> -----Original Message-----
> From: Ron Rossi
>
> How might incorrectly wired RJ connectors effect this
> condition. If the correct pairing is not maintained I would
> expect that there would be a higher level of radiation.
In my shack, all the ethernet cables are commercially manufactured. My
tests indicate that the 14.029 garbage originates from the circuitry in my
8-port switch and/or DSL modem (and in each PC's ethernet card) and gets
onto the cables as "common mode" energy. Each ethernet cable thus becomes
an antenna. That's why putting ferrites at both ends of a cable knocks the
RFI level down so much.
For common mode junk on a cable, I don't think the quality of the pairing or
twist will have a large effect, since "common mode" signals are -- almost by
definition -- on *all* the wires in the bundle.
Also, altho the stuff is actually generated in the switch and modem, etc.,
the dimensions of those boxes are very small compared to 20 meters, and
they're not real good antennas on their own. In support of that, I found
little improvement from shielding these plastic-housing units. In fact,
simply by treating the cables with ferrites, and not worrying at all about
direct radiation from the electronics units themselves, the signal on 14.029
became virtually inaudible. This is on a CC A-3 tribander mounted 50 feet
directly above my shack and the offending cables and associated circuits.
Bud, W2RU
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