[RFI] UVerse WAP VEN501-AT Interference

Jim Brown jim at audiosystemsgroup.com
Tue Jan 26 21:26:12 EST 2016

On Tue,1/26/2016 6:07 PM, Clark Macaulay wrote:
> They appear to
> be like spurs.  On 20m, the spacing was about 14000 Mhz, 14030, 140060,
> 14090. There is something similar on the higher bands.

It's quite common for RF trash to be radiated from CAT5 cables carrying 
Ethernet signals (and even from wiring inside the box). Radiation from 
Ethernet cables can be effectively suppressed by winding 5 turns of the 
Ethernet cable through a toroid or clamp-on of #31 or #43 Fair-Rite 
ferrite material. Likewise, other cables connected to the router, 
including the power supply cable may need to be choked.

This sort of trash is also typical of switch-mode power supplies, and 
it's quite likely that the one supplied by UVerse is one of that type. 
It's always a good move to replace every switching  power supply you 
find with an old-fashioned linear supply having the same voltage 
rating.  Simply find one of the oldies in your junk box having the same 
voltage rating, cut the cables for both units, check wiring polarity, 
and splice the old supply to the connector that mates with the new unit.

None of this, of course, will kill RF that is radiated by a wiring 
within a box that is poorly built or poorly shielded.

73, Jim K9YC

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