Coaxial Coil

[Hobo]

Does anyone know if any mfg. besides Garrett has ever made offered a coaxial coil?

[Steve Herschbach]

For those that do not know coaxial coils are induction balance (VLF) coils that feature stacked transmit and receive coils.

This fantastic coil article by Carl Moreland mentions C & G Technology. I do think the Eliminator Loop by Applied Creativity / Jimmy Sierra for the 6.59 kHz White's is also a coaxial coil.

From http://www.whiteselectronics.net/calif/accessories_loops_.htm

"ELIMINATOR LOOP

Another special purpose Applied Creativity loop, designed to eliminate signal interference from 60 cycle transformers, high tension wires, radio frequency and other metal detectors. Because of its size, this six inch loop works great in high trash areas and easily matches the depth of 8 inch plus loops. In fact, in harsh environments it gets much greater depth than your standard loop because it has the ability to operate at a higher sensitivity level with less interference. It doesn't lose coins on edge and pin-pointing is a breeze. It's very sensitive to tiny targets and its ability to handle bad ground mineralization makes it a good prospecting loop. When used in the "all metal mode" this loop does not detect from the top of the coil, thus it can be used under metal fences and playground equipment. When you see it, don't be alarmed by the thickness. That's what makes it work! It is designed for use on White's Pro's, Eagles, Quantums & Spectrums. 

Eliminator Loop Item # JS-E6 $159.95  (currently unavailable)"

[Hobo]

Thanx Steve, Someone told me they thought Mine lab made one for the SD detectors, but I don't think so.

[Steve Herschbach]

Wrong technology. Coaxial coils are a VLF thing. For a Pulse Induction (PI) what you would be talking about is a figure 8 winding. These are made by Coiltek at least and were first called “salt” coils and then later “anti-interference coils” as they help both with salt ground as well as electrical interference. 

http://www.coiltek.com.au/coils/goldhunting-anti-interference/11-anti-interference-goldhunting/

The figure 8 winding causes the hi-lo audio signal to reverse front to rear and these coils are not as deep as other configurations, but will generally kill electrical interference dead. Perfect for working under power lines without using Cancel, which gives up even more depth.

[A-HEAVY-1]

Does anyone make a coaxial for a 7.69khz machine?