Anyone have Surf PI Pro Schematic?

[golfnut]

list of questions - pls reply even if your not certain...




surf pi coil - whats the popular average design ....?
ans...

with said coil an air test will be approx 28cm on a midsize coin ---

what depth would this be in average uk soil...?
ans..


and same question in wet sand (not black)?
ans...

any mods on the surf to put in - from the off..?
ans...


If anyone interested I can measure the fields on a loop antenna in 3D and post.

[TH Jim]

The surf pi is quite forgiving in its coil specs. I have tried everything from 20 to 30 turns between 8 and 10 inches.

I have now settled on:
21 turns
0.4 mm enamelled copper magnet wire
9.75 inches
Mylar shield

Using:
IRF9460
390 ohm damping


Thats just my preference, despite what the purists might say - in reality a turn or two here or an inche more or less there has very little affect on performance.

Hope this helps,

Regards Jim.

[TH Jim]

P.S

The above also works well on the Barracuda!!!

Cheers,.

[Comp]

Ok guys, all the bits are here, and assembled, (Thanks, Andy, you're a star!!) Using the 2 coils I have wound, (they both perform about the same,,,,) In air, I get a signal from a 1P coin at about 4 inches, a 2P coin, and my wedding ring, at approx 6 inches, an aerosol paint can at 10 inches, and a 'Quality Street' sweet tin lid at 13 to 14 inches.
As this is my first MD, and first build, come on you Surf longboard builders, gimme a clue, am I in the ballpark, or have I still got some work to do??? It doesn't seem very deep to me, but I dont know how the board performs??? Tell me what yours does, please!!!

I have one simple 21 turn, 20cm 22 swg enamelled copper wire coil, approx 350 microhenries, and the other is 'basketweave', same diameter, 24 swg, 330 microhenries, as per photo earlier this post, and as I say, both perform roughly similar. I have powered the board with both an 11.1V Lipo, and a 12v 4AH sealed lead/acid cell.

Cheers, thanks in advance for any of your data, Fred

[TH Jim]

Not bad for starters - at least it works! But it should be able to do better than that. Look for at least 10 inches minimum on the 2p coin. Also check whether your 1p and 2p's are pre 1992 - solid copper or post 1992 - copper plated steel. the Surf PI loves that iron and will give better detection depths!

Good luck

Jim.

[TH Jim]

Back to the topic of the thread;

Does anyone know where the gain pot on the SP pro is connected?

Anyone have a guess - NE5534 or LM358 ?????

Regards Jim.