High pitched Empty sound on F 70

[Waterdog]

I went out to a couple of places today. At a couple of the locations I went to I was getting High pitched empty sounding signals. When I tried to Pin point them I could not find them. Has anyone else had anything similar happen?
Thanks in Advance

 

[Phil]

The hot rocks I ran into field hunting hit high VDI numbers and pinpointed really weird. Sometimes the pinpoint tone would just vanish over the target and other time it would sound strange.

 

[tony (Orlando FL)]

Still not 100% sure of exactly what it is, but know in most cases its junk, YET I dont want to take the chance and pass it by either...

Kinda glad you are hearing it too.Click here to see previous post on this

 

[detectorbill]

I know exactly what you mean, in my mind I call them the transparent highs. They have a high pitch but you know it's not the "real" high tone, you can see through them. I had the "tone" today and dug to see if I could learn what the F70 was trying to tell me. It was a small square nail (1 1/2" long) at around 6" . That's pretty impressive depth on that small nail but I was set at 16 disc. in DE mode 80 sen. and 0 on the TH. My next thought was to return to 0 disc in DE mode at the same sen. and TH. to see if the next nail would provide the typical grunt for iron. To my amazement I received the "transparent" high signal again but this time I did the 90 degree and it grunted like a pig in that direction. I have used several detectors and I have experienced this phenomenon before so I truly made a effort to see what this machine was trying to tell me. I dug (4) 22 cal. bullets, (12)
small square nails and (1) large square nail. The next signal was a bit different: I got the "transparent" signal in one direction and at 90 degrees to that got a true high signal so I dug with enthusiasm to see what this would be and it was a 1947 rosie and a square nail within the same plug. I wonder if the "see through ability" they hype is actually the reason the "transparent" signal to even exist? I believe this detector will be a winner but we need the input of all the users to make all the nuisances and quirks known!