[Ham-Mac] RFI getting into computer

[Jack Brindle]

Guys, you are looking in the wrong place. The USB is working  
properly, communicating with the hub. This is proven by the fact that  
the phantom actions are being properly formatted into the USB  
protocol. The computer is receiving it properly, with the data  
passing all the proper checks and all. If there were a problem on the  
bus itself you would be seeing a large number of connects/disconnects  
on the bus.

I would suggest the problem may be due to inadequate bypass filtering  
on the actuator input to the mouse's microcontroller. Actually, the  
bypassing may be proper, but inadequate for the amount of RF being  
thrown at the mouse. The solution is probably more in the area of  
reducing or eliminating the RFI rather than opening up the mouse and  
adding bypass capacitors.

The USB specification calls for rather well shielded cable using a  
twisted pair for the USB signaling. It is pretty difficult to RFI  
this connection.

On Jun 17, 2006, at 3:38 AM, Thomas M.Beaudry wrote:

>> Ferrite cores on all monitor, power and audio cables to
>> reduce RF getting into electrical. Would not put them on
>> USB/Firewire as that seems to cause problem with their
>> ability to transfer data.
>
> I think the problem is that the cables are poorly or non-shielded.   
> Ferrite cores should make no difference with a well-shielded cable.
>

- Jack Brindle, W6FB
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