No icon or vdi on weak signal

Kenkoehn1950

Jr. Member
Jan 18, 2013
94
71
Denver, Colorado
Detector(s) used
Spectrum XLT, ATPro
Primary Interest:
Metal Detecting
I have started running without audio discrimination on my Spectrum XLT to get more depth. Today, I actually got really faint signals and after pin-pointing, I determined the depth to be anywhere from 9-12" on several different signals. I did not dig as the ground was quite hard past 5-6". My question is, with no VDI or icon, how do I know it is worth digging?
 

In a park, I would say no. Your machine is probably hitting a pipe. There is no bigger drag than digging 7-9 inches down to hit a stinking pipe. If you are in a gold field, then you must dig all targets.
 

Great point made by JC. I might suggest digging down a few inches and running the coil over the target again and see if you get a better tone or VDI reading.
 

Most, if not all, detectors will give an audible signal on targets a fair bit deeper than they can register a tid reading. In an area where there is a good chance of old silver and/or no problem digging deep, then I'd go for it even though I might be digging a fair amount of trash.
luvsdux
 

beez0404's suggestion is a good one. Take a bit off the top and see if the machine will give you a clue. If were your digging has pulled up some interesting items at depth its worth a shot. You can also try re-balancing your machine and sweeping again... sometimes mineralization will give a similar indication.
 

Actually, I think you are a glutton for punishment! You have a detector that has great capabilities of IDing a target and you turn them off. That just plain doesn't make sense. If you are doing parks, the coins and jewelry program will find targets as deep as you want to dig in a park.
If there is a pipe there it is easy to tell because you will get a long signal path tracked out. You have a great detector, but learn it's potentials. Frank...
111-1 profile.jpg
 

When in doubt dig that fu@#er out! Could just be a small piece of iron with a lot of rusty fluff on it. They tend to sound deeper than what they are. I run a Tejon in audible all-metal on many of my sites. After a while you get a pretty good idea of the size, density and depth of a target just by sound alone using vco turned on. It wouldn't hurt to dig it up just to see what it is and make a mental note how your detector reacted to it.


-Swartzie
 

I sort of agree, but with a few stipulations.

Once you get used to a no discrimination mode (took me over 20 hours at least), you start getting a sense of what you've located. If you don't believe that, ask anyone who has used a PI machine for a few months.

I can't speak of other brands, but I've been using my GTI-2500 in All-Metal mode for the last several months. I've gotten good enough at it, that I can determine a coin about 25% to 30% of the time. I doubt anyone can get any better due to the limitations of no discrimination.

One thing is for sure, you do turn up a lot more trash! But sometimes, not often, but just once in a while, what you dig will put a smile on your face for a very long time! Like my $5 gold piece in VG condition!
 

reason targets within a detectors depth range are missed is a result of poor technique. Swinging too fast, leaving gaps between swings and lifting the coil at each end of a swing are some of the reasons, and we're all guilty of doing it at times. The search pattern of an eight inch concentric coil at 7 inches deep probably doesn't cover much over a two inch circle, if that much, and overlapping the width of the coil would leave at least a 5 to 6 inch gap the detector won't see at that depth. Use a slower swing and overlap less............end_of_your_arm.jpg
 

I have started running without audio discrimination on my Spectrum XLT to get more depth. Today, I actually got really faint signals and after pin-pointing, I determined the depth to be anywhere from 9-12" on several different signals. I did not dig as the ground was quite hard past 5-6". My question is, with no VDI or icon, how do I know it is worth digging?
DO NOT DIG THOSE TARGETS!! Mark them and then let me know where they are. :)
 

empty_pockets,
While those are fair reasons for missing or not being able to find items at depth they really don't account much for the question as to why one would not receive a VDI indication or have a weak target response. Being fair about it I would guess all of us have had similar situations on iffy targets. Making adjustments to our wands, sweep speeds and overlap or just plain digging it are what I consider typical courses of action. For weak targets typically the reason for intermittent signals and/or lack of VDI can usually be one of my top 3 reasons : Depth verses size of target, Balance of the machine and mineralization *a form of masking*, and masking due to other conductive items nearby or emi.
VDI operates in the discrimination circuits and is coupled with signal processing to give one the best "Guess" as to what's in the ground. As such VDI has a cutout threshold to where it makes its best guess on a target. If a target is being affected by one of my 3 reasons VDI on such a target may simply not work or be very intermittent and jumpy.
Weak target response is just that. One messes around a lot with targets like this and I know I'm guilty of tweeking just to see if I can enhance my hunt. But in the end if I just cant get what I want I'll dig it or just knock some soil off the top and see what my wand tells me.... then decide whether its probably a dry hole and move on. I probably miss some goodies this way, well I know I do, however its all in how I want to scratch the itch of my curiousity. Nothing saying I wont come back to the target again :) with another wand or just to dig it.
 

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