[RFI] Ethernet RFI Elimination?

[Eric Rosenberg]

I have a 3-computer/single printer wired network (using a Linksys
router/print server) in my house.  For a variety of reasons, I can't run
a wireless network. 

Jim Brown, K9YC, posted an interesting item this past month that touched
on RFI generated by Ethernet (CAT5) cabling.  In the post, Jim mentioned
some specific birdie frequencies.  I dialed them up on the Orion and, lo
and behold, there they were. 

My questions are: 

What other frequencies will I hear the Ethernet (I believe Jim's posting
stops at 10 MHz)?  

What can I do to lower/eliminate the RFI?  The router is about 20 feet
away from the radio, the shack computer, cable modem and local printer
are within 3 feet of the radio. 

Thanks in advance, 

Eric W3DQ
Washington, DC