Cody, can you verify this with you r contacts at Minelab...

[Anonymous]

Sort of running all the discussion about semi-auto and manual sensitivity together, I've come to a possible conclusion.
Is it possible that the factory selects semi-auto 16 because the algorythm will allow a maximum of 15 points up AND/OR down? We had a post a while back by one fellow who said semi-auto one was roughly equivalent to 18 I think (pretty close to 16-17!) and I've seen others post where in good soil and semi-auto 31 that their detector doesn't go as deep as manual 21-24.
So then, is it possible that semi-auto 31 wraps back around in good soil, and actually goes to 32 then 1,2,3,4, etc as it finds the soil conditions improving?
In other words, semmi-auto any number other than 16 might in fact be self defeating! I can't say for sure, but anecdotal evidence from this board and others led me to this conclusion.
I think we'd like to think that semi-auto sets the topmost point the machine tries to achieve during operation, but there is pretty solid evidence that this is not the case. Someone at Minelab ought to be able to put this one to rest in a heartbeat. Let's not forget, opertors manuals are rarely written by the engineers directly, so the true operational characteristics may or may not be what we see in the manual on page 49.
If we use the text from the manual "...semi-automatic mode...and will adjust actual detector sensitivity as close as possible to your specified level of sensitivity...". This can be show to be patently incorrect if we set the sensitivity to semi-auto 1.
In any event, it all just sort of came together and "gelled" as it were, so if you could verify or discount this concept with your Minelab contacts, we will have put one issue to bed. My hope is we won't spin our wheels discussing and rediscussing these things, rather we will have solid operational notes which we can put into an FAQ style repository.
DAS

 

[Anonymous]

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[Anonymous]

Varmint,
Never thought about it in those terms before but think you are right. From what most of us have found from experimenting a setting a 16 would allow the detector to span the entire sensitivity range in Auto. That would be a darn good reason it is the factory default.
I don't think it "wraps around". But do think it could vary over the entire scale as conditions change. Also not sure how the algorithm works. If a higher number "pushes" the algorithm to try harder or it just adjusts to the conditions it is looking for regardless of settings. As I posted to Rick(ND) below I've seen a few times where the machine goes nuts in Auto- won't ever get stable until you turn it off and start over.
I think the issue of whether Auto works as advertised in the manual has been put to bed, it obviously doesn't. But the issue of whether you find more coins in Auto or Manual over the long run in most soild conditions will probably be debated here forever.
Good Post
Chris

 

[Anonymous]

I think you are right in the area of how the semi-auto works. I am going to check it out as I only brushed over the topic the last time we talked. I have done a lot more checking now and have more questions.
I will ask for a explanation and see where that goes.
HH