Fisher F75 interesting information and tips on how to setup and run your F75 or F75 LTD by Tom D. A must read for all new F75 users.
I got the T2 with all the updates and have to say it is a very good detector.
Here is what the F75 has over the T2
The always on backlight is liked by some users but disliked by others. I hunt by tone ID, so having no backlight on the T2 is not a problem. Some wish they could turn off the light of the F75.
First T2s didn't ID as deep as the F75, but the newer T2s ID as well as the F75.
The F75 Handles interference a little better, but i feel that the T2 has a little more punch if you can run ist hot.
The F75 has selectable processing modes that are independant from the Tone ID the T2s processing mode is tied to the tone ID.
The gain and depth on the T2 depends on the Disc setting. It seems you have high gain from 0 to 10, lower from 10 to 20 and higher from 20 + again. I like to use disc 0 with 2+ Tones.
Depth on the fly meter on the F75 and signal strength on the T2.
Static All Metal Mode on the F75, not on the T2.
Last setting memory on the F75, not on T2.
First I thought ist is better to have last setting memory, but due to notch and disc setup on the F75 you may get confused what you did to the detector and a program error is still there if you turn is on again. On the other hand, programming the 3 settings on the T2 is done is under 10 seconds.
The F75 has only 15 numbers for iron and the T2 40 numbers for the iron range. If you have good target mixed in with iron the T2 does a better job than the F75.
Notch System on the F75, only Disc on T2. I never liked Notch because you can only Notch out a group of numbers. I rather go by the VDI numbers, because often one number up or down from pulltab can be the gold ring.
The T2 has less feature, but is easier to use and setup. I year ago I thought the F75 is best for me, but now I use the T2 with the new 5" DD coil most of the time.
BTW, if you don't have the new 5" DD coil for the F75 or T2 you may want to get one. It separates extremly well and the depth is hard to believe for a coil of that size.
I have been running various F-75 Proto's for several months now.... and I must say there is legitimate justification as to why I DID NOT report any initial findings with early generation Proto's.... as the final product differs dramatically from the original Proto, in respect to operating characteristics.
In a nut-shell:
* F-75 most closely resembles T-Square (T-2), but with much more power/Sens.
* F-75 is approx. 1.5" deeper on a U.S. dime vs. T-2.
* T-2 is High Resolution Iron Discrimination (Disc of: 00 - 40).
* F-75 is High Resolution Aluminum Discrimination (Iron Disc is 00 - 15).
* F-75 has up to 300% greater sensitivity to small gold (vs. T-2).
* F-75 has tremendous gain on small gold when Disc is reduced to '0'.
* F-75 incorporates CZ-3D "old coins" Specs, 4-Tone, VCO pinpoint, nickel hi-tone. ---Nickel window is slightly widened.... and 'old generation' coins audibly report as 3rd-highest tone in the 4-tone mode. (( Sounds similar to the "relic" tone on CZ-70 )). All 4 tones similar to CZ-70. (Comfort zone not infringed).
* F-75 & T-2 has microprocessor (identical - audible) extremely enhanced adjacent target separation characteristics..... as fast as...and possibly faster then human brain comprehension.
* F-75 & T-2 coil electromagnetic footprint is identical. ( Tightest DD footprint in the industry ).
* F-75 vs. T-2 (in 2, 3 & 4 tone modes) Identical target separation (in iron or alum trash).... except F-75 has more sensitivity,,,,giving better audible resolution on non-Fe targets (especially deeper targets).
* F-75 VDI on Cu dime = '72' and on Ag dime = '74'. (High Resolution Aluminum Discrimination can also be viewed upon as: High Resolution Coins Discrimination).
* F-75 is a noisy machine due to extreme levels of Sensitivity capabilities ....and,,,, to a beginner/newbie, it may be quite difficult to understand its language. T-2 users will have zero problems - seemless transition. Remember; In most cases the 'chatter' you hear with the T-2/F-75 (in actuality) is not 'chatter'.... rather, it is tiny (or deep) pieces of metal. And also remember (especially w/F-75) it allows the operator to "overdrive" the Sensitivity because there are some physical areas where this is do'able (and prefered).
* F-75 has slightly less electrical/electrostatic interference problems vs. T-2 & Coin$trike.
* T-2 turned out to be a very serious 'relic' hunter (not intensionally). F-75 was intended/targeted to be more of a 'coins' hunter; however, in reality, I have verified it is a 'coins' hunter (more so then T-2) and a premium 'relic' hunter.
* Be careful; 'masked and/or deep coins' will give low 'Confidence' LCD readings.
* Moderately Fe-masked targets are mostly undetectable to other detectors, whereas F-75 will report the non-ferrous target in co-locate with iron. In these cases, do not rely on VDI numbers.... as the F-75 will homogenate/mix...and usually "up-average" the VDI numeric reading. Most places hunted, masking is severe.
* F-75 has identical depth (with proper ID) capabilities to CZ (w/8" coil) in Florida inert soil.
* F-75 has nearly identical depth (with proper ID) capabilities to CZ in Georgia red laterite. (Some areas the Fe3O4 (magnetite) LCD bar-graph easily pegged w/T-2 & F-75).
* Of noteworthy interest; T-2 & F-75 are single Freq units.... and parallel the multi-freq CZ in the department of depth.
* F-75 not indended as a wet-salt beach unit; however, performance is okay.
* Dry sand performance is tremendous if config'd properly.
* CZ & F-75 on coin-sized targets (in most cases) have nearly identical depth capabilities and overall performance (in most parts of the country); HOWEVER, in medium-light, medium, medium-heavy & heavy trash areas the F-75 is far superior in adjacent target separation capabilities. Once again; "depth" vs. "EFFECTIVE depth" (See Fisher Intelligence - 6th edition for expanded explanation).
* In clear/trash-free fields in Georgia severe red lateritic dirt, Minelab Explorer is superior to F-75/CZ/T-2. In same dirt, ...in medium-low, medium, medium-high & high trash areas the F-75 (& T-2) are far superior to all others (including Minelab & CZ). Microprocessor of Minelab is unacceptably slow. Keep in mind; approx 80% of the areas we hunt are medium-low (and higher) trash areas. Where people cohabit the most..... is where most finds will be located.
* In a Fe trashy area, hunting behind a CZ/Explorer..... the F-75 will give appearance the area may have never been hunted.
On a personal note: Hunted an old home-site in Georgia. Heavily nail infested. Explorer was quiet. Excessively quiet. Audio threshold was constantly nulled (due to Fe nail infestation dirt). CZ was 'chattery'. Any/All CZ & Explorer performance were 'shut-down' due to severe handicap in nails. F-75 was 'noisy' but found MANY non-ferrous targets that CZ & Exp could not see (head-to-head verified/validated). F-75 could see non-Fe targets to depths of approx 3"...where as CZ & Exp could only see surface targets semi-reliably. ---- Hunted several other areas with similar performance. ...Explorer is too slow to 'reset' between adjacent targets.
* Deliberately run the F-75 a bit noisy.
* Optional coils to follow. Be patient.
Thomas J. Dankowski F75 going crazy ? Read this :
The number one problem seems to be that the F75 can go crazy and beeps constantly and the VDI numbers jump all over the place.
Well....that happened to me and my F75 too.
Nothing was wrong with the detector. You just have to know that the F75 picks up sources of interference in the high gain modes.
Next you need to know what are the high gain modes.
1. High gain in DE mode kicks in if you have the disc lower than 5 or higher than 19.
2. The JE mode is a total high gain mode no matter what disc setting you use.
In a perfect world the JE mode with a high sensitivity setting would get us the best depth. Or the DE mode with the disc lower than 5 or higher than 19.
Now how do you find out if you have interference sources nearby ?
Turn on the F75 with a sensitivity setting of about 70 and lift the coil to waist level. Now select JE mode, or DE mode with the disc lower than 5. If the F75 goes crazy an interference source is picked up by the F75.
Now how do you get the F75 stable ?
1. Select DE mode AND disc between 5 and 19. Sensitivity as high as possible without falsing.
Next problems seems to be chatter from the ground.
1. Make sure with the steps above that your ground noise is not interference.
2. GB the detector using fast-grab.
3. Go to manual GB and set the number that fast grab found 1 to 3 numbers to the positive side. So if fast grab was 60 set the manual GB to 61 to 63. That way the detector will have a positive GB offset and not give a signal to smallest changes in the ground.
A cellphone, even on standby, is a huge interference source !!!! Turn it off !!!
Last week i a got a call from Ralph at Sun Ray Electronics, who brought other good information to my attention about the F75 and chattering.
I have to say that i never used notch on the F75 before (just disc) but after playing with notch and disc i was able to reproduce what Ralph talked about.
Here is some examples what can happen if you use notch and disc:
1. If you set DISC to 0 and use Notch to cancel out target group 1 to 7 you still have accepted 0 and that causes the detector to be unstable.
2. If you have DISC set anywhere from 1 to 7 and up and you go to notch and select any number from 1 to 7 you have NOT notched out the numbers, you have notched them back in (accepted them), because Notch does the opposite from the current disc setting. That will cause the detector to be unstable again, because accepted numbers from 0 to 5 run a higher preamp gain.
3. If you think you have messed up your Disc/Notch settings do a factory reset by turning the detector off and then push the trigger forward and press menu button while turning the detector back on.
I hope that will help some guys not to have to send the detector in for repair for something that is not broken.
Thanks Ralph for the input,
F75 FAQ's :
Q 1. : Why is only one rubber washer for the lower stem in the box ? Is one missing ?
A: The F75 comes with only one rubber washer, because that's all you need. If you feel you need a second one contact the factory at: 915-225-0333
I bet they will be happy to send you a second one.
Q 2. What are the best settings to start with ?
A: When you start the F75 up the first time it starts in DE processing, Disc at 10 and sensitivity at 60. I found it to be a perfect setup to start with. Before you change anything make sure you get a feel for the detector with the above settings.
Q 3. After I ground balanced the detector with fastgrab it can't find a coin on the surface. Why is that ?
A: Make sure you don't see the words " can't GB" on the display while pumping the coil up and down over the ground.If that happens the detectors performance is close to zero after you release the trigger.
Q 4. The detector seems to pick up ground noice after ground balancing with fastgrab. What is wrong ?
A: When using fast-grab the detectors seems to be right on with the ground balance. It is so good that after ground balancing every tiny change in the ground matrix is seen as a target. I use fast-grab first and then change to manual ground balance and GB the detector plus 3 numbers. So if fastgrab was 70 I set it to 73 (positive offset). That way the detector doesn't see very small changes in the ground matrix as a target anymore. 3 numbers plus is about what a 1/8 turn on a 4 turn tesoro ground balance would be.
Q 5. I can't find the warranty card in the box of the F75. How can i make sure i get warranty service ?
A: Just keep you receipt from the dealer who sold it to you. You have 5 years warranty from the day you bought it. I taped the receipt in the F75 box to make sure it won't get lost.
Q 6. What are the hottest setting for the F75 ?
A: What sensitivity and modes can be used are controlled by the ground conditions and location (interference free or not).
I always start in the DE mode, Disc 10, sensitivity 50.
If you can push sensitivity high in that mode, it is an indication that you may be able to use the JE mode. But before you switch over to the JE mode make sure to lower the sensitivity. Because you can run sensitivity at 90 in DE mode doesn't mean you can run that same sensitivity in JE mode. On the other hand sensitivity at 60 in JE mode can be deeper than sens at 90 in DE mode. Some locations may not allow to use JE mode but DE mode could work just fine.
The target is to run as much sensitivity as possible while remain a very stable detector. That balance changes with ground condition and location.
Q 7. I can't get the F75 to work at the beach. Do you have some beach settings ?
A: First you need to know that most beaches ground balance under 40. That means you can NOT use fastgrab. You have to use manual GB to balance to ground under 40.
To avoid reflections from the salt use the DE mode and lower the sensitivity (Not JE mode because the gain is to high for salty ground).
Q 8. Even in DE mode the F75 is very unstable and noisy. Why is that ?
A: If you set the Disc lower than 5 or higher than 19 the detector runs at a higher gain in DE processing. That higher gain means more depth in interference free and mild ground areas but if interference or bad ground is present the detector becomes noisy and unstable.
For best stability run disc between 5 and 19 in DE mode. Reduce sensitivity too if needed.
The JE processing mode has a much higher preamp gain than the DE mode and is very sensitive to interference sources like cellphones, lightbulbs, power lines. If the detector goes crazy in that mode go back to DE mode and set Disc between 5 and 19.
I have a german homepage where i rate detectors by my own rating system.
People seem just to talk about depth, but that isn't the only strength a detector can have.
My 100 points system (10 max. for each category):
2. Depth and stability
3. Discrimination und Notchsystem
4. Ease of use
5. Types of hunting that can be done with the detector
6. Weight and balance
7. Powerconsumption and operating costs
8. Build Quality
10. Price and value
Now let me rate the F75:
Notch system, backlight, VDI display, Fastgrab GB, Magnetic Mineralization Bar Graph Read Out, Batterie meter, Depth on the fly meter, different Tone ids , True all metal mode, Processing modes, Confidence meter, Pinpoint, 11"DD coil.
It has not as much features as the DFX or Explorer, but it has enough.
I would rate it 8 points.
2. Depth and stability
You guys know my tests on the US nickel. For a single frequency detector depth is a 10 and stability is 10 too. Now some may say why 10 points on stability since the F75 gets unstable some times ? I see that this way. If you would the F75 set up to do as good as other single frequncy detector it would be as stable as any other detector. Just if you push it to depth other detectors can't reach anymore it can become unstable.
Points 10 here.
3. Disc and notch a 10 too. Once you understand the notch it is very easy to use and can be reversed. The disc works very well too, disc out large steel is not a problem.
4. Ease of use.
The menu system for a detector with all these features is very easy to use and see. If you have owned an Explorer or DFX you know what a 5 points detector is. This is a 10.
5. Types of hunting that can be done with the detector
Relic, coins, gold prospecting and due to the DD coil saltwater beaches well too for a single frequency detector. I have not rated a detector 10 points since no detector can do it all perfect. I rate this one 9 points because it can do most (Relics, Coins) very well and other things well (Gold Prospecting, Beaches).
6. Weight and balance
I don't know any other detector with a display that is so light-weight and well balanced.
7. Powerconsumption and operating costs
Using 4 AA bateries is the future, because you can buy a charger that drops operating costs so low, that you really make money detecting and not spend the found change to buy batteries. A runtime of over 30 hours with 4 AAs is the best.
8. Build Quality
An aluminum control box would push it to 10 but i'll rate it a 9 the way it is now.
Not lifetime, not only two years, it's five years.
10. Price and value
It is expensive but for some worth 940 $ internet price. After all the detectors i have bought and what they did for the money i would put this one in the $ 750 range. At that price it would sell like hotcakes because it would beat all is that pricerange. On the other hand i have the money to buy an over $ 1000 Explorer or DFX but i use the F75 as my number one right now. I just like the power on low conductors, the speed and the lack of weight.
Total points: 92 points
That is the highest total rating I gave to a detector to this day.
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.
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.
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'.
.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!
Some valuable observations this morning:
The ‘je’ mode has been trumped by the ‘bp’ mode. In dry sand (at a local
beach), I’m finding virtually identical Sens/depth characteristics on small &
very small targets that range the spectrum of conductivity…..noting the edge on
lower conductive items. I’m not sure I see any need for the ‘je’ mode anymore.
The ‘bp’ mode presents a greater audible intelligibility factor that is more
‘human friendly’…..and also appears to have a slightly greater depth ad. Yes, a
slightly slower sweep speed necessitates; however, the intuitiveness is
autonomous. The ‘je’ mode clocks faster, requiring the operator to pay extra
attention. (((Will see if I can send you guys a photo or two))).
Another observation is an observed 1” nominal greater depth performance on
dime-sized targets that range the entire spectrum of conductivity…..in a dry
sand beach environment. Once again, lower conductive targets having a slight ad
by an additional two-tenths (0.2”) of an inch over their higher conductive
On the beach…..where minimal EMI exists, I’m air-testing a nickel @3” greater
range…. and a dime @ approx 2.2” greater range in ‘bp’ mode vs. the standard F75
modes. I believe these numbers would increase…. if yet another increment of EMI
reduction were encountered (dictated by surrounding environment). A
tempest-booth test is in order……access permitting.
I am still cumulatively encountering a measured greater overall ID accuracy……
even in mild masking scenarios. ………..Thus far, I have zero need for ‘je’
mode….and zero need for older Gen F75.
Can you increase (slightly) the overall diameter of the pistol-grip? And can you
increase the pistol-grip foam density by approx 20%? Batteries appear to be
captivated markedly better. Is the control head a bit more water-resistant vs.
1st Gen F75’s?
Add’l testing in-prog. Will advise.
Spent 13 hours (on Sunday) with Ltd at 3 different/independent sites. Lessons
1st site = This is a antebellum home with slow sink-rate dirt that is moderately
nail infested. EMI was fairly high.....considering I could audibly hear the
transformer humming on the utility pole approx 45-feet away. The lesson learned
here is: If/when conditions warrant a reduction in Sens and a increase in Disc
to mitigate EMI.......the add'l advantages of the Ltd are then rendered useless.
This is also to say; If a older Gen F75 required a reduction in performance
settings due to local EMI conditions; subsequently, the new Ltd will require the
SAME performance reduction in order to ascertain the SAME stability. The
performance of the Ltd at this particular site would be/is the same exact
performance that would normally be achievable with the old Gen F75. Net gain =
.....Where EMI is fairly minimal, the Ltd is unsurpassed.
2nd site = This is a dozed/turned railroad spur/station. A absolute nightmare
due to the volume of trash.....would be similar/aka to a car junk-yard. This is
where I decided to reduce Sens to '80' and increase Disc to '6' w/tone options.
All things considered, the Ltd was a stupendous performer in this type of
environ. Other detectorists (of whom accompanied) were using other types of
detectors so as to reduce detector-to-detector interference. In short order,
they borrowed/acquired my back-up F75's.....switched to different Freq's and
also achieved very good success. The Ltd was exceptionally stable......and found
many items of significance......in what would....otherwise.....be a detector
3rd site = Second Seminole Indian War (1834 - 1836) site. Many (learning curve)
valuable lessons acquired here. This area is high in iron trash. The last 4
times that I hunted here with the original F75........yielded no more (zero)
non-ferrous items. On the orig F75.... Disc '1', Sens '99', PF, GB '90' & 4-tone
were my settings. This became important.....as with the Ltd, I placed all
settings to exactly the same.....with one exception; Disc on the Ltd would be at
'6' (and of course 'bp' mode). NO JOY. No non-ferrous targets located.
Eventually I would (incrementally) start lowering Disc......detecting for approx
10 minutes in each lower increment. No non-ferrous targets surfaced (yet).
NOTHING happened....UNTIL I finally hit a Disc setting of '1'. NOW my Ltd
settings finally matched the settings that I previously hunted with old Gen
F75....(except the Ltd has always been in 'bp' mode). Seven non-ferrous targets
surfaced in a 30' x 30' area.
Now..... hunting this exact same 30' x 30' area again..... but with Disc on
'0'..... the ground lit up with 91 more non-ferrous targets.
Lesson learned here: If an area has already been hunted/sanitized with older Gen
F75..... new targets can be located with new unit... AS LONG AS settings match
OR EXCEED the old F75 hunted settings (with the Ltd in new 'bp' mode)....with
one major difference (attribute); -- Of all 91 non-Fe targets recovered....I
lowered Sens to differing levels.....and nearly never lost a target at a
'reasonably' lower Sens setting; suffice to say; Disc MUST remain on '0' (in my
case...due to prev F75 hunted-out scenario). This is to say; there is Disc
dependency.....but certainly not much Sens requirement.
I am continuing to find higher ID resolution at depth. I have noticed zero
difference in battery consumption......and am continuing to notice the 'bp' mode
trumping the 'je' mode....especially in relic hunting applications.
I need to revise a previous statement; depth gain of this new 'bp' unit is
approx 0.2" on a dime in my dirt.....but in the real world, there is a marked
depth gain on very small targets; tiny buttons...air-rifle BB's etc........
In only 3 lengthy hunts; It is easy for me to conclude the new software tools
are a major attribute. Reverse the depth gauge...and this one is a substantial
Tom There is a substantial differential between je vs bp. The clock-speed/timing of bp is dramatically different from je. It's actually comparing apples to oranges. Soooo......this is to say; je is more EMI susceptible vs the bp mode. Disc for either mode is quite important for depth/Sens/performance. So far......BOTH mono & Disc '6' and 4-tone w/Disc '0' in the bp mode is quite a jump in performance vs the older modes. I am finding myself running Disc '0' & 4-tone much more often.......vs....Disc '6' & monotone. I think my 'fatigue' factor is becoming more tolerant.
Glad you loved the video. Another one is 'in the making'. As far as maximizing your F75 at a site that has been hit hard...... the principle is still the same. IF IF you can set Disc at '0', 4-tone, Sens '99' and hit it hard.....this is your best bet. If EMI is an issue....start by doing a Freq change with F1 thru F7. Find the freq that provides the least EMI. THEN.....if EMI is still a problem..... try raising Disc up to '4'. If EMI is still an issue....raise Disc to '5'. Then to Disc '6' if required. And with Disc '6'.....if EMI is still an issue...start lowering Sens. Try NOT to do any of these things.....if possible. It is good to have 'some' EMI. Then place coil on the ground and start sweeping. Quite a bit of EMI will 'go away'. PUSH YOUR LIMITS!!!
ON A DIFFERENT NOTE; This 'interactive' approach of the new Ltd prototype and the public.....appears to be a very good thing. Plus........you guys will know how to set up the new Ltd.....by the time it hits the streets.
This weekend, I performed extensive testing of the CL mode.....and at a few different locations. Conclusions/Summation:
The "CL" mode is only for medium-trash content (preferably less) areas. This is to say.... it is useless in very trashy environments. The clock-speed/recovery between targets is too slow..... and rightfully so.
In areas that are somewhat low in targets/trash, the "CL" mode is deeper. Exact depth gains vary.....as to be expected......depending upon conductivity & size of object. The "CL" mode has a stronger affinity for larger targets....... lending a greater depth gain (vs. any other mode). You must be warned.....the audio report is quite a bit delayed (very noticeable)...... from when the coil passes over the target vs. when the audio report is heard. In MY soil..... deeper targets were better detected with the coil scrubbing the ground. Other types of soils..... and the electronics my perform better with a few inchs air-gap above the ground.
I did manage to find some highly desirable relics in the 'CL' mode..... that the 'BP' mode would only produce a audible 'tick' for a response. I can confirm the 'CL'mode is deeper on certain targets. Two of the targets were .69cal musket balls (circa 1851).
What's interesting is; Whilst hunting in 'BP' mode ...... and locating 'fringe depth' targets......,,,,,, then switching back to standard/old F75 modes (pf/de/je).... and these "BP"-fringe targets would then produce only a short duration audio 'tick' of a report. SAME EXACT THING with certain "CL"-fringe targets........then switching from CL back to BP....and a audible 'tick' of a report would ensue. (((Switching from CL to pf/de/je modes..... and these "CL"-fringe targets were complely undetectable))).
There may need to be a line-in-the-sand drawn for a unit-of-measure large "TEST-STANDARD" target to be selected.....for a standardization of gauging/measuring depth-gain performance of CL mode vs. any/all other modes. A .69cal musket ball or .58cal Minie Ball may be a good start.......... but I believe the test-standard may need to be slightly larger.
I will say this.... as I did confirm this thought in the real world; A small cuff-button at fringe depth ...could be just as easily detected in CL mode vs. BP mode. No gain/loss in depth with a fairly small target in CL vs. BP. Now....PF/JE/DE modes....and the audio response on this exact target was just a audible 'tick'.
DE/PF/JE modes are for highly trashy areas.
BP mode is for fairly trashy areas.
CL mode is for moderate/low trash areas.
Plenty more testing to perform!
I have been remiss on providing certain info. After a hard-core detecting reiteration/experience.... I have positively verified serious performance gains with low EMI vs. extremely low EMI...... and this is in the real world. I have witnessed/experienced/verified this with the T2 several years ago.... then with the original F75...... and now with the Ltd. This should seem/be 'common sense'... but well worth a write.
Several weeks ago, I reported finding 141 more non-ferrous targets in a ...beat-to-death.... small area with the new Ltd. ,,,,,,, I went to the exact same spot a few days ago to try one additional experiment with the new Ltd. The last time I hunted there...and found 141 more non-ferrous targets...... I could run the Ltd wide-open w/Sens on '99', Disc '0', 'bp' & 4-tone. There existed a moderate amount of EMI when the coil was stationary...and not flat/parallel to the ground. Whilst sweeping the coil on the ground......the EMI went away.... and 141 non-ferrous targets were located. NOW...............fast-forward to just a few days ago. Exact same spot. I set up the detector to try the 'cl' mode......and noticed that NO EMI was present. Immediately, I switched over to 'bp' mode..... and STILL no audible EMI. . . . . and this is w/Sens on '99', Disc '0', 'bp', 4-tone.....everything max'ed out.......AND,,,,THIS IS WITH THE COIL IN THE AIR AND STATIONARY. Because of this.... I decided to cancel my intent to try 'cl' mode .... at least for a while...... and hunt in 'bp' mode. Something seemed wrong with the detector....as if Sens was nearly zero....and the unit was operating at a severely reduced performance capacity......due to such low EMI. Sweeping the coil.....and in the exact direction/footprints as from when I had located 141 more non-ferrous targets......and my suspicions would instantly be invalidated..... as I found ANOTHER 92 more non-ferrous targets..... in this exact same location. Low EMI vs. near-zero EMI made a tremendous difference. Percussion caps were detected down to 12". I've never seen this type of performance before.
It's in the finite details.
Tom Incomplete test results as follows:
Test standard (the target): A U.S. $1 Type-1 Gold Coin (1849 - 1853).
Florida inert dirt.
Since gold produces no halo.....no dirt-time required.
Buried 8" deep. Settings: Sens '90', G.B. '90', 4-tones & DISC '5'
pf/de = 8"
bp = 8" + 2.1"airgap
cl = 8" + 4.0"airgap
Buried 8" deep. Settings: Sens '90', G.B. '90', 4-tones & DISC '4'
pf/de = 8" + 0.1"airgap
bp = 8" + 3.5"airgap
cl = 8" + 4.5"airgap
Buried 8" deep. Settings: Sens '90', G.B. '90', 4-tones & DISC '0'
pf/de = 8" + 1.2"airgap
bp = 8" + 3.7"airgap
cl = 8" + 4.8"airgap
Buried 8" deep. Settings: SENS '99', G.B. '90', 4-tones & DISC '5'
pf/de = 8" + 0.3"airgap
bp = 8" + 2.4"airgap
cl = 8' + 4.2"airgap
BURIED 9" deep. Settings: SENS '90', G.B. '90', 4-tones & DISC '5'
pf/de = no joy
bp = 9" + 0"
cl = 9" + 2.1"airgap
Buried 9" deep. Settings: Sens '90', G.B. '90', 4-tones & DISC '4'
pf/de = no joy
bp = 9" + 0.6"airgap
cl = 9" + 2.7"airgap
Buried 9" deep. Settings: Sens '90', G.B. '90', 4-tones & DISC '0'
pf/de = no joy
bp = 9" + 0.8"airgap
cl = 9" + 3.0"airgap
---------------END OF STATUS THUS FAR-----------------
I wanted to boost Sens to '99' for the last set of tests......but EMI became an issue. The data above is fairly concrete; however, any time that Disc was dropped below '5'....... ""some"" EMI would ensue. This will reduce performance. EMI is one of the variables that I attempted to mitigate....attempt to make it a constant.
The two largest performance gains are when Disc is dropped below '5'....and when any one of the new modes were selected (ie dp or cl). WORD OF CAUTION, , , The 'cl' mode data above looks very impressive......... IS very impressive; HOWEVER, REMEMBER.....this mode can only be utilized in low trash-content areas.
IF IF IF..... I ever find time & location where EMI is near zero, I will bury the one-dollar gold coin at 10" deep and invoke Disc '0'.... and see/report the results. I predict the results will be stupendous.
All of the results above are MUCH more pronounced/impressive in EMI-free air-tests. This very small gold coin is a medium-size target in the pf/de mode. Once 'bp' or 'cl' mode is invoked....the U.S. $1 gold coin is viewed by the detector as a large coin.
Of note: Whilst performing the above tests..... the audio response whilst in pf/de mode were very short audio reports..... almost as short as a mid-tone click/tick. Whilst in 'bp' or 'cl' modes....the audio length reports were normal/full length audio responses.
For some folks; the data provided above may appear to be 'only moderate gains' whilst comparing 1st Gen F75 to the new Ltd; however, in real-world usage... the above results equate to tremendous improvements/success.
It is my STRONGEST recommendation that any serious relic hunter of whom owns a Ltd... should acquire a TYPE-1 U.S. $1.00 gold coin.... and preferably NOT a 1853..... as this was the most counterfeited (by China & Soviets) year coin. This coin is the most perfect representation of a test-standard for the T2/F75/Ltd due to it's size AND conductivity. Yes, a tiny (Size 2) 10Kt WHITE gold baby ring could suffice....... but a 'standard' needs to prevail.
Another hard-bought head-to-head comparison utilizing TYPE-1 U.S. one dollar gold coin:
'bp' mode/Sens '87'/Disc '5' is ~equiv~ to 'pf' mode/Sens '99'/Disc '0'.
There is a "World-Class" difference if you change 'bp' mode/Sens '87'... Disc to '4'. (((And obviously greater performance if you lower Disc even more....and/or raise Sens to higher settings))).
THE EDUCATION IS: IF YOU CAN TOLERATE A BIT MORE IRON AUDIO RESPONSES.....LOWER YOUR DISC!
I have made a VERY concerted effort recently with the LTD ...to hunt BEHIND a standard F75 at 11 different locations (and 11 different days) in a COIN HUNTING 'focus' (capacity) only. More specifically.....for lunch money at old schools. Lunch money IS nickels. In 1930.....school lunches were 5-Cents. You lose your nickel.....you lost your lunch! These 11 sites were old schools.....of where I have found voluminous amounts of early Buff's and 'V' nickels. The low conductivity of nickels is very important to the F75/LTD.
Results (compared to standard F75): NO JOY.
Summation: IF you are a coin hunter ONLY...........and you are contemplating upgrading from a standard F75 ... to the LTD......it is not necessary. HOWEVER, if you are a relic hunter.....the LTD is a tremendous boost over a standard F75. There is a HUGE difference on smaller low-conductor targets with the LTD. The TYPE-1 U.S. $1 gold dollar coin is still the bench/standard......and with stunning differential/delta.
In a natural setting.....the F75 LTD would acquire a nickel to depths just barely over 12". A standard F75 would be right at 12". YES......definately......IRT a larger air-gap w/LTD is there/available/advantageous. You can have a several-inch air-gap and still acquire a 11" deep nickel with the LTD. Not so with the standard F75. And Yes......the LTD is MUCH hotter on conductors that are lower than nickels.....such as thin/small womens gold rings (usually adorning stones). A thin wire-band 10Kt white-gold size 4 ring at 10" may not be detectable to many detectors........but the LTD in boost process will slam out a audio response on this target.....and with a several-inch air-gap. TRY IT! Make sure you test your other units on this same target.
The LTD in the new 'bp' mode .....is QUITE a bit hotter on small gold....vs....the 'je' mode. Time-and-time again......I keep testing/proving the 'bp' mode OVER the 'je' mode; so much so......that I have NO NEED for the 'je' mode any more................making any setting in the boost mode(s) ... transferable to the 'je' mode.... a moot point.
A topic well worth revisiting. F1 - F7 EMI mitigation. I know I have touched on this topic before......but now, I have much more amplifying information. I know I should utilize a U.S. $1 Type-1 gold coin.....as this is the perfect resonance (pinnacle performance) of the F75/LTD......yet, I used a common clad dime for better audience understanding.
Taking a U.S. clad dime to a area that presents near perfect conditions for testing. Here is the importance of Freq Shift (F1 - F7) .... so as to achieve maximum performance. At a local park, , , burying the dime @12"......in sanatized dirt........and virtually no EMI presence......the F75 will (just barely) detect this dime. Changing the frequency from F1 through F7........no EMI change of status (no audible EMI present on any channel).......... and also no change in performance of 12" dime detection with F75 LTD. The CZ-3D will also detect this dime with zero problems.
Moving 75-feet away from this location......where EMI is "moderate"......and a huge (and measureable) delta occurs. With the dime buried at only 8"...... a dramatic incursion ensued. Selecting the BEST frequency that provides the least EMI......and this dime can be detected with ease......AND this is to include over half-a-foot of air-gap over the ground. Yes.....this is to say that the coil is 6"-plus inches above the ground PLUS the 8" that the dime is buried. A total of 14"-plus inches between coil and dime.
Now........Selecting a different frequency that provides/presents a noticable amount of EMI (and this is NOT the worst channel/freq selection; rather, a 'middle-of-the-road' selection).......and the detection of this 8" dime is COMPLETELY undetectable. Here...........The CZ-3D still poses extreme audible stability.........absolutely no idea there is any form of EMI what-so-ever....BUT, BUT, BUT......the CZ will only detect this dime to 10". This is categorized as the most dangerous type of (electronic related) hunting......because the operator has ABSOLUTELY NO IDEA the unit is operating at a reduced performance level. Unsuspected and undetected/unknowing reduced performance. The operator would NEVER know it; subsequently, never suspect any form of performance reduction.
THE BEST WAY TO REDUCE EMI: Place F75 in all-metal mode with max Sens ('99'). Hold coil about a foot above the ground.....very still......and perfectly parallel with the ground. Select F1 through F7.........one at a time...... and listen to each channel/freq for about 4-5 seconds. Find the one freq/channel that provides the least interference. Now you can switch back over to the ID mode......and.....yes......this Freq/channel selection will stay the same whilst switching over to the ID mode. If you are running the unit 'wide open'....and you still are encountering EMI..... you can change Disc to a setting of '5'. There is a huge difference between Disc '4'....and Disc '5'. You should not have to increase Disc to higher numbers. If EMI is still present.... you now can start to drop Sens .... until EMI is gone. Remember; you are already on the best possible F1 through F7 Freq/channel selection...and must employ other methods so as to reduce EMI... if it is still present.
If you look at your LCD depth bar-graph......and EMI is causing it to jump all the way into the middle bar-graph (medium strength signal) ............you will only be able to detect targets that are (at least) as strong/powerful.....OR STRONGER (shallower) as that middle bar-graph. This is also to say that......if you want to get rid of audible EMI......you would then be required to reduce Sensitivity to the point where targets in that middle bar-graph (and deeper targets)... would no longer be detected. What you are doing is.....reducing the sensitivity of the detector to 'just below' the signal strength of the EMI. Said differently; If EMI is so strong......that this specific EMI "looks like" a 7" deep target................then the detector will only be capable of detecting targets up to 7" deep....and no deeper... in this hunting area.
Some of the best days to hunt.....as far as EMI is concerned......is at the very end of a hard rain........or shortly after a hard rain......as this is what washes the salts off of nearby powerlines.
If you are 'beating' an old/hunted-out area again.......and you suddenly learn that you are finding a lot more targets........it may very well be that you are encountering less EMI on this specific day.
I can only stress the level of importance of EMI mitigation. USE THAT F1 THROUGH F7 OPTION.
First and foremost; The F75 LTD/Special Edition still remains the flagship; per expectations. Yes, this is comparing a $700 G2 to a $1200 F75 LTD. This is to say, the G2 will not hunt behind the $1200 F75 LTD. The G2 does not employ a boost (boost process 'bp') mode. HOWEVER, there are major attributes of the G2:
Several years ago the MXT was THE industry lead/standard for iron handling capabilities. Then..... the Teknetics Omega. And now.....the G2 is the trump card. At extremely iron/nail rich environments, the G2 was exceptionally quiet. The G2 poses hair-splitting Iron Disc.....and Iron ID. Unlike the T2, F75 and Omega with Iron Disc of '21', '6' and '16' respectively........for best unmasking in iron; the G2 poses a somewhat different requirement. It is much more sensitive to site-specific iron decay/decomposition status. Some areas require a Disc setting of '26' for heavily decomposed iron.....for best iron see-through/unmasking. Other areas may require a Disc setting up to '29' .... for less decomposed iron. The area in which you hunt will quickly teach you......and dictate the decay status of the iron. The intent is to 'just barely' Disc out the small iron.
The G2 is a hybrid 19-Khz Omega.....and shares similar attributes with the T2. The unit has very few controls, making it a very easy detector to learn/operate. The 11" elliptical DD coil on the G2 is the nominal ideal coil for relic hunting applications.
In a 'medium' EMI environment.....the G2 never once alluded to EMI presence......and this is with the Sens wide open; on '100'.
Due to the narrow electromagnetic footprint of the 11" DD coil.... as to be expected..... the G2 generates extremely enhanced adjacent target separation characteristics; subsequently, making any comparison of this unit to any other unit without a DD coil... a unfair null/void comparison. Extremely tight EM footprint coils are far superior to concentric coils in trashy environments; necessarily, most of the areas we like to hunt.
Hunting relic sites where relics are fairly deep and partially masked.... the F75 LTD prevails. Areas where good targets are fairly shallow and partially masked, the G2 will run neck-and-neck with the F75 LTD....with one measureable G2 attribute; that being 'more stable/quiet' in iron infested areas. Yes, there is a slight 'detectability' advantage with the G2...to lower conductors.....in the 'foil' range.
The G2 multi-segment signal strength bar graph is much more useful than the 'segment-limited' depth gauge on the F75.
On a 11-hour controlled/structured real-world hunt..... I could only locate just a few non-ferrous items (in 11-hours).... hunting behind a F75 LTD. The specific hunted areas are the ones mentioned previously in this long thread; hence, my deliberate intent of posting this G2 field-test performance report in this thread. --- Keep in mind, the G2 is a dedicated prospecting unit....that can secondarily function in the capacity of a relic hunter. Since I do not prospect, I will not be able to report performance of this units design intent.
Power supply = A single battery. This configuration is superior. Less associated parts and wiring in the detector (less failures). With many other detectors of various brands that require multiple batteries,,,, I have encountered 'single' battery failure....causing the multi-pack to become rendered useless....with the one bad battery; subsequently requiring the entire set of batteries to be changed out. I do not carry a DVM in the field.... to find out which specific battery failed.
Overall.............the G2's lack of 'field fatigue' factor stands out the most. I know the unit is more sensitive to smaller/lower conductors ... vs ... the F75 LTD; so..............a micro-jewelry hunt in dry sand is in order. This will include wet salt performance test. I suspect it will do very well with small gold and tiny gold..............but will not trump the 20-year old 71-Khz Gold Bug 2 in a micro-gold environ/capacity.