TDI SL Coil For The Beach ?

[Mark Gillespie]

The 12" dual field is by far the deepest coil I've used on my TDI but the heaviest too.  Amazingly the Super Pulse 350 and the 7 1/2 Dual field have about the same depth capabilities.  If you don't mind digging deep holes at the beach the 12" is super. 

But more importantly is hunting areas where the sand is not more than 12" over top of the hard shell pan areas of the beach. 

Look for areas where the sand has washed out small gullies. 

If you're hunting in the very wet sand area where you actually start sinking while standing still, that might not be the best area especially if the hard pan area is 2' down (the heavy gold items will sink until they hit something to rest on).  There is a lot to be said about these two areas.

Hope to take my TDI back to the beach this year.  Gold, here I come.

 

 

[GB_Amateur]

One thing I've noticed (but it seems to be controversial here) is that when I ran my 12" mono on the TDI SPP (nominally an SL) without ground balance it detected considerably deeper (in an air test) than with GB on.

Here is a very good in-ground study done a couple years ago in Australia (probably mineralized ground):

https://www.prospectingaustralia.com.au/forum/viewtopic.php?id=21209

Don't miss the second page which has tests with the larger coils.

[Mark Gillespie]

1 hour ago, GB_Amateur said:

One thing I've noticed (but it seems to be controversial here) is that when I ran my 12" mono on the TDI SPP (nominally an SL) without ground balance it detected considerably deeper (in an air test) than with GB on.

Here is a very good in-ground study done a couple years ago in Australia (probably mineralized ground):

https://www.prospectingaustralia.com.au/forum/viewtopic.php?id=21209

Don't miss the second page which has tests with the larger coils.

Yes, you are correct, GB off is deeper and that is the option I take at the beach.

 

[Rivers rat]

I got one you may be interested.........it is hand made and designed by the originator of the Impulse....

 

 

 

RR

[Jim in Idaho]

In all the testing I've done, I got the deepest results, regardless of coil used, or battery voltage, with GB on. Just saying.

Jim.

[FWest]

Thanks for the input Mark, Jim and GB. I have done a bit of air testing with the stock coil, 8 to 10 inches depending on the items (coins mostly). The ground balance did not seem to make much of a difference in the air. I did hit the beach a couple more times after asking about a coil and found a few junk jewelry items and some clad. I have spent many hours reading about the tdi sl, tdi pro and available coils OE and aftermarket. 

Since then we are defrosted and I'm back in the dirt/mud and my go to is an eq600. I do intend on trying my TDI in certain areas after checking them out for junk first. I do cruise most of the popular forums looking at the FS areas thinking I might stumble across a fair deal on another coil. 

River rat, pm if you want and give some details, assuming you were speaking to me.

Thanks, FWest 

[Ridge Runner]

FWest

Sometime back I bought a dual field coil from a guy on here. I had what looked like one but it’s nothing in the center coil. Now if you would like to have that coil and willing just pay postage it’s yours.

PM me your address and I’ll get it to you. You can see what it cost to ship when you get it and then mail me back that amount.

Chuck

[GB_Amateur]

20 hours ago, Jim in Idaho said:

In all the testing I've done, I got the deepest results, regardless of coil used, or battery voltage, with GB on.

Were those tests in-ground or in-air?  I'm figuring your ground is much more mineralized than mine. 

Seems like there are a lot of different results with/without GB on the TDI/SL.  In my case I was trying to find a buried shotgun for a friend.  He had a heavy gun barrel which I used as a test piece.  I actually laid it on the ground (so not a pure air test) and raised the coil.  With GB on I could only get a couple feet or so above the barrel.  With GB off it was well above my waist -- maybe 4 feet -- and I was still getting a signal.  Again, I was using the White's 12" mono coil.  I don't remember if I was running 12 V (more likely) or 16 V.

I suppose it's possible that the circuitry varies among SLs, but that would seem odd for factory units (i.e. without Reg's garage mods).  Although mine is not an SL but actually an SPP, supposedely the difference is simply a delay time locked at 10 microseconds and the conductivity switch locked in 'all'.