Digalicious: said:
Thank you for that Monte.
Sooooo, while you're here, are you able to answer my question?
You are welcome ....
I figured you would ask. So,
, I can try ... but
I am not up on a D2, or a Legend, and haven't had a clear understanding of what it is or how it works.
What is Iron Bias or whatever term a manufacturer uses? Like most others I haven't seen a really good explanation that describes what it is, why we have it, and why some offer that adjustment in SMF and not SF.
It isn't Discrimination because that basically establishes an accept or reject point. The inference to the word 'Bias' might help describe the amount of receive signal from Iron to be accepted and processed.
Why might it only be a function on a SMF model and not a SF? How about a little reverse thinking?
If we really knew what it is and how it works, then we might ask it this way:
IF we had it on a SF model that has been in use and we were familiar with it, and IF we could see any benefit in it, would we want that adjustment on a SMF device?
And to further question what it is or how it works, we should select a few current or recent SF models that we use that seem to work great in Iron for unmasking a good non-ferrous target, and locate some naturally-lost targets in the wild and compare performance, side-by-side, with a SMF model using comparable coils and settings.
I have done just that, and even started out yesterday checking a small renovation site to show a fellow and used the Equinox 800 in the four MF Disc. modes. The most observed debris was Iron Nails, but there was other ferrous and non-ferrous trash on or just under the ground surface. I wanted to find an OK non-ferrous signal and then check out the modes using all of the IB settings, low-to-high. Then I could grab one of a few SF units I have and use in Iron and compare performance on that naturally-located target.
I could hear the low-tone Iron responses but did sweep over a high-tone target. It was a partially-exposed Wheat-back Cent. I encountered it when facing west and swept over that coin in 4 directions, from the left and from the right. A potential of 8 good hits IF the target wasn't masked by the very close debris. The good and bad metal targets were so close it made it difficult to get a dig-worthy non-ferrous response, and using the four Disc. modes in 2-Tone and 5-Tone and all of the IB settings in each mode, the conclusion was obvious.
The best performance with the abundant, closely-oriented Nails and other debris was an IB of '1'. A setting of '2' or '3' were usable, but you could start to hear some impaired performance, and very noticeable with a setting of '4', '5' and '6. Higher settings resulted in only one or two clear hits on the coin. The best performance with the lowest Iron Bias setting in any of those modes was 4 or 5 hits and maybe 1 or 2 iffy-signals that were not interesting enough to check out.
I then checked out several SF models. A 10 kHz Bandido II µMAX w/6" Concentric, a 13 kHz F-75+ w/5" DD and 3½X6½ Concentric, a 14 kHz Racer 2 w/
'OOR' DD, a 19 kHz FORS Relic w/5" DD and 19 kHz Time Ranger Pro w/5" DD. None of these Single-Frequency models feature any sort of "Iron Bias" adjustment.
The results? ALL of the SF models, using the same sweep routes on the undisturbed coin, produced at least 6 solid hits and both of the 'iffy' responses were good enough to investigate. The Racer 2, FORS Relic and TRP all gave a possible 7th worthy hit.
One last thing to 'test'. i grabbed the Equinox 800 w/6" DD coil and in Field 1 MF w/Iron Bias at '1' for best response, I then selected the Single Frequencies and re-swept the coin, also using all four Disc. modes of Park 1 and Park 2, Field 1 and Field 2.
At 4 kHz there was, at best, only 2 good hits. At 5 kHz it was slightly better as one bad iffy almost sounded good. At 10 kHz the responses were almost the same as when in SMF. The better EQ-800 performance was at 15 kHz and 20 kHz with audible hits that were
almost as good as my SF units.
The good thing
for me is that I did not acquire the EQ-800 for use in my Iron contaminated Relic Hunting sites but more for the urban Coin Hunting I'll do in low to moderate trashy places. I already have a very good set of detectors and coils to deal with ferrous challenges.
Monte