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Single Frequency Iron Rejection


Luis

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Normally I run the equinox in multi-frequency mode, but yesterday I tried to use it at 5Kz in field mode 1. Lately I am hunting with the Iron filters at 0, but I did not like it in the single frequency mode so I went to modify it and what was my surprise  it wouldn't let me enter the submenu to upload iron rejection.  I tried it with the partner's equinox in case it was a failure of mine and the same thing happened.  In single frequency mode it does not let you enter the iron rejection submenu.  Do you know what the reason is?

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Yes, the lack of Iron Bias in single frequency is described in the manual (p. 52) and has been discussed previously on the forum.  Iron Bias is implemented as part of Multi IQ signal processing and requires a multi frequency signal to get the required real-time, frequency dependent response information from the target for Iron Bias to do its thing.  Therefore, it is disabled in single frequency.

 

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In Multi IQ the I, In-Phase multiple signals which are more sensitive to iron signals from iron targets and especially iron mineralization are ignored and the  multiple quadrature signals which are mostly non-ferrous target signals are used to identify the target. The Iron Bias settings help provide user customizable iron identification adjustments when needed. 

In single frequency detection with the Equinox the ratio between both the I and Q signal are used to identify the target so no Iron Bias is necessary. 

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6 minutes ago, Jeff McClendon said:

In single frequency detection with the Equinox the ratio between both the I and Q signal are used to identify the target so no Iron Bias is necessary. 

Jeff I know you know this, but for the benefit of others, that last phrase (I.e., “no Iron Bias is necessary”) could be misinterpreted by folks to imply single frequency and use of I/Q ratio to ID targets is a superior ferrous target identifier, but actually the opposite is true.  It gets fooled frequently by wraparound and other single frequency limitations such that falsing is a significant issue in SF.  IMO if you are never using IB while operating in Multi (i.e., always leaving it at 0) you are leaving a significant, available tool on the sidelines. The ability to dial in F2 bias as necessary is a great feature.

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I totally agree.

Iron bias enhances the identification of iron signals using Multi.

The use of both I and Q signals in single frequency does not make the Equinox detect iron more accurately in my opinion or from experience. Others who use Equinox in single frequency in mild ground conditions may disagree. 

I rarely use the single frequency choice on the Equinox unless it is absolutely necessary due to EMI or if I want to experiment a little. My Equinox detectors stay in Multi frequency for all detecting with F2=0 or 1 for gold prospecting and F2= whatever I want to set it on for other detecting.

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