On 11/6/2012 4:38 PM, Missouri Guy wrote:
From what I've read, there's some question of whether or not to
run the grounding wire, along with the "hot" and neutral
wires, through a say, a 2.4"i.d. #77 mix toroid. There are no other
grounding conductors at the test bench.
Even the best power line filters provide NO attenuation of common mode
noise on the AC line, because the green wire bypasses the filter.
(While power filters SAY that they attenuate common mode, they define
common mode differently than we do (they define it as noise between
neutral and green, while the proper definition is a signal that is
common to all conductors on a cable). AND -- most RF noise on the AC
line is common mode noise, and lots of baseband noise is power-related
leakage current on the green wire.
Thus, the ONLY good defense for RF noise on the AC line is a serious
ferrite choke formed by winding all three conductors around a #31
toroid, using as a guide the measured data for single conductors in
appendix one of http://audiosystemsgroup.com/RFI-Ham.pdf
For baseband (power-related) noise, the best defense is bonding from
chassis to chassis of all equipment, AND fixing any missing or improper
bonds of the green wires inside equipment. The proper connection of the
green wire is directly to the chassis or shielding enclosure, never to
the circuit board first. Another common mfg error is a chassis
connection that fails because there is paint between the chassis and the
connection lug (VERY common in Astron power supplies).
73, Jim K9YC
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