Cibola falsing from rocks?

[pamlicopanther]

I was out with my Cibola today and started having a problem. When I hit certain sections I would start getting false signals and my detector became very unstable. I would hit these sections and then go to other areas and it would work fine. After going over several of these sites I realized it was falsing when I hit sections of rock (granite rock I believe). It did fine on other rocks, but when exposed to this particular kind of rock it went crazy.

Has anyone else ever had this happen? I hope it isn't a problem with my machine.

Thanks.

 

[Furious T]

It sounds as if your machine is fine...there are certain rocks (and certain mineralised soil) which does affect a detector. Gold prospectors pay the money for their machines that they do to try to counteract such conditions. The rocks are often referred to as "hot rocks" and you can encounter them in all sorts of places. They are rocks which usually contain a concentration of iron, and so affect a metal detector. It sounds as if the location in which you were detecting has highly mineralised soil, so the only thing you can do about it with the Cibola is to detect in another area, or persevere with the mineralisation. Chances are, where the heavy mineralisation occurs, you wont get very good depth with the Cibola.

 

[Reddog777]

I had the same problem with my Ci-bola and they were granite rocks also. After a while, I learned to ignore them because the signals they gave were longer and broken more like a 3 tone signal. Not solid like a good target. But if you are just using your Cibola, dig every target for a while so that you can associate the difference tones with the targets.

 

[pamlicopanther]

Thanks fro the replies.

Where I live (eastern NC) we do not have rocks naturally. These are actually rocks that are brought in for driveways. Funny thing is I have detected this area for around 5 years using this Cibola and haven't had this happen before. I have not been in this exact area before, so I guess I never hit this particular rock.

 

[Reddog777]

I in live NC also and these granite rocks were on Wrighstville Beach. Very unusally and annoying.

 

[Monkeywrangler22]

My old Cib used to false on granite used as the base layer in tot lots at some parks here in the DFW metromess. It's because of the iron content in the granite. Some will stick to a magnet.

 

[pamlicopanther]

Your not too far from me (near Washington).

Anyway, I am surprised I haven't had this happen before as I see these rocks around all the time.

 

[pamlicopanther]

I wondered if there was some iron content in those. What I don't understand is why I can't adjust the disc to make it stop.