From Euphoria To Despair

[schoolofhardNox]

2 hours ago, Chase Goldman said:

You are asking some great questions that I can't really answer because I have not done a deep dive into the available technical information on the GPX 6000 (other than reading the 6000 user manual) wrt to how it implements EMI mitigation- which knowing ML - I am sure is sparse and/or amibiguous - lol.   I want to caveat the statement in my previous post regarding the opposite currents cancelling noise in the two D coils - that is one way to take advantage of symmetric dual coils but I do not know if that is the specific ML implementation.  All I can say based on the user manual information is that it compares signals in the two coils in both EMI and Ground Cancel mode and utilizes the signal comparison to implement the cancellation of common EMI or ground noise signals.

Anyway, from what I can tell, ML is also utilizing some sort of EMI mitigation algorithms for mono coils too and I assume they can apply that algorithm to the DD regardless of whether it is in EMI noise or ground noise (conductive/salt ground) cancel (that is implied by the noise cancellation guidance on pages 13, 14 and 19-21 of the user manual).  So I definitely thought of you regarding what setting would work best on your EMI saturated beaches that you hunt in the "cold" seasons.  I presume when on your beach sites, you will need the DD in conductive ground cancel mode for the salt and then see if you can mitigate EMI using the EMI cancel algorithm.  If EMI is still unbearable, then I would experiment to see if you could actually get the 6000 to run stable on the beach in EMI cancel mode.  It looks like you have one of those excruciating "either or" situations since you apparently can't run in EMI cancel mode and "Salt" cancel mode simultaneously.  Really looking forward to what you find out on the beach and hopefully you can find a sweet spot settings wise.  GL HTH

Thanks Chase. That is what I was going to try first. Run it to cancel ground/salt and take what it gives me for EMI mitigation. If that doesn't work at all, then I'll try EMI cancel, hopefully that will be better and deeper than my 5000 in cancel mode. It won't take too long to get some settings chosen, since the combinations are limited by options available. On the 5000 you could spend your whole life trying all the possible combinations for maximum performance. It took me a quite a while to get  the right combination of settings for deep silvers at these beaches with the 5000. With the 6000 it will either work or not, but at least I will know reasonably fast. As for Minelab, it could take years before some very smart people can figure out how things work. Until then I believe it's healthy to speculate about what we think is going on. No shame if we are wrong as far as I'm concerned. I think Minelab does this on purpose and gets a kick on watching us squirm and strain our brains to try and figure out what is happening inside their machines 😄

[rvpopeye]

A My World analogy...

Pro sound microphones , as well as other higher level signal wires use a form of this ("Balanced Lines" ) to cancel out noise in the long , low level signal wiring runs... called "Common Mode Rejection". A stage is a high EMI area !

Each mic wire has one ground (attached at one end only to eliminate ground loops) and TWO hot wires , 180* out of phase from each other.....when they are summed up on the receiving end the identical induced (noise) signals cancel each other out and the audio signal remains  but noise (EMI) free.

JMHO,,,I suspect the detectors use similar theory to accomplish the rejection.....

[Bryan]

On 8/19/2021 at 5:58 PM, 1911Colt said:

For a ridiculous $6,000, they ought to just send you a whole new unit no questions asked, in fact I would demand it, the one you got could be a lemon giving you problems for years to come.

They did. Immediately.