Frequency Weighting and Other Secrets

[ohmygato]

Sorry for another potentially redundant question. I have not been completely satisfied with the results I've gotten trying to look this up.

I've seen in several Manticore videos that the user talks about a standard program being "weighted" towards certain frequencies. And I've read a few posts confirming that there is some Minelab secret sauce in their programs, that they have some frequency weighting that allows them to hit better on high conductors or low conductors. And that it is always some secret sauce of MultiIQ+ or whatever the marketers call it but the ingredients to that sauce are not shared.

All else equal (meaning that if I manually adjust all settings to be the same) between two different programs, will All Terrain High Conductor perform better on high conductors due to it being "weighted" to the right frequency secret sauce?

Are there any other secrets Minelab is holding back about the differences in programs?

This makes me think that if I'm mainly going for silver I should be in a high conductor program, and if I'm going for gold I should be in a low conductor program, and that I should change the settings of that program to meet my needs, because those programs are naturally going to perform better on those targets that they are weighted towards.

Early on when learning this thing I also wondered why they didn't have any slots for completely custom programs like they do with the DFX for example, and now I'm starting to see why... there appear to be settings going on behind the scenes that Minelab doesn't let users change, and that starting a complete from scratch would be nearly impossible due to the user not knowing how to weight the frequencies etc.

 

[Diga]

Weighting just means the primary frequency that is utilized in a particular SMF mode.

In general, low weighted frequencies hit high conductors / larger targets a little better and also unmask the good stuff from nonferrous trash better than higher weights. Higher weighted frequencies do the opposite of that.

Other factors like the type of ground mineralization play a role as well, but we'll start with that

 

[ohmygato]

Weighting just means the primary frequency that is utilized in a particular SMF mode.

In general, low weighted frequencies hit high conductors / larger targets a little better and also unmask the good stuff from nonferrous trash better than higher weights. Higher weighted frequencies do the opposite of that.

Other factors like the type of ground mineralization play a role as well, but we'll start with that

I understand that. What I don't understand is if Minelab does in fact weight programs more towards higher or lower frequencies, and if there are other settings differences between programs that they don't tell us.

In other words, is it generally better for me to be using All Terrain High Conductor if I'm looking for deep silver and if I optimize all the other settings for my needs (because this program is frequency-weighted by the factory to perform best on high conductors)?

 

[Beachhunt1]

Other factors like the type of ground mineralization play a role as well, but we'll start with that

EMI is a cause for concern with frequencies.

 

[Carl-NC]

Frequency weighting can take place at the transmitter, in the receiver, or both. The best results are when it's done at the transmitter. The image below shows the Equinox Park mode waveform. It has a low frequency of 2.6kHz, a main frequency of 7.8kHz, and a high frequency of 39kHz.

The 2.6kHz component is rather weak while 7.8kHz is dominant. It would be possible to alter the waveform to boost the 2.6kHz component at the expense of the 7.8kHz and/or the 39kHz components, which would improve high conductor responses. I don't have a Manticore so I can't speak to what is really going on, but I would expect something like this. The only way to know for sure is to measure the TX waveform.

It is also possible to alter response weighting on the receive side, but doing it that way means you're probably suppressing undesired responses instead of boosting desired responses. The DFX did this.

 

[ohmygato]

Here's a thread that talks about the Equinox weighting as well: https://metaldetectingforum.com/ind...ed-frequencies-on-minelab-equinox-800.290035/

The strange thing to me is that Minelab does not say what the differences are even in general terms (such as "MultiIQ frequency weighting is optimized for high conductors"). There is also some vague stuff about "Coke rejection".

However it seems like if I'm searching for high conductors in a pasture then I should start with the All-Terrain High Conductors program and tweak it for my needs, because no matter how much tweaking you do to All-Terrain General you can never get to the optimal frequency weighting.

Is this correct? Are there other settings behind the scenes in the various programs that they're not telling us about?

 

[Carl-NC]

However it seems like if I'm searching for high conductors in a pasture then I should start with the All-Terrain High Conductors program and tweak it for my needs, because no matter how much tweaking you do to All-Terrain General you can never get to the optimal frequency weighting.

Is this correct? Are there other settings behind the scenes in the various programs that they're not telling us about?

Minelab is very secretive (and sometimes misleading) about technical details. They don't even tell you what frequencies are being used in any given mode. I don't understand why as it's pretty easy to measure, users are keenly interested in it, and giving this information doesn't harm the company in the least. But I would say you are correct, use the program that matches closest to what you want to find and tweak from there. The best way to sort things out is with a test garden.

 

[Rudy]

Minelab is very secretive (and sometimes misleading) about technical details. They don't even tell you what frequencies are being used in any given mode. I don't understand why as it's pretty easy to measure, users are keenly interested in it, and giving this information doesn't harm the company in the least. But I would say you are correct, use the program that matches closest to what you want to find and tweak from there. The best way to sort things out is with a test garden.

Carl, it is easy to measure if they are only doing it on the transmit side, not so easy to know what they may be doing on the receive side (if they are doing anything on the receive side).

 

[Cherry Picker]

I would think finding the primary frequencies used would be a matter of testing a coin in each single frequency. Find the best/matching results on a coin with a single frequency, and you probably will know what one of the primary frequencies used in a SMF program.

 

[ohmygato]

I would think finding the primary frequencies used would be a matter of testing a coin in each single frequency. Find the best/matching results on a coin with a single frequency, and you probably will know what one of the primary frequencies used in a SMF program.

I'm going to switch to ATHC for my next open pasture hunt expecting to find 5X the number of silvers I've pulled from there already. Then I am going to switch back to ATG on those new targets and prove that it can't find them, then experiment with the single frequency settings over those same targets as well.

 

[spence]

Frequency weighting can take place at the transmitter, in the receiver, or both. The best results are when it's done at the transmitter. The image below shows the Equinox Park mode waveform. It has a low frequency of 2.6kHz, a main frequency of 7.8kHz, and a high frequency of 39kHz.

View attachment 607264

The 2.6kHz component is rather weak while 7.8kHz is dominant. It would be possible to alter the waveform to boost the 2.6kHz component at the expense of the 7.8kHz and/or the 39kHz components, which would improve high conductor responses. I don't have a Manticore so I can't speak to what is really going on, but I would expect something like this. The only way to know for s is to measure the TX waveform.
It is also possible to alter response weighting on the receive side, but doing it that way means you

're probably suppressing undesired responses instead of boosting desired responses. The DFX did this.

I don't understand the image with out units of frequency labeled ? Curious if that was an actual screenshot from a spectrum analyzer or other test equipment?

 

[spence]

I don't understand the image with out units of frequency labeled ? Curious if that was an actual screenshot from a spectrum analyzer or other test equipment?

Found it . Sorry