F75se, etrac, CTX, V3i in ground target comparison

Was at the church next to my house last nite using the CTX running combined mode, auto sensitivity, fast on, deep off, when I came upon this signal reading 12-34/35, with the depth showing 9 inches. It was only a 2 way hit. I had dug a nice merc dime close to this spot a year ago. I'm thinking maybe IH.
So, since this was next to my house I figured what better target to do some detector comparisons as the 4 flagships are hard to get in my rice burner p/u at one time when I'm detecting away from my house. Anyway, I got the V3i out first and to no avail could I get a signal. It was getting late so I marked the target using the CTX with intentions of further looking at this target in the early A.M. It's 4:05 CDST now and I'm back on the target. First up was again the CTX. I turned it on while over the target in auto sensivity, fast on deep off, in combined mode. The CTX when turned on was reasding 19 sens in auto. I then started sweeping the target from the only direction I got the signal from last nite. I got no signal, I continued to sweep and when the CTX hit 23 sens in auto I started getting a tone. The CTX continued to keep going up and reached 27. During the time from 23 to 27 I got good consistent sweet clean tone in this one spot. It was again showing 9 inches. During pinpoint it showed 8 inches. I went to manual sensivity and could get the target only at 21 and higher. When sweeping from other directions I could sometimes get a small squeal-not something to make me dig or even make me further investigate maybe by turning-sounded more like a mini false.

Next up was the etrac with sunray x-5 coil. Nothing in auto sensivity, so tried manual 27-30. At 30 I got extremely short squeal-a sound that told me nothing, I would not have investigated-again sounded like a mini false. Next was a different etrac with the 13" ultimate coil. In auto sens the etrac went to 25 and I got a thunking sound with the cursor skipping all around the screen. And that is with fast on/off, deep on/off. All possible combinations again no change. Going into manual sensivity at 27 I got tone. Ferrous numbers were all over the place from 01-27 with a conductive numbers of 36-40. I did perform a noise cancel with sensivity changes. I would have dug this target based on the signal. The audio was not the greatest with some sweeps giving better quality tone than others and the same goes with the numbers, some sweeps gave better numbers. Using the same etrac with coil change to 10x12 sef. The 10x12 sef in auto sensivity at 25 gave a tonking noise with cursor jumping all over the place. I couldn't make heads or tails of what I was looking at. At 25 manual I got a signal not the best, so I went to 27 man sensitivity. I got tone with ferous numbers again jumping from 01to 27 with conductive numbers coming in 36-40. I played with the deep on/off and fast on/off and the adjustments seemed to have no effect on signal quality or screen numbers. I would have dug this target based on my signals/screen numbers in manual sensivity at 27 and up. Next up, same etrac with the stock procoil. Doing a noise cancel first running in auto sensivity the sensivity went to 25. The target was not detected. Swept from all directions. Went to manual 25 still no joy. Played with deep off/on, recovery fast on/off, still no joy. Went to 27,28 still no joy. At manual sens settings of 29 and 30 all I got is a tonking with the cursor hop skip and jumping all over place. I saw no signal I would have dug using the stock procoil.

Next up was the fisher F75se with 7x11 DD coil. Did a fast grab ground balance number 60 came in the screen. I mitigated for EMI the best I could with freq offset. Started in BP mode 4T with sens 70 dis 4 and was hitting the target. It was only a 2 way hit from the same position I was hitting it with etrac/CTX. Was seeing numbers in the screen bouncing between 34 and 84. Went to disc 6 and could still hit the target but it was only now and then. Disc 7 was no joy. Tried discs 0, 1, 2, 3, 4, 5, 6, 7 at 70 sens. I got a signal in disc 0, but the audio was terrible, same with disc 1, disc 2 was slightly better, so was disc 3. Disc 4 seemed to provide the best audio. So in disc 4 I started varying sens. I could get the target as low as 60 sens. 70 sens actually sounded better 80. Remember there is EMI in the area according to the F75 se. I seemed to get better hits with a more brisk sweep-substantially faster than a sweep you usually use with a minelab etrac. The target was pinpointed and saying 9 inches. ps I don't have a lot of confidence in depth gauge on f75se. But it was what is was. Actual target after recovery read 52-54 with f75se on top of the ground.

Next up was the White's V3i . In hi pro mode in rx gain of 9 disc 85, filter 5 bp. I mitigated the EMI and was not getting any feedback while in pinpoint with coil at waist levle. Left ground tracking in auto and ground balanced with 0 offset. Using 3 freq with recovery delays of 50, 60, 70 ,80,90 I got no tone whatsoever on any sweep. And I varied my sweeps to a crawl to a more brisk sweep. Next I ground balanced with the following offsets: plus 1, plus 3, plus 5, plus 7, plus 9 and tried all the filters excepth 12.5s, still no joy. I then ground balanced with negative offsets of -1, -3, -5, -7 and again no joy. I tried both single freq 2.5 and 7.5 with above settings again no joy. Figuring EMI might be causing me not to get a tone I back my rx gain down to 6 and turned TX boost on. Again no joy. So I tried factory coin and jewelry with varied amounts of rx gain, dic settings,and recovery delay. Still no joy. So I tried some correlate programs I borrowed from a few gents who frequent forums. Finally I started getting a tone. Got a few readings of 54 -70 VDI. The only thing was I could only a get a tone with numbers about 1 out of every 4 sweeps. Going to pinpoint showed the target at 7 inches with 22.5 and 7.5 almost the same intensity with 7.5 being slightly higher and 2.5 lower than the 7.5 reading. My V3i airtest a quarter at around 13.5 inches and the coil does run rx gain 15 tx boost on, no overload. I don't think I would have ever found this particluar target with the V3i unless all of Jupiters moons had been aligned. I had hunted this spot/area with V3i 1.5 yrs ago and never detected this target.

I started digging the target and after a little dirt I would check for iron/misc with my garrett pinpointer. I kept a diggin, checking both the hole and the dirt pile on the towel. I got down about 6 inches and so far nothing, kept digging now getting almost to the depth of my pinpointer length I finally got a tone on my pinpointer. The target according to my pinpointer was off to the side slightly where I was digging. So now I proceeding slowly and could see the target embedded. I measured to the top of the embedded target and it was 1/4 inch longer than my pinpointer is long. So around 9.25 inches deep. The target was the base of a light bulb. Needless to say I was dissapointed. But I did get to do some good comparison testing. I would have loved to have dug more around the target to see just what other possible things were around the light bulb base, but I didn't want to dig excessively in the church yard. It is dry here and would look bad.



Edited 1 time(s). Last edit at 07/30/2012 02:10PM by tnsharpshooter.

Thanks tnsharpshooter for making the effort to post a very well-explained side-by-side comparison. From your description it would appear that the limiting factor to using higher sens levels on the F75se was EMI. There should be considerably more target signal 'boost' / depth if a higher sens could have been used.

As an owner of the original F75... I've often wondered about the depth benefit vs signal volume 'increase' of the 'boost process' over the regular DE mode using identical discrimination settings. For my prospecting applications the basic F75 performance... in both the all-metal motion and JE discriminate modes... is quite satisfactory in moderate-to-high magnetic susceptible iron mineralization for a VLF unit, but perhaps having a boost process mode would... in some areas... improve performance sufficiently to warrant the expense. I believe Tom has commented at length on this subject... as I recall he mentioned that 'sensitivity' was a more notable improvement vs any great depth improvement overall. But then perhaps I'm mistaken... Tom... any comment?

Thanks again tnsharpshooter... an excellent... informative post particularly for those hobbyists who do not own these units...

Jim.

Humble pie, you're quite welcome. You know I probably should have checked the target in DE mode. My testing took over 3 hours the way it was done. It wouldn't have took near as long if not for all the possible combo settings on the V3i. I wish too I had put the 5 inch coil on the F75se and gave it a go. I don't have a lot of experience with the f75se, but my knowledge level was significantly increased via Tom's post on the F75se. Something else I learned is even when the f75 is cutting up some while held above the ground it does settle down quite a bit when you start sweeping. Maybe I will get another in ground signal I find interesting and do some tests. It's time consuming yet it teaches me something everytime I do it.

Thanks for taking the time for this test.
It would have been nice to have a F75 LTD and try it in boost mode.

Markg, Correct me if I'm wrong, but aren't the f75ltd and f75se the same detector from a performance standpoint. I did, in fact, test the f75se.

tns.s. = It is in these painstaking efforts (albeit only one real target tested)....... that will substantially increase your finds (subsequently..... 'fun factor')...... by knowing WHICH detector to choose .... and HOW to set it up for max performance. Life is short. Do it right the first time...... with the best tools...... set up in the best possible set-up confguration........ for the limited amount of time you have to expend.

Jim. Correct. On half-dime (fish-scale) sized targets.... and larger......... the 'boost process' on the F75 merely enhances the audio volume..... with only a minute' increase in depth abilities. Yet............ with the boost process audio volume increase........... the 'human intelligibility' (audibly) increase ....certainly enhances dig/no-dig target recovery. A fringe depth target that would (otherwise) produce a click/tick audio duration length............ now............ (with boost process employed/invoked)..... becomes a nearly full-length audio report.

Now........... on targets that are smaller than a half-dime.................... especially if they are lower conductors.......... there is certainly a measurable depth increase whilst in boost process (vs a standard F75).

Using the 5" DD coil on the F75 SE whilst in 'boost process'..... exposes a tremendous boost in performance (both in depth & audio resolution).... over a standard F75.

If you are a 'coins only' hunter............ the additional 'boost process' mode is only a mild (at best) enhancement.

Sorry about that, I re-read his post and he does mention being in BP mode.
My oversight.


tnsharpshooter Wrote:
-------------------------------------------------------
> Markg, Correct me if I'm wrong, but aren't the
> f75ltd and f75se the same detector from a
> performance standpoint. I did, in fact, test the
> f75se.