Litz Wire Coil

[dbanner]

In my very limited experience building coils for pi, the flat spiral wound coil gave best results especially on small gold. All the basket type coils i made were very disappointing, especially considering the time it takes to make one of these. But that is just my experience.

[dbanner]

Could you post some pics of your coil

[James]

I got the Litz wire and had a chance to wind it on 20.5 CM coil form. I used card board, until the FR4 material comes in. The results are as follows, a gold ring was test is 21CM. I used a piece of aluminum foil 21CM it was found at plus 46 CM. I tire to shield the coil it DIDN'T work at all. Well that is my results of my basic test. Best to all Jim

[6666]

Good question Joseph, I would also be interested in what Sean calls a flat basket weave as there are many interpretations of coil design.

[WM6]

http://www.geotech1.com/forums/showthread.php?23838-DIY-Mad-Litz-Wire-for-ULTRA-FAST-PI-Coils

[bbsailor]

Then use thicker wire. The lower the series resistance, the higher your Q will be, of course then you run back into the interwinding capacitance problem. Always a trade off isn't there ;-)

If you space out the coil using a flat basket weave and wind 100Lbs FLOUROCARBON fishing line as an inter winding spacer then you will made a VERY fast High Q coil. If you are using a dual coil, wind the RX coil PARALLEL to the TX coil i.e. side by side in a FLAT format and you will have the lowest capacitance, fastest coil possible. I managed a 2.5us sampling time on a Surfmaster PI coil using this method, it's simply DYNAMITE on small gold.

Sean,

Could you please share some technical details of your coil so we can better integrate your results with know coil design theory?

Coil wire type, solid, stranded, strand size and number of strands
Wire gauge (overall)
Wire insulation type and thickness
Coil diameter ID and OD
Number of coil turns on TX and RX coils
Self Resonance of each coil
Length and type of coax cable connecting coil to machine
MOSFET part number used to drive the TX coil
Size of the smallest gold target detected
Value of damping resistor
TX pulse frequency and pulse length
DC voltage driving the coil

Getting a delay of 2.5uS is a very low number and many variables need to all be pointing in the same direction to achieve this. Your answers may help forum members better understand how many of these variables interact.

Thanks

Joseph J. Rogowski

[Ferric Toes]

I managed a 2.5us sampling time on a Surfmaster PI coil using this method, it's simply DYNAMITE on small gold.

Hi Sean, Is it useable on the wet sand and in shallow salt water?

Eric.

[Sean_Goddard]

Then use thicker wire. The lower the series resistance, the higher your Q will be, of course then you run back into the interwinding capacitance problem. Always a trade off isn't there ;-)

If you space out the coil using a flat basket weave and wind 100Lbs FLOUROCARBON fishing line as an inter winding spacer then you will made a VERY fast High Q coil. If you are using a dual coil, wind the RX coil PARALLEL to the TX coil i.e. side by side in a FLAT format and you will have the lowest capacitance, fastest coil possible. I managed a 2.5us sampling time on a Surfmaster PI coil using this method, it's simply DYNAMITE on small gold.

[Altair]

I use Litz wire for my coils. The size of wire is 175/46 and 400/46. My question is does a basket weave coil perform better than a standard wound circular coil. I am trying to raise the "Q" values to deliver better coil performance. Best to all Jim

I think it depends to your application. If the low inter winding capacity is one of the most important parameters for your circuit, may be basket coil is better, but also circular coil could be constructed with some trick to reduce capacity; for example: use material with a small relative constant dielectric as inter wires separation.

[James]

I use Litz wire for my coils. The size of wire is 175/46 and 400/46. My question is does a basket weave coil perform better than a standard wound circular coil. I am trying to raise the "Q" values to deliver better coil performance. Best to all Jim