Broken rings and chains

[nagov]

I'm fairly new to the CTX and just getting into seeing what all the adjustments can do for you with this machine. I primarily beach and water hunt and will be using the CTX for this purpose most of the time. This morning I decided to do some testing in the yard with an assortment of rings and a medium gold chain just to see what the CTX could do for me. All of the rings rang out like I thought until I got to a 10k broken claddagh ring I got last week with the Excal. This broken ring almost never sounded off with a tone until I had the coil almost on the ring and doing the Minelab wiggle on it. What I did notice though (which I thought odd) was that the Threshold blanked over the ring about 95% of the time. That I thought was interesting so I tried the chain both straight and balled up and came up with again almost the same results as the broken ring! I then changed search modes from Beach to Relic and found the detector sounded off more often on the ring and chain in that mode... it didn't do give a tone 100% of the time but more like 75% of the time with the coil height above the targets about 2 inches.. A slower and shorter swing of the coil did make a difference in the repeatability of the target response.

So, now even though I don't hear a tone but hear the threshold break and it is repeatable, its time to locate the target (threshold break), make slow small swings to almost pinpoint the target (Minelab wiggle), then either dig and investigate or switch modes to give me more information about what may be down there... this is a very interesting machine.....
As a side note, I thought maybe I had my Threshold volume to high and that was causing the blanking of the targets, I did further testing and what I found was the Threshold volume didn

 

[stitchlips]

Just curious, did you bury the target when you did this? I have found one really small 10k chain that was hair thin and two very small 10k rings. The rings were not broken though. I did find one nice 14k earring that did not form a closed loop.

 

[nagov]

No, these were tested just laying on the grass. I know it is far from a scientific test but it will have to suffice until I get to the beach tonight and do some in the sand testing.

Cliff

 

[stitchlips]

No, these were tested just laying on the grass. I know it is far from a scientific test but it will have to suffice until I get to the beach tonight and do some in the sand testing.

Cliff

I did the same thing. The CTX performs very poorly with just air between the targets and the coil.

I have noticed a blank threshold several times while beach hunting even with no disc on. I think I will start to dig these targets up.

 

[ikspeel]

Have you. Try it on the beach

 

[Johnnyanglo]

A gold chain produces tiny eddy currents that quickly die away - that is, there is high resistance or low conductivity. A ring with a break cannot produce the larger eddy circulation and forms smaller eddies on the ring surface. The net effect of both cases is a very weak, short-lived resistive response to the receive coil. Since the FBS system looks at the time constant measured at two freqs it is hard for the detector to see low conductors. In fact, that is one strength of the CTX and E-Trac, they react poorly to iron (a high resistance target). So, the upshot is, FBS often 'sees' small, low conductors as if it were iron and nulls it out or barely detects it at any distance. A detector with a higher op freq will zap the low conductors harder and thereby invigorate the eddies resulting in a better secondary magnetic field and better sensitivity.