Excel GB and hot rocks.. This could only happen to me :blink:

[Jackpine Savage]

Yesterday I hit a couple different fields looking for some old homesites and ran into something I had never seen before with the Excel. I had gone from one field with a sandly loam type ground to one with a heavier clay soil. When I turned the Excel on to GB it at the second field it gave a steady +36 reading with no tone in disc mode. Great, now what! I turned it off and on a couple times and still got the +36 reading no matter where I swung the coil. Hmmm.. I says to myself must be the ground is REALLY different here. Switching to all metal mode I coud hear every rock in the field as I passed over it and the Excel is normally immune to them. What the heck do I do now??? Thinking back on it I should have just went ahead an GB'd in all metal but being that I don't always think of the obvious I decided to switch to FP mode mstead which has always proven to be failsafe in the past. To make a long story short, the Excel worked fine after switching to FP, the constant +36 reading was gone and it ignored the hot rocks in all metal except for a few big/shallow ones. I went ahead and did the auto ground from FP mode she worked like a champ after that. Has anyone else experienced anything like this? do you think it was as I thought that the ground had changed so radically that it threw the Excels circuits off that far?

Now I gotta spend some more time out there and find me something "worthy" to post like you Easterners.

Tom

 

[BarnacleBill]

what I posted in Sept.

"Now this trip was the first time I had a problem GB

 

[Jackpine Savage]

I get that same response in PP. Instead of working normally I get a solid tone and the numbers climb up on the display like you are apporaching a large target even when you are not. I called a tech about this and he thought something was wrong. It hasn't happened in a long time so I kinda forgot about it I'll probably send it in to be checked out this winter if it starts doing it again but if the problem doesn't persist or repeat for the tech it would be a wasted trip.

This was different as there was no audio from the detector in disc mode even with the constant +36 reading on the display. It was when I switched to all metal that I got the response from all the rocks in the field. The first area I hunted has light colored soil areas where you get the 4 beeps when trying to GB. Move out of that area to darker colored soil and it balances fine with one beep. What I think happened was the GB setting from the first field was for very low mineral ground and after moving to the second field everything was seen as a positive response.

Tom

 

[BarnacleBill]

going to FP, then re-GBing fixes either scenario. Perhaps after the microP has slewed towards a GB limit there's not enuff time to re-establish a good GB before the Auto button is released. So not holding the coil to the ground and not keeping the Auto button initially pressed long enough may be a factor.

It may also be the microP has driven to a GB limit and is in essence stuck, thru a mathematical error. Going to FP should clear either condition, as the microP now has a known starting point which I assume equals Ferrite.

HH
BarnacleBill