Jump to content

F5 Vs F75 Or T2 All Metal


Recommended Posts

Give the F5 a good run, even take another machine with you to cross check. Be interesting how it does.

  • Like 2
Link to comment
Share on other sites


23 hours ago, Daniel Tn said:

Something I had forgotten about since last having an F75:  the newer DST model F75s have been neutered from what made them great.  They have a VERY weak all metal mode now.  To get a good one, you'll have to find one that hasn't been updated and is a non DST model.  Just an example for you...the F75 I recently traded for is a DST model. With it at 99 sensitivity, it will only AIR TEST a .58 cal Minie ball out to 9.5-10 inches in all metal.  And you have to really be listening to hear it. By comparison, we tested my buddys original non updated F75 on the same minie ball and his unit sounds like it has an audio boost enabled in all metal and is much more powerful.  We couldn't get his to 99 sens due to chatter but with it on 80, it was calm and could detect that minie out to 14 inches.  Yes, that's a 4 inch difference.  Whereas the newer one was weak and barely hearable at 10 inches...his was a "no doubt about it" signal at 10...very pronounced.  We could actually turn his sensitivity down to 60 and 70 and still get better distance than the neutered F75 at 99 sens.  I traded a CZ70 Pro with George here on the forum for a T2. I'm hoping like crazy that it's a non DST model lol. Or at least isn't as badly neutered as the F75 I have.  

Decided to check out my F75 Black (w/cache and boost processes) -- serial number 0517140086.  (I bought this new in late June 2017.  I forget if the year of manufacture, from the serial number, is the 3rd&4th digits or the 5th&6th digits.)

Caveat:  As I mentioned in a thread a couple weeks back about variations in specific detector units and potentially how uniform they are, air tests done by different people (differences in hearing levels) and with different test targets can lead to different results.  So keep than in mind when comparing my results with Daniel's.

I don't have any Civil War bullets but I do have one I think is late 19th Century and that's what I used for this test.  It is *not* shaped like a rocket nose cone as many CW bullets I've seen.  It is cylindrical with a spherical ('domed') tip.  The tip is a bit flattened and the striations along its length indicate it has been fired.  The diameter is 11.7 mm (0.46 in) and the current length (i.e. with flattened nose) is 20.6 mm (0.81 in).  It has two rings.  I'm not very knowledgeable regarding firearms, etc. but I think 0.46 inch diameter means "46 caliber".  Whether that was its size when manufactured or if my measurement is a bit larger now due to treatment and environmental factors, IDK.

I didn't use headphones since I was located down past the coil when swiping the bullet at distance.  I'm confident I was hearing (and eventually not hearing) the target for the numbers I post below, but they were rather quiet when I got to max distance.  I was operating in Motion All Metal mode.  I varied the sensitivity as well as turning DST on and off (see table below).  I swiped the bullet in two directions.  "Orientation 1 -- axis at coil" in the table below has the bullet oriented pointing at the coil.  For "Orientation 2 -- short side" I swiped the bullet with its axis perpendicular to the coil and in its short direction.  I didn't do any tests perpendicular to the coil sweeping in the bullet's long direction.

Here are the results:

F75_bullet_air-test.png.899643fb3f5f5f2063836676ce7d5dc7.png

The best performance was in fact with DST turned on, sensitivity maxed out.  But for the other gain values I didn't notice any difference in air 'depth' for lower values of gain between DST 'on' and DST 'off'.

Here are some thoughts which are quite speculative and maybe not very accurate, so keep that in mind:

1) My results were closer to Daniel's friend's original (pre-DST implementation) F75.  (I don't know how much the difference in target size plays into this comparison....)

2) I've never quite understood the F75 sensitivity.  According to Mike Hillis who is a huge proponent of the F75, it doesn't really work like many other detectors when adjusted.  Rather than to misquote him I'll leave it at that, but I think he reported that here on DetectorProspector.com at least once, but probably quite a while ago.  I've read the manual many times and still don't understand this setting.  According to the manual there is a significant shift going from 29 and below to 30 and above.

3) The manual does talk about Boost Process (a setting in discrimination mode) potentially affecting the All Metal side of the detector in a positive -- i.e. deeper -- manner!  But I had that set at DE ('default') process so shouldn't have affected my measurements.

4) Changing DST value off/on and vice versa requires a factory reset.  I got confused when this put me back in discrimination mode since normally upon turning the F75 off, all settings are saved.  When I forgot this reset effect and accidentally checked in discrim ('DE' process, sens = 80) the air 'depth' was considerably lower -- in the 9" range.

5) I recall there's been considerable discussion but also apparent uncertainty over the years as to what DST does and how it affects performance.  It's certainly possible (and I remind you this is pure speculation) that Fisher over the years has tweaked this in multiple ways and multiple times to try and improve performance.  I think my unit is one of the later ones, even among the DST models, so maybe the early ones with DST were 'neutered' and the later ones not-so-much??

P.S. To be clear, the distances in the table are the max distance for which I could still hear the target.  In the "axis at coil" case that was the approximate distance from the *nearest* part of the bullet (which was in fact the domed end) to the coil cover bottom surface.  Thus the other end of the bullet was about 0.8" further away.  And the uncertainties on these measurements are estimated between 1/4" and 1/2" in all cases.

P.P.S. I measured the bullet's specific gravity using the Archimedes submersion method to get the volume.  The result was 10.5-10.6 (range reflects scale precision).  Pure lead has an S.G. of 11.35 so my bullet is likely an alloy. (Were CW bullets pure lead?)  I report this as besides difference in bullet size and shape the composition could affect the air depth measurement.

  • Like 4
Link to comment
Share on other sites

While I haven't used a F75 it's cousin the T2 is a similar animal and I have two of them, a DST one and an old Greenie.

The old Greenie is much more unstable and ratty, but appears to have better depth.  The newer DST one runs really stable but doesn't have the same depth performance from what I've seen, regardless of DST settings.

I think more was done to make the detector run stable than just DST, perhaps as the T2 was famous for being so unstable and the improvements with the newer DST models certainly sorted that out.  It's party why I did the shielding paint on my old model T2 to try improve it's EMI handling which I felt it did help a bit.

I don't think it's sensitivity that has the weird stepping in it, it's the disc, my T2 is good on deep targets on something like 40 sensitivity, cranking it up in the 90's doesn't really change the depth all that much, maybe the higher sensitivity settings are more for tiny targets, I don't know it's been a long time since I've bothered using the T2 for prospecting and back when I did I was rather clueless.

On the T2 having the disc setting below 10 seems to have some sort of extra power, go above 10 and the power drops off, then again at disc 50 there is another sort of extra power kicking in, yes in these levels the detector is more unstable but also deeper.  Under 10 it can be rather ratty but at that point has the most depth, For the most depth I run at disc 0.  Running these disc numbers gives the All metal performance while having some disc involved.

Not sure how this translates over to the F75 but it's rather dramatic on the T2, the T2's iron range goes all the way up to about 40 though and you would think would be the better relic and gold prospecting machine because of this finer iron adjustment.

  • Like 1
Link to comment
Share on other sites

Not having a F75/T2, I only know what I have read in the Owners Manual & on Forum post.

My understanding is that there is a way to run Bp Boost process in both Disc mode and All Metal. I wonder if Daniel tried DST off and Bp on?

The Sensitivity control on these units are a combination of Gain & Threshold levels. The Anfibio is the same.

The Disc control does do more than just knock out targets. It also reduces EMI at modest levels, then opens the power back up at higher levels of applied Disc. My Anfibio is similar.

Lead bullets are always an alloy. Usually with Tin. Factory bullets are swaged, homemade are cast. 

  • Like 4
Link to comment
Share on other sites

  • The title was changed to F5 Vs F75 Or T2 All Metal

The F75 I have is just a standard one with DST.  It doesn't have boost or cache processes.  It is quiet in both 9.0 and 9.1 all the way to 99 sens.  The older F75s seem to have an amplified/boosted audio signal in all metal.  The hits are much more of a "thump". But you'd never get one of those to 99 sens without it going crazy.  Fortunately all you needed was 70-80 and that is better than what this newer one does at 99.  Minie balls are 1/2 oz lead, .577 in diameter.  They ring up between a round pull tab and zinc cent on most ID machines.  

I received a black T2 that I traded for today and just got about 15 mins to play with it before work.  When I saw the box, I died a little inside.  There on the box was the logo showing it is a DST model.  Ughhh.  Oh well.  I put it together and ran outside for a quick check.  To my surprise this unit gets chatty at about 95.  No bad but a little bit.  The biggest surprise was the all metal thump is there on this one!  This one behaves much closer to the older models.  I've not put it on a ruler yet but all I really needed to see (or hear) was that it successfully grabbed every target in my test area and did it rather well.  Even in disc mode I was getting a 10" dime with correct ID. Dirt at my house is just 2 bars though.  I'm tikled with that result.  This T2 does have BP mode but I didn't even try it. I'm definitely keeping this one and sending the F75 down the road.  

  • Like 5
Link to comment
Share on other sites

2 hours ago, Daniel Tn said:

I received a black T2 that I traded for today and just got about 15 mins to play with it before work.  When I saw the box, I died a little inside.  There on the box was the logo showing it is a DST model.

I think the T2 suits your needs much more than the F75, DST model or not.

Link to comment
Share on other sites

Just some specific and general commentary on this thread discussion…

18 hours ago, GB_Amateur said:

I was operating in Motion All Metal mode.  I varied the sensitivity as well as turning DST on and off (see table below).  I swiped the bullet in two directions.  "Orientation 1 -- axis at coil" in the table below has the bullet oriented pointing at the coil.  For "Orientation 2 -- short side" I swiped the bullet with its axis perpendicular to the coil and in its short direction.  I didn't do any tests perpendicular to the coil sweeping in the bullet's long direction.

Chuck, I’m personally aving trouble visualizing your axis orientation descriptions above but I’m also just naturally challenged at visualizing 3D word problems, I guess.  Specifically, your axis at coil terminology/descriptions, i.e., “pointing at” and “perpendicular to” the coil and “short side” and “long direction” are confusing to me when I consider the bullet’s shape and “in ground orientation” and the plane of the coil and the fact that a DD coil’s active detection “spine”, oriented roughly perpendicular to the sweep path.  For example, a bullet could be oriented roughly vertical in ground (which is my interpretation of what you mean by the axis “pointed at” the coil, but that also means the the axis is “perpendicular” to the coil sweep plane).  Explaining it with a reference to how the bullet would be oriented in the ground assuming a DD coil parallel to the ground perpendicular to the coil sweep path (assuming you were using the stock DD coil) or providing a simple diagram would help (see my crude cave drawing below).

SmartSelect_20230302_080749_PhotoEditor.thumb.jpg.87104646907ff64ba7308c3494890554.jpg

Also, a lot of discussion about air tests here and somebody mentioned that real world, in-ground detection depths would be less than air tests.  You really can’t make a definitive statement like that because soil conditions (moisture, mineralization, and density) and how the soil responds to the detector’s particular operating frequency, and target characteristics can all contribute to make in ground detection depth performance exceed or be significantly less than measured in air tests.  In general, highly mineralized ground will indeed show depth performance significantly less than air tests but this situation would also compress the difference in depth readings vs. the air tests, potentially rendering those differences insignificant.  Example - an air test could show a minie ball for one set of conditions in air to be 14 inches and the other to be 12 inches.  In hot ground, that might translate into 5 inches and 4.5 inches.  Yes even half an inch is not insignificant (miss it by half an inch, miss it by a mile), but just noting that it’s always hard to draw hard and fast conclusions from air tests.  Looking forward to what @Daniel Tn experiences in that bullet field with the T2.

I am also a relic hunter and I could dig minie balls all day long (and have done so) with total enjoyment.  But I love buttons, tokens, ID tags, Corps badges, coins (copper, brass, bronze, nickel, silver, and gold), brass knapsack and uniform accoutrements, belt and cartridge box plates, artillery projectiles, and even ferrous camp objects.  I have found that optimizing my machine choice and setup around a specific target objective or test target type is mostly counter productive unless I am solely seeking that target type.  Not saying this is the case, but that T2 may kill on lead minies but might turn out not being all that on buttons or other relics, for example, under certain conditions, because you are limited to a single frequency while dealing with an infinite number of variables.  It is the reason I moved from single frequency, to selectable single frequency, and now to simultaneous Multifrequency and really haven’t looked back.  Plus I subscribe to the @Steve Herschbach school of thought:  VLF when you can, PI if you must.  Yep, I still have my venerable MXT, F75, and a G2+.  But that’s mostly nostalgia mixed with wanting to retain at least one machine that still accommodates concentric wound coils (which is why I did got rid of my T2).  Though I haven’t used them for that reason for close to 5 years now.  But this thread has tempted me to re-visit the F75 and consider marrying it up to Fisher’s latest coil just to see what it can do, perhaps even in my planned visits to Culpeper this month.  Though to be honest, I’ll probably just run the Axiom and bring along my D2 in my day pack as a backup.

Again, would like to hear how the T2 works out for Daniel on bullets and relics in general.  I understand the desire to neck down to as few machines as needed, and for my part will start thinning the herd soon.

GL. HH.

  • Like 2
Link to comment
Share on other sites

Chase -- Are you referring to the newer 12" weird looking coil by Fisher?  I have one for the F75 you can borrow if you don't have one. No sense in paying $200 just to try one. I did not notice any real difference in depth over the stock coil but it certainly is lighter weight. I ordered the Super Fly coil for the T2 last night.  I really liked those machines paired with the DeTech Ultimate 13 coil...but that Super Fly looked bad to the bone.  

  • Like 4
  • Thanks 1
Link to comment
Share on other sites

1 hour ago, Chase Goldman said:

Just some specific and general commentary on this thread discussion…

Chuck, I’m personally aving trouble visualizing your axis orientation descriptions above but I’m also just naturally challenged at visualizing 3D word problems, I guess.  Specifically, your axis at coil terminology/descriptions, i.e., “pointing at” and “perpendicular to” the coil and “short side” and “long direction” are confusing to me when I consider the bullet’s shape and “in ground orientation” and the plane of the coil and the fact that a DD coil’s active detection “spine”, oriented roughly perpendicular to the sweep path.  For example, a bullet could be oriented roughly vertical in ground (which is my interpretation of what you mean by the axis “pointed at” the coil, but that also means the the axis is “perpendicular” to the coil sweep plane).  Explaining it with a reference to how the bullet would be oriented in the ground assuming a DD coil parallel to the ground perpendicular to the coil sweep path (assuming you were using the stock DD coil) or providing a simple diagram would help (see my crude cave drawing below).

SmartSelect_20230302_080749_PhotoEditor.thumb.jpg.87104646907ff64ba7308c3494890554.jpg

Also, a lot of discussion about air tests here and somebody mentioned that real world, in-ground detection depths would be less than air tests.  You really can’t make a definitive statement like that because soil conditions (moisture, mineralization, and density) and how the soil responds to the detector’s particular operating frequency, and target characteristics can all contribute to make in ground detection depth performance exceed or be significantly less than measured in air tests.  In general, highly mineralized ground will indeed show depth performance significantly less than air tests but this situation would also compress the difference in depth readings vs. the air tests, potentially rendering those differences insignificant.  Example - an air test could show a minie ball for one set of conditions in air to be 14 inches and the other to be 12 inches.  In hot ground, that might translate into 5 inches and 4.5 inches.  Yes even half an inch is not insignificant (miss it by half an inch, miss it by a mile), but just noting that it’s always hard to draw hard and fast conclusions from air tests.  Looking forward to what @Daniel Tn experiences in that bullet field with the T2.

I am also a relic hunter and I could dig minie balls all day long (and have done so) with total enjoyment.  But I love buttons, tokens, ID tags, Corps badges, coins (copper, brass, bronze, nickel, silver, and gold), brass knapsack and uniform accoutrements, belt and cartridge box plates, artillery projectiles, and even ferrous camp objects.  I have found that optimizing my machine choice and setup around a specific target objective or test target type is mostly counter productive unless I am solely seeking that target type.  Not saying this is the case, but that T2 may kill on lead minies but might turn out not being all that on buttons or other relics, for example, under certain conditions, because you are limited to a single frequency while dealing with an infinite number of variables.  It is the reason I moved from single frequency, to selectable single frequency, and now to simultaneous Multifrequency and really haven’t looked back.  Plus I subscribe to the @Steve Herschbach school of thought:  VLF when you can, PI if you must.  Yep, I still have my venerable MXT, F75, and a G2+.  But that’s mostly nostalgia mixed with wanting to retain at least one machine that still accommodates concentric wound coils (which is why I did got rid of my T2).  Though I haven’t used them for that reason for close to 5 years now.  But this thread has tempted me to re-visit the F75 and consider marrying it up to Fisher’s latest coil just to see what it can do, perhaps even in my planned visits to Culpeper this month.  Though to be honest, I’ll probably just run the Axiom and bring along my D2 in my day pack as a backup.

Again, would like to hear how the T2 works out for Daniel on bullets and relics in general.  I understand the desire to neck down to as few machines as needed, and for my part will start thinning the herd soon.

GL. HH.

Nice post Hugh, and rather a general one but that's good since not everyone has the 'background' knowledge, particularly with a specific detector model.  I think I agree with everything you said (after one readthru).  I'll try to answer what is specifically directed at my post.

Yes, your drawing is consistent with my air test measurements.  I should have done a better job (with drawings or photos) than counting simply on words which sometimes can be confusing.

My intent (there's that word again 😁) was to confirm/refute the measurements Daniel made with his F75, not to claim he made a mistaken measurement but rather to ask "do all of the DST models of the F75 give weaker air test performances than the original non-DST models?"  I was definitely not implying that my results (or his) would carry over to actual in-ground targets.  (You knew this but maybe others didn't....)  Also, since he used a Civil War(CW) bullet I tried as close as possible to use a similar target, although that alone was a 'weakness' of my test.  At least mine was smaller, not larger, but I think it's likely the composition is different.   BTW, no one has yet answered my question about CW bullet composition.  JCR talked about bullets in general, though.  During a Google search I did see a claim that CW bullets were pure lead, but that was from a metal detecting forum post (not our beloved DetectorProspector.com forum) so I was unsure of its veracity.

My F75 is a great backup detector to the Minelab Equinox 800 and soon it will be 3rd in line, but still not going anywhere.  I've always found it deep, but it's not (in my experience) very good at ID'ing coins nearly as deep in-ground as the Eqx 800.  Part of that is surely its single frequency (13 kHz) vs. the Eqx multifrequency (~5-6 kHz combined with ~38 kHz, with maybe one other freq in-between).  Been said before and worth saying again -- it (ditto its older cousin, Teknetics T2) is still the best ergonomic design out there that I'm aware of.  (Now I've started another detector war....  🙄:biggrin:)

  • Like 3
Link to comment
Share on other sites

47 minutes ago, Daniel Tn said:

Chase -- Are you referring to the newer 12" weird looking coil by Fisher?  I have one for the F75 you can borrow if you don't have one. No sense in paying $200 just to try one. I did not notice any real difference in depth over the stock coil but it certainly is lighter weight. I ordered the Super Fly coil for the T2 last night.  I really liked those machines paired with the DeTech Ultimate 13 coil...but that Super Fly looked bad to the bone.  

Daniel,

Thanks greatly for the info on that 12" coil.  First person I've heard of that has actually used it!  I was looking at it mainly for weight and reduced footprint in hot dirt.  I have a 13" Ultimate on the F75 right now.  I will look into the Super Fly, and thanks greatly for the offer to borrow and try that new coil.  I'll PM you if I decide to try it out after all.  I think I will bring the F75 to Culpeper at least with the stock and bake it off against the D2, Nox 900, and Legend on Minies.  Right now focusing on getting half way proficient on the Axiom b4 the trips down.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...