[RFI] Internet Modem / Router Cable Length and RFI

[Tony]

All:

I'm about to relocate the wireless router in my home which currently 
sits next to my internet modem connected with a short run of CAT5. 
Relocating the router will lengthen the CAT cable by 40 feet so I'm a 
bit concerned about RFI birdies, noise etc.

That said, I was wondering if it's better to relocate both cable modem 
and the router to the same location to keep the CAT cable short. I would 
then have to lengthen the coax cable for the modem instead of the CAT 
cable.

The question is: which setup has more potential for RFI?

Thanks

73, Tony