Dual Field on SURF PI

[golfnut]

All I want to make a dual field coil for the Surf Pi - (silverdog long board)

Anyone done a good one already.


Looking for 30cm air test on UK £1 coin

Steve

[golfnut]

bump

[Comp]

Hiya!!!! Somebody has done this, I KNOW I read it on here, somewhere,.. but blessed if I can find the thread, now!!!!!!!

They broke the connection from R7, with the junction of R6 (the damping resistor, )and coil, and placed the second winding in the 'gap' (from end of R7, to joint of R6/main coil),
if I remember correctly,... seemed to work OK, but cant recall any more details,... anyone else remember the thread?????


Cheers, Fred

[6666]

The simple KISS explanation of dual field coil is basicly this


say you have a 10 inch 300uH coil
you need to split it into two windings
the 1st being 150uH 10 inch winding
the second being 150uH 5 inch winding
wired in series, same direction


you will probably get other reply's

[bernte_one]

field increasing effect is better if the inner coil has near 2/3 of diameter than outer coil
(coil coupling effect)
outer coil 30cm
inner coil 20cm till 23cm or in that area

looking for user aziz and his analyzing of different type of coil

regards

[maikl]

Dual Field Pi Coils http://www.geotech1.com/forums/showt...ght=Dual+Field

[golfnut]

Sure thx guys, hadnt realised it was 2 Tx coils in series.

Steve

[Vortxrex]

Hiya!!!! Somebody has done this, I KNOW I read it on here, somewhere,.. but blessed if I can find the thread, now!!!!!!!

They broke the connection from R7, with the junction of R6 (the damping resistor, )and coil, and placed the second winding in the 'gap' (from end of R7, to joint of R6/main coil),
if I remember correctly,... seemed to work OK, but cant recall any more details,... anyone else remember the thread?????


Cheers, Fred

Hi Fred, I think this was the post you were referring too: http://www.geotech1.com/forums/showt...wer#post127934

Its not a Dual field, it was for separate RX & TX coils