LovestheShiny!: said:
Monte... question - how much additional depth do you think the 8.5 X 11 would have over the stock Viper coil? Thank you!
A good question deserves a good answer, so I'll give mine. No magic mystery percentages that are not calculable, like some imaginary 12% better separation or something similar, because in this real world of metal detectors and metal detecting there are just too many variables involved.
Ground mineral composition. Ground material make-up, ground density, porosity, and the variance from dry to damp to wet to saturated conditions. Target size, shape, metal alloy make-up and orientation in the ground. Search coil presentation to the target and search coil sweep speed. Settings used, especially those regarding Sensitivity, Discrimination, Ground Balance and operating Frequency.
Now, with all that to consider, I also consider this ... I am not a big fan of 'Depth' topics I so often read about. I have been present many times when a recovery has been made by an individual and I observe the recovery process and the located target's depth and orientation to the search coil. Then I hear a comment made by the finder of the target who describes how deep it was ..... but it really wasn't. Rarely, but occasionally, they under-guess the target's depth. Most of the time it exceeds the actual located depth, and for several reasons.
I'm not into 'depth' so much because with over 55 years of very avid detecting I have found a few truly deep coin-size targets, but very few. Coins don't sink, and unless there is some sort of activity, such as mowed grass, fallen leaves, digging, tilling, plowing, or some sort of vehicle, human or animal foot traffic to help cause
disturbance and displacement, lost coins and similar objects are not going to be all that deep.
In the real world, and caused by natural occurrences or acts of nature
(floods, erosion, tree and vegetation growth and decay, etc.) the bulk of the lost targets we are after are going to be located from surface to about 4". Those that are an honest 4" to 6" would be a mid-depth target, and the majority of the so-called 'deep' finds are in the over 6" to perhaps 8" or 9" depths. On rare occasions are they going to be deeper. They might be now and then, but those are the rare finds.
So, lets get to search coils. The standard 'Viper' measures 6X11 and is a Double-D design. The new 'Raider' coil that is announced is based on Garrett's proven 8½X11 coil. So the front-to-rear coverage isn't enhanced because both coils are 11". But the increased width of the coil will enhance the detection depth. Partly due to the wider diameter of both the Transmit and Receive windings, and a bit more overlap of the two windings down the center of the coil, tip-to-tail.
The length is the same, and the new coil's width is about 41.666% or 41⅔% wider, but that is a measured amount. When it comes to anticipated depth increase over the 'Viper' coil, without having one in-hand yet or used afield, my typical 'best guess' would be an increase of anywhere from ½" to 2" depending upon the size of the coin.
The other reasons I am not into 'depth' is because so many posters are relating their wishes for increased depth when looking for smaller-size targets. Ideally, smaller-size to mid-size search coils are the best considerations for finding smaller-size targets. Larger-size search coils are more intended for finding larger-size targets.
Big belt buckles, knives, axes, firearms, helmets, spurs, or perhaps bags, bottles, cans or boxes that contain large amounts of metal. A Cache Hunter might appreciate a bigger-size coil, and in the earlier days of ground-cancelling detectors the devoted Relic Hunters enjoyed bigger coils because they were usually looking for bigger-size artifacts.
A lot will depend on the types of sites a person hunts and the challenges they face. For me and where I typically search, I am confronted with a lot of debris, especially ferrous-based junk. There are too many targets that are too close to be able to expect any opportunity for improved depth. It's tough enough just trying to find and isolate a keeper in all the debris. Smaller or occasionally mid-size coils are the better choices.
But I live in a small rural town and we're surrounded by rangeland, pastureland and farmland. There once were old cabins, ranch-hand sites, bunkhouses, barns, schools, churches, migrant worker sites and dance halls scattered about country in what is now wide-open grazing land or cultivated farm land.
'Cultivated' is the key word here because all that activity over decades of time has churned things down and back up countless times so lost targets can be shallow, mid-depth or deep and the areas are wide-open and a lot of ground to cover. The 'Raider' on an Apex should help with coverage, but also add that needed ½" to 2" detection depth that might come in handy. For smaller-size targets I do not expect to gain more than 2", if that. But when the opportunity is there, and the conditions are favorable due to fewer targets to impede performance, any little 'edge' can make for a good day.
Monte