

TAKE A LITTLE TIME KICKBACK AND WATCH SOME OF MY DETECTING VIDEO'S BELOW ON YouTube

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If you don’t dig it, then how are you going to know what you’re missing!
How can you have your pudding if you don’t eat your meat!

Lawrenzo (and anyone else interested) read this post about the F75 SW glitch, it's a well known issue:

[www.findmall.com]

Don't see what you are talking about?

LowBoy

TAKE A LITTLE TIME KICKBACK AND WATCH SOME OF MY DETECTING VIDEO'S BELOW ON YouTube

[www.youtube.com]

If you don’t dig it, then how are you going to know what you’re missing!
How can you have your pudding if you don’t eat your meat!

Start with post seven and read on from there, it's well discussed (there's even a graph to illustrate the issue).



Edited 1 time(s). Last edit at 09/22/2009 04:11AM by Cal_cobra.

If this is still about the F75 I never had a problem and never read about one and Tom never said anything about it.

LowBoy

TAKE A LITTLE TIME KICKBACK AND WATCH SOME OF MY DETECTING VIDEO'S BELOW ON YouTube

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If you don’t dig it, then how are you going to know what you’re missing!
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This might have applied to the first F75s to go into production.
That chart does not work for my F75 .
To only get 7,5 inches at disc of 6 the sens would have to be in around 60
Thanks Mike

I purchased my first 75 the first month they were available and although there was depth differences when in real low/no discrimination, the chart you're referring to showed a lot more difference than mine does. The 75 LTD proto shows almost no difference in depth (there is a little difference in target response duration) but still has considerable difference IN SOME ENVIRONMENTS in the sensitivity to noise at "0" vs "6".

Daniel....I think you will acquire a 'marked' improvement w/Ltd......and yes, I think it's QUITE important to still retain comfort-zone/resistant-to-change/old-familiar already-existing old modes. Your TDI is a PI.....and.......the worse the soil.....the better it'll trump all other VLF units. However; I STILL don't trust the ID circuitry.

As far as Ltd sweep-speed whilst in 'bp' mode,,,,, yes, the speed would be slightly faster than the ML Explorer......BUT....it is YOU that will subconsciously adjust your sweep speed. When you instantly discover that a lot is taking place in your headphones; it is all-too intuitive/instinctive that you will naturally slow down.....so as to have more targets to select from. This applies to MOST of the 'types' of areas we like to hunt.

In about 10-12 hours, I have another battery of definitive tests for the Ltd.
* 'JE' mode vs 'bp' mode Sens to small low conductors.
* ID accuracy at max depth.....w/no masking.
* Nickel depth & dime depth.

I'd like to play more with 'CL' mode.... but will not have proper location (yet).

As more time elapses.....it's really starting to sink-in ...about those 141 non-ferrous targets being found behind the previous Gen F75. A true feat. I'm certain of my previous abilities having 'sanitized' this exact location with old Gen F75.

Further evaluation very soon!

Tom

Tom, Brad, Lawrenzo and others, thanks for the informative thread! This is becoming THE place to come for new F75LTD info. Personally, I love my F75 and it's the best detector I have ever used. Hearing this positive feedback (from people I trust) makes me want to get this new model. The way I see it, if I can recover just ONE more nice relic from each of my pounded sites - that would make this beefed up detector worth it - not from a "cost - benefit" standpoint, but from a history and hobby perspective.

Couple of questions:

Is the F75LTD available in regular F75 colors or is it only in cammo?

How would you rate performance improvements on a more "tame" setting - for instance: JE 85 disc 9 ? vs. boost mode?

Does this machine have the EXACT same sound and feel of the old one?

What exactly does limited edition mean - are they really only going to make limited amounts of machines? Seems kind of strange.


So if the F75LTD finds more and it maintains the quick recovery speed in the new mode - I'm buying one.

Ian



Edited 2 time(s). Last edit at 09/23/2009 10:20PM by saginawian.