[RFI] Linksys Router Birdies

Rick Karlquist richard at karlquist.com
Thu Mar 11 17:29:47 PST 2010

Christopher E. Brown wrote:
>> What is the best method of getting rid of router birdies? I have a Cisco
>> Linksys router with both wireless and wired connections. There's a long
>> run (50ft) of unshielded CAT 5 cable going to the shack which I'll be
>> replacing with shielded cable. I'm told the wallwart can be a source of
>> RFI as well.
> 2.4 inch Type 31 toroids, on the power and on each ethernet cable leaving
> the device.  For a long run put one on each end of the ethernet cable.
> Consult Jims paper for the proper # of turns for max supression on the
> freqs the birdies are bothering you.

I had trouble with my LAN cable wiping out the AM broadcast band.
It probably would have screwed up ham bands too, except it was too
far away from the ham antennas.  I just applied ferrite toroids to the
LAN and power connections and that fixed it.  Be sure to use big
toroids with multiple turns.  Don't try to use beads with one "turn"
going through them.

Rick N6RK

More information about the RFI mailing list