As you know, the red dirt areas are pretty tough for any VLF detector to handle. As previously stated, I've hunted in the GA red clay as far south as Marietta, GA. I've hunted as far north in the red iron dirt of Culpeper County, VA. And I live here in TN where we have a mixture of the GA red clay and iron dirt of VA.
Let me give a break down for what is going on. The ground itself has a heavy iron oxide to it; thus the reddish color. Some is worse than the others. For anybody that has never detected in it before, let me give you an analogy of it. Say you have a good size piece of rusty tin from a roof. Now throw a coin down on the ground and cover it with the tin, and try to take your detector to knock out the tin and still detect the coin. Well that's a little far fetched but it gives you a good idea what this dirt is really like.
Basically the shallower items in the ground, can be hit pretty good with VLFs. I've found the cut off limit to be about 5 inches deep. Most VLFs can do pretty good down to that...but its that point and beyond that things start to get tricky. The exception is VA in which I've actually had Civil War bullets in my dirt pile still read as iron with just that little of dirt covering them. What is happening is, the detector is functioning as it is suppose to. If you are running in disc mode and have it set above iron...that's where the bad stuff starts happening. The detector sees EVERYTHING in the ground as iron itself; so it is knocking it out and you're walking over stuff and never even knowing its down there. Stuff that is well within reach of your detector's search loop.
So here is the kicker...all metal mode will open this up. You will hear the signal but on an ID machine, it is going to still read as iron FOR THE MOST PART. The problem then becomes, trying to discriminate with your ears. There are very few VLF machines that can handle the red dirt. The V3 is one of them. Of all the VLFs I have hunted with, the V3 is actually at the top of the list for those that CAN handle it and do a good job at it.
The problem is, you have to get away from the factory settings and tweak a little. Here is what I did to open it up and help out quite a bit:
I'm a relic hunter so this one is for the relic guys but I found a little modification that can work for you coin guys too. So for starters, the preset Relic mode is a good place to start. Then, as before stated, put your Search Audio in All Metal mode via Expert menu. Then you can up your All Metal sensitivity/gain to where ever the unit is stable at. The next thing you're gonna want to do is put it in single frequency mode. I have played around with this quite a bit and for coins and relics, I found the single frequency of 7.5 to give the best target response. I honestly never played with the filter settings. Put it in manual ground balance; I don't like auto tracking. These where my primary adjustments though. The next big thing I done was to change the Recovery speed rate to a setting of 40. Here is why:
Since you are using All Metal to locate your targets, most everything is going to sound the same....including iron that is in the ground. As a relic hunter, some iron CAN be good, but for the most part we don't want to dig it. Especially square nails. So what the recovery rate of 40 does, is speeds it up quite a bit to where it is VERY easy to distinguish a nail from the very fast double blip it will do. It's a big give away on nails. You'll still dig some that are bent but you'll do that with PI machines too. That in itself will help a ton. Now the neat thing I REALLY liked about the V3, and that separated it from the other VLFs, was that Whites done a very good job of giving a feature that sort of "averages" out the signal.
I noticed when I'd get a good solid sounding signal that didn't double blip...that if you swung the coil over it multiple times sizing it up, that the detector would average it out. I was actually doing very well digging Civil War bullets down to about 11-12 inches that would actually occasionally show up on the ID meter as a bullet. 70% of the time it still read as iron but it would bounce up there into its normal range from time to time. Then once you got it out of the hole, it would read as normal. This held true even up in VA.
Now in some cases and places, your ears aren't going to be able to handle the All Metal audio. What you can do there is sort of experiment around a bit. If you have a test garden you can do it really good, other wise it is going to be hard. What I'm referring to, is to keep it in Disc mode but go and open up most all of the iron range. It has been about a year since I've had a V3 in my hands for a while but I do remember there was a certain range that bullets/buttons/coins seem to fall in, inside of the iron range. I would open up to that point and hunt til I got a signal, then use the fast menu thing to jump into all metal and size up the signal real good. It kept the machine a lot quieter than All Metal but I would still use All Metal to size up a target and see if I wanted to dig it or not.
Here is a video I done back when I had the V3 and me digging some bullets. You can get an idea of the audio of a bullet and such. I had fun this day...it was the day I discovered how to open it up beyond factory settings.
http://www.youtube.com/watch?v=Bx7qJ4K0sK0
I had to sell my V3 to buy tires for my truck but if I had the money to buy any VLF on the market today, the V3i would be it hands down. Now, if you really want the depth, you can hop to a PI machine. That's what I have done and a PI will handle the red dirt far better than the VLFs. But as far as VLFs go, in my opinion, the V3/V3i are #1.
