[LAU] RF noise suppression?

[Rick Green]

I'm using a FOcusrite Saffire pro 26 I/O  with ffado, jack, and Ardour to 
make  multitrack recordings of live concerts, to my emachines M6810 laptop 
running ubuntustudio.  I'm plagued by noise that sounds to me like RF 
interference from the laptop, getting into the audio portions of the 
interface.  It's most obvious when I'm at home trying to mix down my 
recordings, as its almost constant in my monitors and most noticable in 
a quiet room, but it also manifests itself sometimes during shows, showing 
up on the input lines to the interface, which are plugged 'half-way' into 
the FOH mixer's channel inserts, so it invades the PA and the performers' 
monitors.  WHen that happens, I've no other choice but to abandon the 
recording and shut down the laptop.

   Has anyone else encountered this problem?  Got any suggestions how to 
filter it?  I'm going to try some ferrite cores snapped around the 
firewire cable first.  Anything else I might try?

-- 
Rick Green

"Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety."
                                   -Benjamin Franklin

"As for our common defense, we reject as false the choice between our
safety and our ideals."
                                -President Barack Obama 20 Jan 2009