[RFI] Fixing Pin 1 Problems

Jim Brown jim at audiosystemsgroup.com
Thu Jan 13 13:31:35 PST 2011


On 1/13/2011 1:15 PM, Roger (K8RI) wrote:
> So, I
> physically grounded the shield in the mike cable to the "grounded"
> chassis.  No more hum.

Yes, that fixed the problem. But that had NOTHING TO DO WITH GROUND (the 
EARTH).  It was simply that the cable SHIELD needed to be connected to 
the SHIELDING ENCLOSURE to make it function as a shield.  Now, a 
connection to earth is important for other reasons, including lightning 
protection and preventing hum and buzz from power line leakage currents 
when equipment is interconnected, but it has no effect on SHIELDING.

73, Jim Brown K9YC


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