[MLB-WIRELESS] OT: RF emissions of Grandstream Budgetone 102 VoIP phones.

[Jason Hecker]

>>As you can imagine, the cat5 is coupling
>>noise from within the device and acting like a honking great antenna.

Any ethernet device is DC isolated from the CAT5 via a transformer that 
does both differential and common mode filtering.  On top of this you 
need to add in extra capacitive decoupling off the centre taps.  Perhaps 
this is defective.  The only short-term fix I can think of is a big 
ferrite clamp or passing the cat 5 through a ferrite toroid a few times 
to present a high impedance on the cat5 above 50MHz.

RS Components (www.rsaustralia.com) in Port Melbourne can sell you such 
a ferrite.  Two turns of the cat 5 through part number 222-4365 as close 
as possible to the eth port should help things a good bit.  Two turns 
through part 260-6492 should do too.

Start a no turns, 1 turn and 2 turns to see how you go.  Too many turns 
will start affecting the ethernet signal.

Jason