Hi Marcus, Why not try "pyramid" winding as I have with success in making a more compact coil, probably reducing the issues you have now, see....... http://myweb.tiscali.co.uk/wgtaylor/LF%20&%20MF%20
Thanks Gary for pointing this out. This is a good idea, which can help minimizing internal electrical fields and effective capacitance. Actually I have used a very similar technique, the only differe