On 5/19/2012 4:24 PM, Jim WA9YSD wrote:
To be with in NFPA, NEC you can make a common mode choke by slipping some beads
around the electrical ground connecting to the station ground as long as you do
not wind the electrical grounding conductor into a coil to make a choke. This
will separate the station ground and electrical ground so as not to create a
ground loop.. Exception to the rule.
NO, NO, NO, NO! First, beads do virtually NOTHING below 100 MHz or so.
Second, adding a choke that DID do anything would violate NEC because
NEC requires a LOW IMPEDANCE bond. Lightning is NOT a DC event, it is
an impulse with a fast rise time, which makes it an RF event. Thus, to
satisfy NEC, the bonding of grounds must be a low impedance to at least
5 MHz.
As to a "tuned" or shielded ground -- pure BS.
Sorry for the late reply -- I'm en route home from Dayton.
73, Jim K9YC
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