? for Mike Hillis re: new F75 'FA mode' vs F19

[horikindaguy]

hi Mike, since you've been a tester for both the F19 and the 'new' version of F75 I wanted your opinion/comparison of these 2 new machines.
As a 'trashy' park hunter I'm wondering how the new 'FA mode' and Digital Shielding compare to the F19 (effectively the same as G2 minus some features).
I do think the F19 with the 5X10 coil has the advantage in 'ease of coverage' as it's a closed coil vs the F75 11" open coil. The 5" dd does come with the LTD but is too small/slow for my desired use (faster ground coverage yields more finds). also the new LTD's Boost Mode can't be combined with the FA Mode correct?
It seems the new 'FA mode' (along with the Digital Shielding) is an attempt to give the F75 some of the good manners that the F19/G2 already have.
As a G2 owner I'm wondering if the new F75 would be a worthwhile purchase (for urban park use). I really like my G2 but I'm always wishing I had another couple inches of depth with the solid VID capability and target separation the G2/F19's are noted for...some of the parks I detect are old and have the potential for some nice older coins/relics.

thanks....

 

[horikindaguy]

I should add that I originally purchased an F75 in April, 2007 with great hopes (upgrade from CZ). I sold it less than a year later due to excessive chattering and the 'hail mary' nature of digging deep signals with no good indication of whether they were even ferrous or non-ferrous. I moved to an FBS machine and was astonished at the number of 'keepers' found in exactly the same spots I had previously spent hours pounding with the F75.

I am thinking of possibly going 'full circle' based on (upcoming) positive reviews of the 'new' F75 SW or instead simply upgrading from my G2 to the F19 since there are a couple of new features there that would absolutely be useful....

cheers

 

[Mike Hillis]

Hi Horikindaguy,

I couldn't use a F75 in the past due to the nature and amount of the interfence at most of my sites. The new shielding allows me to run the F75 even at max sensitivity. I still have places where the interference causes some chatter but it's reduced in nature and is easier to listen to. It tones down the sparkiness of some of the other processes but Fisher is letting you turn this on or off as you need it. For me it really helps.

The FA (fast) process is a trash process. Works great in iron trash using the 2toned mode. Works great in alum trash for coin hunting. It will light up targets that the other process can't see or won't see well enough to stop you from walking over them. However, it is not a deep process. It will unmask very well but it is not the deepest process.

Bottom line for me, the new EMI filtering has put a F75 back into my hands. The FA process lights up more stuff in the ground.
_____________________________________________________________________

Regards the F19, I like the physical set of the G2 better, but I like the feature set of the F19 better than the G2.

_____________________________________________________________________

The FA process unmasked better than the G2. The G2 is still more stable than the F75 just because of the operating frequency benefits. But the new filter of the F75 means better depth just because you can hear deeper and fainter targets with a stable machine.

It may be that if the G2 is performing well for you all you need to add are some accessory coils so you can better match the coil to the site conditions.

HH
Mike

 

[horikindaguy]

thanks for the response Mike,

"The FA process unmasked better than the G2. The G2 is still more stable than the F75 just because of the operating frequency benefits. But the new filter of the F75 means better depth just because you can hear deeper and fainter targets with a stable machine."

you'd think the G2 would be more 'sparky' due to the higher freq (19K vs 13K) but their's obviously a lot more going on 'under the hood'. I'm hoping the audio/VID
info for the deeper faint targets will be good/unique enough to differentiate ferrous vs non-ferrous, i.e. less iron bits, etc. I wouldn't ask/need much more than that.

your comments make me lean towards the new F75 LTD. If I get one I'll buy the new 5x10 closed DD coil with it.

I'm looking forward to some reviews come November or so when folks actually have the new version 'in hand'. I'll be a spring/2015 buyer if the reviews 'ring in' well.

as a retired engineer (EE) I'm naturally cautious with changing/adding new machines, cheers and hoping for the best....

 

[liondogs]

Mike

You stated that the FA process is not a deep process. How did you come to that conclusion? Was it because you located a target using another process and the FA process would not see it?

 

[Mike Hillis]

Hi Joe,
Do you see it otherwise?

HH
Mike

 

[Mike Hillis]

My edit time elapes before i could save my changes....

Post should have looked like this......

Hi Joe,
You have different expectations?

Unmasking and Depth are at opposite ends of the spectrum. Depth requires a longer look. Unmasking requires a faster look. Can't get away from it. The FA process is so much faster than the other processes that it inherently has a depth restriction. This difference is expected and is easist to see in air tests.

In the ground, the FA process will respond to objects that the other processes do not respond to at all, or barely respond to due to target (and ground mineral) masking.

HH
Mike

 

[Keith Southern]

I find the FA mode to be fast audio yet not neccesarily faster Separation...

But Fast Audio is not required to unmask as much as the ability of the detector to report multiple targets at the same time intelligently ..This will unmask and also give you more depth in trash or iron....the FT machines using the ON/OFF type audio report cant get into the full audio blending ...they have to rely on shut down start up between the target's to perform 2 tone unmasking...

Once a target becomes so tightly intermingled say like a small 1 dollar gold piece with nails in and around it...All the speed in the world will not hear targets like this... the nails and the coin are in the same snapshot...This is where the 2 tone on the F75/T2 starts to falter...if the tone is not breaking till well above the nails while using 2 tone mode on a well hunted site then all the speed does not help...but a more precise way to set where the tone breaks can do miracles to same target...say a nail reads10 so break the tone from low to high at 11..that intermingled gold coin that did not have enough conductance to overpower the nails to get the tone to go above the factory setting tone break will now have alot better chance of reporting...

Speed is good but its not the final unmasker....

Speed helps isolate for more accurate target I.D. for VISUAL dig or not dig situtations

but if you are relying on tone to allow you to dig the user defined break will net more..

Add some ability to blend the tone instead of having one tone or the other only being able to report at time.. have the tone report be akin to a caliope ..minute changes can occur in the report and be noitced intelligently audio wise and couple that with exact tone breaks and more unmasking can take place...

In the real world hunts with thousands of nails with non ferrous targets intermingled like jambalya then advanced settings are needed..

Speed - separation is good over a slower unit in the ability to find more..

Speed-separation-exac tone disc break will find more than the others..

Decent Speed-separation-exact tone disc break- tone blendability will find even more..

things can go further with filtering of rejected targets and so forth...

Keith







Keith

 

[Mike Hillis]

Hi Keith,
I understand what you are saying about "tone blending". Currently Fisher doesn't offer anything like this on their digital platforms.

Right now, the F75/T2 digital platform gives us several methods to unmask:

First is the normal F75/T2 reporting/recovery speed (which isn't really normal),

Second are the various audio modes in combination with the preset iron discrimination setting as found with the 2F ( and the new 2H, 2L, and 1N audio modes),

Third is the various audio modes in combination with variable disc settings as found with the 1 and 1F audio modes. The T2 would naturally be more exact in this as it has a wider iron disc range.

Forth, and new, is that the design engineers performed something many thought impossible, and that was to squeeze even more speed out of the T2/F75 platform, which they did in the creation of the FA (Fast) process. The FA process is almost a 1/3rd faster than the normal processing speed. Just the additional speed of recovery alone is going to light up even more targets in the ground because there is still masking taking place at the normal processing speed. The key is, as you said, intelligibility. How to turn those new, additional target responses into something that makes you recover it.

The intelligibility is inherent in the preset iron disc settings as the non-ferrous tone stands out clearly against the low ferrous tone.
The intelligibility is inherent in the variable disc modes, too, because you either hear a response above the disc setting or you don't.

In the gold coin in nails example, a faster recovery speed is going to be better able to see the coin in the nails and report it as non-ferrous using both the preset and variable iron discrimination.

If the gold coin is lying in the nails in such a way as to be electrically connected to the nail, is it going to raise the conductivity of the attached nail and coin in such a way to report above the disc setting? If so, you are going to hear it using the variable iron disc setting. If the electrically attached coin and nail do not do anything to raise the response above the disc setting, even a blended audio is not going to bring it to your attention.

HH
Mike

 

[Keith Southern]

Thats why we can never get it all...

but we need advanced methods to get what is available to current VLF technology limits...

I could go on for hours about how things in iron are electrically connected yet ..

The most important thing is if First Texas wants to compete with other machines in unmasking at this date and time...the Two tone mode needs to be further developed..

The one tone mode on the 75 and t2 is the best unmasker for the platfrorm...yet for tight work the audio is not right...it becomes to noisy to decern fasle hits from legitimate hits when the iron is overwhelming on a site..



Keith

 

[Mike Hillis]

Keith,
One of the hardest things I find to deal with in a site with a lot of nails is that the durn thing reports differently based upon the angle of approach. If I sweep it perpendicular to the coil, I can disc it out at an expected setting. If I sweep with the nail horizontal it reports higher than my disc because it is falsing off one, or both of the ends. Never mind the nails bent at various angles, or the ones standing straight up and down.

So in a nail bed, most of what I am going to hear are going to be falses based upon nail orientation. Somehow in all those reports above my nail disc setting I have to pick out the true non-ferrous responses that are reporting above my disc setting but still down in the iron range because of their electrical connection to the co-located nails.

Just thinking out loud as this has no bearing on the new F75......But......Have you ever considered an iron audio arrangement where the iron range is multitone, much like the dp audio mode, except that only the iron range is affected. The ferrous range has a variable pitch from...say 600 hz to 250 hz based upon the ferrous TID number. Then a "above the disc" single tone that is a mixture of both ferrous tone and the non-ferrous tone for responses that are above the disc setting but still inside the ferrous range. The mix tone pitches are based upon the ferrous TID and the non-ferrous tone.

The end result would be intelligible iron audio below the disc setting (you know what your iron is below your disc range) an intelligible mixed audio for targets that respond above the disc setting but which are still inside the ferrous range (you can hear the iron above your disc range mixed in with the high non-ferrous tone) and a pure non-ferrous response for objects above the ferrous range.

HH
Mike

 

[Keith Southern]

N/T