I wanted to bust out today and get some swing time on the F4 , but it wasn't to be with the rain storm that blew in. I decided to get some time on it indoors testing the various three coils it came with.
Here's the notes from my air testing, using the All Metal Discrimination mode, with MAX SENS:
4" Gold Nugget Coil:
Coil was fairly sensitive to small gold, hitting a #10 screen flake/nugget at about a .5" depth, and
a .75 gram nugget would air test to slightly over 2".
Various mens gold rings (different sizes, and karat) would hit right about 5-6", and would for the most part sound off as 5C/PT or PT,
Womens gold rings (smaller diameter bands) would hit right at 5" and would sound off between foil and 5C/PT.
Silver and clad quarters would trigger right at 5". The clad displayed a slightly lower TID (high 70's) whereas the silver quarter would basically stick in the low 80's.
Silver dimes TID ~ 70-71 (give or take) with clad dimes bouncing around 68 - 70, both pickup at about 4.5" deep.
Zinc penny hits around 5", and all over the TID map depending on depth. A copper wheatie around 4" hit with fairly solid TID's of 68 or 70 (never hit 69 oddly), higher depth around 5" + it would detect, but the TID would be erratic.
Nickel 4" and less, solid TID at 32. Higher then 4" the TID bounced until it could no longer see it at about 5.5".
8" Concentric coil:
Various mens gold rings hit right about 8", and would for the most part sound off as PT, whereas womens gold rings (smaller diameter bands) would hit right at 8" and would sound off between 5C/PT and PT.
Clad quarter hits right about 8", TID's around 77 - 79.
Silver quarter hits right around 8", TID's around 80, 82 or 83.
Clad dimes hit right about 6" and TID's around 68 or 70, silver dimes hit at about 7" and TID at 70 - 71
Zinc penny hits about 8", TID all over the map depending on depth, copper wheatie around 7", TID at 68 or 70.
Nickel TID stable at about 30 or 32 from 4" of depth (higher depth was erratic).
DD Coil (had to bump the SENS down two notches from MAX, else TID was acting like it was getting EMI):
I had hight hopes for the DD coil, but I'm not sure what to make of this coil from an air test.
The sweet spot was from 2" - 6" of depth with consistent TID's, but depth more then 6" and they were erratic, also from 0-2" they were really erratic, as if bouncing all over the surface of the coil. I assume (hope) this isn't the way it operates in ground, but was a bit surprised with the air test performance.
In All Metal Discrimination I guess you can't disc iron (hence the term ALL METAL DISC I suppose), but it will show you the TID's, depth, etc. I was kind of hoping that in AM DISC mode I could still disc out iron.
Pinpoint mode for nuggets wasn't bad, gives some indication of depth on the large TID LCD and appeared to go a bit deeper then the other modes.
One question I had is that I've seen some mention of using the F2/F4 as a casual prospecting detector using the 4" Gold Nugget coil. It would seem you would want to use either the Pinpoint, Auto Tune All Metal, or All Metal DISC mode for this, but how would you reject black iron sand ?
Here's the notes from my air testing, using the All Metal Discrimination mode, with MAX SENS:
4" Gold Nugget Coil:
Coil was fairly sensitive to small gold, hitting a #10 screen flake/nugget at about a .5" depth, and
a .75 gram nugget would air test to slightly over 2".
Various mens gold rings (different sizes, and karat) would hit right about 5-6", and would for the most part sound off as 5C/PT or PT,
Womens gold rings (smaller diameter bands) would hit right at 5" and would sound off between foil and 5C/PT.
Silver and clad quarters would trigger right at 5". The clad displayed a slightly lower TID (high 70's) whereas the silver quarter would basically stick in the low 80's.
Silver dimes TID ~ 70-71 (give or take) with clad dimes bouncing around 68 - 70, both pickup at about 4.5" deep.
Zinc penny hits around 5", and all over the TID map depending on depth. A copper wheatie around 4" hit with fairly solid TID's of 68 or 70 (never hit 69 oddly), higher depth around 5" + it would detect, but the TID would be erratic.
Nickel 4" and less, solid TID at 32. Higher then 4" the TID bounced until it could no longer see it at about 5.5".
8" Concentric coil:
Various mens gold rings hit right about 8", and would for the most part sound off as PT, whereas womens gold rings (smaller diameter bands) would hit right at 8" and would sound off between 5C/PT and PT.
Clad quarter hits right about 8", TID's around 77 - 79.
Silver quarter hits right around 8", TID's around 80, 82 or 83.
Clad dimes hit right about 6" and TID's around 68 or 70, silver dimes hit at about 7" and TID at 70 - 71
Zinc penny hits about 8", TID all over the map depending on depth, copper wheatie around 7", TID at 68 or 70.
Nickel TID stable at about 30 or 32 from 4" of depth (higher depth was erratic).
DD Coil (had to bump the SENS down two notches from MAX, else TID was acting like it was getting EMI):
I had hight hopes for the DD coil, but I'm not sure what to make of this coil from an air test.
The sweet spot was from 2" - 6" of depth with consistent TID's, but depth more then 6" and they were erratic, also from 0-2" they were really erratic, as if bouncing all over the surface of the coil. I assume (hope) this isn't the way it operates in ground, but was a bit surprised with the air test performance.
In All Metal Discrimination I guess you can't disc iron (hence the term ALL METAL DISC I suppose), but it will show you the TID's, depth, etc. I was kind of hoping that in AM DISC mode I could still disc out iron.
Pinpoint mode for nuggets wasn't bad, gives some indication of depth on the large TID LCD and appeared to go a bit deeper then the other modes.
One question I had is that I've seen some mention of using the F2/F4 as a casual prospecting detector using the 4" Gold Nugget coil. It would seem you would want to use either the Pinpoint, Auto Tune All Metal, or All Metal DISC mode for this, but how would you reject black iron sand ?
