Iron Bias - What It Is

[Ferrous Grump]

I know of an old home site that had a tin roof.  Iron is everywhere!  I should raise the iron bias to cancel out the abundance of iron to allow the machine to find the non-ferrous items (canning jar lids, etc)?

 

[Tom Slick]

I started using the Nox 800 in Park 1 with the factory setting of 6 on the I/B. Most all my detecting is now done around old home sites, lots, and ghost town sites. As I became more familiar with the Nox, I started lowering the I/B gradually and now only run it at "0". I found that by running the lower I/B that I could go back to areas I had hunted before and continue to pull more non-ferrous each time I lowered it. I dig a little more iron now but the unmasking benefit makes it worth it to me. If I was traveling and only had the opportunity to hit a spot once, I'd increase the I/B to basically cherry pick it, but I feel the lower the I/B the better, if you don't want to miss anything. 

I've been detecting for about 45 years and my hearing is still very good. I most always hunt with the disc set a zero or with the horseshoe button engaged. I make most all my dig or no-dig decisions on what I hear. The meter comes into play on those signals that my ears can't decipher. Most of the time, I'm looking for reasons to dig a target, not reasons to not dig it.

If I'm hunting a modern park and looking for clad and jewelry, I set the I/B at 6 but around iron infested sites I'll run the I/B at zero with my first tone break set to zero and my first bin volume also set to zero. I don't need to hear the iron "to keep me on the site" as the sites go from this fence to that fence, or I can just keep a look out for rusted cans. 
That's how I do it, anyone else?

 

[Steve Herschbach]

I’ve been running Iron Bias at 0 since day 1 and posted pretty early on saying so. Usually the only time I don’t is if I revert to stock settings for some reason and forget to dial it back to zero.

If I was not digging any ferrous frankly I would think something is wrong. A machine that never digs ferrous is a machine missing some non-ferrous.

[LukeJMG1986]

I'm confused about iron bias. I hunt a trail head that use to be a junk yard. Needless to say it's packed to the gills with trash. Would I want to slightly increase iron bias? Or leave it at the factory preset (which is zero I believe) Also, will increasing the iron bias increase the odds of missing gold or silver?

[Chase Goldman]

Well things have changed since this was written because ML has come out with an update that includes two different iron bias filters  - The Original called FE and a new one called F2.  F2 seems to have a greater range of effect than FE so I use that as my iron bias filter instead of FE.  The default setting for F2 is 6 for all modes (EQ 800) or 2 for the EQ 600.  The primary purpose of the Iron Bias filter is to force probable iron to sound like iron (low tone) instead of falsing high which tends to happen with bent rusted nails and larger, flat pieces of iron.  It is not 100% effective.  If you push it to high levels, you are more likely to get the iron to false less, but as with any filter you may also suppress the ability of the detector to separate true non-ferrous targets from nearby ferrous junk.  I think running F2 between 4 and 6 (F2 = 4 is approximately equivalent to FE=0) is a good balance between getting less iron falsing while still providing some ability to separate non-ferrous from ferrous targets.  It is not an exact science and any time you use either discrimination alone or in combination with an iron bias filter you run the chance of missing a keeper.  I like to run with the horseshoe button engaged to remove all discrimination even though I use F2 = 4 to 6, so that I can hear the iron tones and decide based on what I am hearing whether I want to dig the target.  An F2 setting of less than 4 tends to get noisier, with F2 = 0 really not a pleasant experience in thick iron.  HTH.

There is more discussion of the effect of the latest Equinox update on the iron bias settings here, advice on how to adjust iron bias by trial and error here, and video showing the difference in iron bias settings FE and F2 in mineralized ground hunting relics here.  Avid beach hunter discusses how iron bias affects beach hunting here and here.  HTH

[Phillips_R]

Is this new filter parameter a required software upgrade that should be made?

 

[Sinclair]

5 hours ago, Phillips_R said:

Is this new filter parameter a required software upgrade that should be made?

 

After the update, you have the ability to switch between the old and the new mode - you loose nothing there.. instead you gain more options.