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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