There are few things a water hunter needs to be happy when doing his work...
A good bottom condition and a well prepared machine to do the job.
Many times I found good stuff but really struggling with a coil larger than 10".
Vlf or pulse, will depend for the most by the environment type, but talking about coils, there's no comparison for a diver with an 8".Not only saltwater is a reduced problem with it, but between rocks, between waves,between any other thing, I still prefer to use a smaller coil.
I'm in love with the AQ performance, for what I can see in multiple videos Joe OBN is publishing, but I only think about a smaller coil to be released soon.
I hope Alexandre+FT are already working on this thing, cause otherwise I'll be forced to wait until that moment will be reality.
8" coil is a rule for me.
I just happened across this video and thought I'd post it.
I still find any of these simple videos to not include 'off the coil' sensing of a target. They show field restricted to just the edges of the coil. We all know the field is larger than the coil. I say I'm drawn to some of my targets like a moth to a flame. Some days I am better at this than others.
It's the FRINGE that can make a difference.
By Steve Herschbach
VLF detectors can come with DD or concentric coils. This is similar to but not quite the same thing as DD versus mono on a pulse induction detector. There are three basic coil types in wide use, Concentric, Double D (DD) and Mono. A VLY detector transmits and receives simultaneously and so there must be both a transmit coil and a receive coil. A pulse induction (PI) detector can alternate between transmit and receive and so one coil can be employed as both transmit and receive in an alternating fashion. There is confusion on this but simply put VLF (induction balance or continuous wave) detectors do not employ mono coils. A VLF can only employ the concentric or DD options. A pulse induction coil can work with all three types.
Metal detector coil types illustrated - concentric vs DD vs mono
VLF detectors are more alike than different these days. One thing that can make a real difference is what coil the detector comes with. Two very similar models will be quite different if one comes with a 12" round concentric, and another an 11" x 7" DD.
In this case the very same detector can be turned into two different detectors by changing coils. Here are a couple rarely seen on the F75 - the 10" x 5" DD and 10" elliptical concentric. A big difference between the Teknetics T2 and Fisher F75 was that the F75 came later and the ability to use concentric coils was added. The T2 can only use DD coils.
Why DD or concentric? DD coils are all the rage these days. However, concentrics have more consistent detection patterns with less dead spots up close. Every notice how that DD coil goes wacky on shallow targets? And concentric coils are much better at identifying flat ferrous targets like bottle caps. Here it is from the guy that should know best, Dave Johnson, lead designer on the F75.
About Search Coils by Dave Johnson
Search Coil Field Shape by Dave Johnson
Coil Basics by Carl Moreland
I like the 10" DD for the solid design, better for working in stubble or other locations where an open coil might hang up. The concentric just for being better behaved. The DD is the better prospecting coil for bad ground. Concentrics do well on milder ground.
A note on coils. The blade like knife edged detecting pattern depicted in DD marketing ads is largely myth. Electromagnetic fields radiate and simple coils cannot focus them into beams. A round concentric coil has a search field shaped like a soccer ball cut in half. A similar size DD coil will have a search field more like a football cut in half lengthwise. If you ever doubt this, just fire up your detector with a DD coil, flip it over, and run a coin under the coil noting where the signal fades at different locations under the coil.
Finally, depth is more related to coil width than coil length. Think of a 5" x 10" coil as a stretched out 5" coil, not as a skinny 10" coil. That is why when listing elliptical coil sizes you will often see me putting the small number first. Marketers do it the other way around so you tend to think you are getting more than you are. A truer picture can be had by comparing the total area of a coil, one to the other, but for quick and dirty comparisons, comparing by width will give you a more conservative idea of comparative coil performance, than comparing by length.
Fisher F75 with 10" Elliptical DD Coil
Fisher F75 with 10" Elliptical Concentric Coil
Hi all, can anyone advise if the Coil cable attachment to the SDC is the same as GPX 5 pin standard? I noticed that Coiltec have a accessory pack to adapt to the SDC 2300 shaft then use a Coiltec coil instead of the supplied unit.
I have old coils that I would like to try out.
Wondering what effect using another manufacturers coil would do to the product warranty also, cheers sturt
I figured I should post this here as I posted the information elsewhere on the forum that's less relevant than here.
Our extremely innovative Russian friends have managed to make a range of aftermarket coils for the Equinox, they remove the security chip out of your coil, reseal your coil and give you an adapter which then allows you to run aftermarket coils. They make a range of sizes too. My pick of the bunch would be the 9.5x5.5!
That's the range of sizes and pricing in Russian currency.
You can find out more about it here on these Russian forums, you'll have to use Google translate or something similar to read it.
And videos from them about the coils
and lucky last 🙂
When nobody can do it, the Russians do and they do it well.