Big foot style for a PI

[Chet]

Hi Green

Thank you for another great test. Since the receiver coils will be inductively balanced you might be able to increase the number of turns to increase received signal strength. And earlier sampling may be possible.

Have another great day,
Chet

[green]

Want to make a big foot coil using two round coils and a race track coil. If it works I'll try a 3 to 1(length to width). Charted the coil responses to compare the big foot against when finished. Big foot (two Rx, opposite phase, One Tx around both Rx coils, IB)

[baum7154]

Yes the Racetrack 3:1 coil appears to have a very consistent blade of detection about 8"long and it is not difficult to pinpoint using one of the ends of the coil. I'll be posting more construction details and photos soon.

Regards

Dan

[Chet]

One difference between the Bigfoot figure 8 and your Racetrack coil is the field patterns. The Bigfoot coil has two sensitive detection points with a null in between. This makes it harder to pinpoint than with the Racetrack coil which has a pattern similar to an oval or elliptical shaped coil. Long narrow Bigfoot coils are popular with coin detectors for covering ground faster especially in competition hunts where the coins are planted shallow.

Regards,
Chet

[baum7154]

Thanks Chet. So from what I read a Bigfoot is a figure 8 coil.

[Chet]

Carl describes it here, http://www.geotech1.com/forums/showt...4905#post44905

Chet

[baum7154]

I'm unclear on what constitutes a BIG FOOT COIL. Is it applicable to a mono coil as well as a DD coil? Is it just any coil with two parallel sides and either rounded ends or square ends in a 3:1 or 4:1 length to width ratio? Does it look like the coil in post 216 of the CHANCE PI COIL thread of the COILS forum?

Thanks,

Dan

[punagold]

Mohandes,

I can't explain, I'm just trying to make a coil for my Garrett ATX, which comes stock with a DD coil.

[mohandes]

how use DD coil for pi machine?
can explain?

[Carl-NC]

Yes, a Bigfoot-style PI coil should also cancel Earth field.

[punagold]

Not exactly bigfoot, but I'm trying big. Had it working this morning, now dead.

[kt315]

do not keen foot style and oval coils in PI. those coils has sharply low sens be cause the form.
1/3 sizes of diameters is too critical. may be 2/3 still good. I do not remember who wrote about that. so believe me now on words.

Anatloy

[green]

I read where it cancels noise and can reject ground. Would it also cancel earth field?