Another way to do a masking test.

[dahut]

Has anyone ever disputed iron halo ? Your right re the YouTube tests. Majority are contrived. An interesting masking test is to use a tiny staple and see what that masks out.

There is always someone to dispute it, Brian... there is always someone to dispute anything.
Myself, I reckon that iron and it's masking effects are the greatest challenge we face in the soil.

 

[UK Brian]

The main purpose of the halo theory seems to be to sell a poor performing machine by suggesting that in the field the performance is going to be much better. I would say that if you have a coin of poor quality metal it will create a halo in time but the item is not going to be collectable.

Thousand year old pure gold and silver comes out as good as the day it was buried so the most sort after metals will not gain from any halo advantage. You could suggest that some depth gain might be made if there's a bit of metal nearby to act as a sacrificial anode but really halo should be disregarded as a "good" thing because as you say iron is one of the most troublesome things in metal detecting.

One interesting tit bit is that pulse machines that are so sensitive to iron don't pick up iron halo.

 

[UK Brian]

There's lots of tests that a few doggy dealers would do in the past that would "show" wonderful feats of depth, sensitivity, iron reject or iron see through. Some of these have moved on line and appear to work but are of no use in the field.
Often you see a coin on a lump of iron and the detector still picks it up. In fact the detector has been set up to just, JUST, reject the ferrous. Then add the coins extra bulk and the detector sounds off. Its something that just doesn't work in the field.
One of the first ever You Tube test showed a detector getting great depth on a small silver coin. This was achieved by offsetting the ground balance so much that the coin was detected but they failed to show that the detector sounded off on every fragment of metal and patch of mineralisation.

There's lots of little fiddles. Use to be that if you saw a magazine field test and they said "I didn't have time to get to the beach" you could guarantee it would not work on the wet sand. One brand would have their full page add in a magazine and say something along the lines of "brand X took first three places in the XXXX detecting competition". What they didn't mention was that the competition was limited to their machines only .You can't beat borrowing a detector and trying it yourself. It's still buyer beware.

 

[dahut]

There's lots of tests that a few doggy dealers would do in the past that would "show" wonderful feats of depth, sensitivity, iron reject or iron see through. Some of these have moved on line and appear to work but are of no use in the field.
Often you see a coin on a lump of iron and the detector still picks it up. In fact the detector has been set up to just, JUST, reject the ferrous. Then add the coins extra bulk and the detector sounds off. Its something that just doesn't work in the field.
One of the first ever You Tube test showed a detector getting great depth on a small silver coin. This was achieved by offsetting the ground balance so much that the coin was detected but they failed to show that the detector sounded off on every fragment of metal and patch of mineralisation.

There's lots of little fiddles. Use to be that if you saw a magazine field test and they said "I didn't have time to get to the beach" you could guarantee it would not work on the wet sand. One brand would have their full page add in a magazine and say something along the lines of "brand X took first three places in the XXXX detecting competition". What they didn't mention was that the competition was limited to their machines only .You can't beat borrowing a detector and trying it yourself. It's still buyer beware.

Teh fact remains the we are not really detectorists, but rather "recoverists." Detecting is just the means to an end.