On 30/09/10 15:23, Dave D wrote:
Thanks guys... I've never had that problem before. Any tips for what
clamp-on ferrites might work best, or how many? Or the best way to
configure them?

Distributed capacitance is the enemy of any multi turn balun, whether in
solenoid style (eg Ugly Balun) or toroidal winding. You could however
try to exploit the self resonance by placing it in the band you wish to
use, then the issue is whether the resonance peak in Zcm is sufficiently
wide.

The W2DU style ought have sufficiently low self capacitance to operate
below resonance at 800 to 1000MHz. I would look to #61 material
suppression sleeves, but it may be that a lossier material works for
your application.

Owen