It seems like for the past too many years, especially the past fourteen or so, there has been more and more talk about Double-D search coils. We were aware of them in the early to mid '70s when Compass used DD coils in their straight TR's and Garrett also had them in some TR's. We could buy a detector with a "Wide-Scan" coil [size=small](Double-D)[/size] or some other type of search coil, but most folks didn't really seem to pay much attention to the search coil design back then. If a detector looked good, the hype made it sound good, and it worked for you, that was fine.
When TR's had Discrimination added, most manufacturers went away from the DD design because they didn't work too well when it came to discrimination. They especially had more difficulty dealing with iron rejection. Add to that the growth in the hobby of Coin Hunting and many people had a bit of difficulty pinpointing a target with a Double-D coil compared to any of the more 'traditional' designs that were used.
Then the mid-to-late '80s we saw a start in the growth of more gold nugget based models and some, not all, came with or offered a Double-D search coil. They were still a little helpful for coverage with nugget-shooting detectors because they operated in the Threshold-based All Metal mode and most models didn't have a Discriminate mode, be it a traditional TR-Disc. or a newer motion-based VLF-Disc. design. Most manufacturers still made Concentric type search coils and most models still came with them.
The it was about fourteen years ago when Minelab Explorers hit the scene, all with Double-D search coils, and I think it was about that time when some manufacturers felt a need to swing their production more towards competing with those higher-dollar FBS models and we saw more and more brands produce Double-D accessory coils or make new models that came standard with DD's. Okay, fine if they want to, but I feel more makes ought to offer the detectors with a door range of Concentric search coils to choose from.
Also, we have quite a few higher-frequency modern detectors that are designed to ONLY work with DD's and many do not even have a Concentric search coil made for them. Models like the Fisher Gold Bug Pro series, Teknetics G2 and T2, Fisher's upper-end models, and now the Fisher F19's. There are more foreign-made competitors, too, who do not offer a Concentric search coil.
My old Compass Coin Hustler and 96B TR's have Double-D search coils [size=small](6" and 8" in that order)[/size], and my sub-5" round Teknetics coil is a Double-D design as well. Those are the ONLY DD's I have in my personal detector and coil inventory. Everything else is a round-shaped, Concentric type search coil. My next Teknetics Omega will come with an elliptical 5½X9 (they call it a 10"" Concentric coil, but while I DO like that coil for some more open area searches, I'll likely sell or trade it for another round 8" Concentric coil.
Reading this thread is refreshing to me because I tend to harp on Concentric coils more often, or I guess you could say I state my lack of interest in the DD coils, that it's good to read other thoughts on search coil selection. I have a back-pack detector bag that I use exclusively for my extra search coil on lower rods. It travels with me all the time and holds my 12" Concentric for the MXT All-Pro, back-up 6½" and 9" spider Concentric coils for my MXT All-Pro and MX5 [size=small](I have one each currently mounted to these two models and can switch to the other from by coil bag)[/size]. An 8" Concentric for my Bandido II µMAX on which I keep a 7" Concentric mounted. A 6½" Concentric for my Classic ID which I have a 4½" Concentric mounted up.
For many decades I have preferred smaller-than-stock search coils because they work best for me in the trashier/brushier locations I prefer to hunt. On an Omega my two coil picks are the 8" Concentric and sub-5" DD.
Ivan said:
Wow I thought I was alone on this one or just imagining it. Didn't know that you were a fan of the 8" round as well. Now up in our circles here... there are guys giving the Concentric 8 another look. Really helped to have you back me up on this one. Thanx
Ivan, I am a fan of any GOOD Concentric coil. Unfortunately, Teknetics doesn't make a 5" Concentric coil for their Greek series or that would be in my arsenal and likely used the most. They don't so I prefer the smallest Concentric, the 8", and use the little 5" DD for trashier conditions, if the Omega is in-hand. More people ought to give the 8" Concentric a try on their Greek Series models. For me, the field performance has been quite satisfactory!
cal said:
While I like the nels sharpshooter and the elliptical coil that comes with the Omega, the 8 inch seems to perform deeper and sound clearer like you said. It is much easier to pinpoint with than the stock coil for sure. I run my omega mostly with the 8 inch coil and the nels sharpshooter on my Gamma. I like the Omega very well and run a lot with the settings on disc 1 with tones d3. I also run a lot in the AT mode with the tones on A2. My soil is very mild around here, usually in the high 50's. many of the haul in sand places will run 76 to 78. As far as sensitivity settings as high as the law will allow. My Omega is a version 4 model. Good luck with your machine.CG
cal, I also like the elliptical Concentric stock coil with the Omega, I just happen to like the round 8" Concentric coil better, and have since mid-2012. As you noted, I get a little better depth, cleaner audio response, especially in trashier environments, and quicker target pinpointing with the 8" than the stock elliptical coil.
My 'average' soil conditions have a Ground Phase read-out from about '73' to '79' but I get into a lot of places when it runs in the '81' to '85' range, and occasionally I find a place where Ground Phase read-out is in the low-to-mid 50's.
Give me a decent working detector with a good Concentric coil mounted and I am a happy fellow. We should all make the choices that satisfy us, even if it's not somebody else's pick.
Monte