On Sun,1/11/2015 8:35 PM, Wes Attaway (N5WA) wrote:
Network cable that isn't properly constructed with the required twisting of
wire pairs could introduce major RF problems.
Or RJ45 connectors that are improperly installed. CAT3, 5, 6, and so on
are PAIRED cables, and the pairs must be terminated in pairs (that is,
to the right terminals). For example, Brown and Brown/Wh is a pair,
Orange and Or/Wh is a pair, and so on. Twisted pair cable inherently
resists coupling and crosstalk of noise and RFI, and is at least as
important than a cable shield in that regard (and MORE important at HF
and below). Each one of those twisted pairs is a signal circuit -- but
for that noise rejection to work, they must be wires as pairs.
Cross-wiring Bn/Wh to where Or/Wh should be would defeat the benefits of
twisting!
I know all stations have different situations, but I have run high and low
power off and on for many years with numerous routers and computers and
CAT-5 cables located within a foot or two of transmitters and have never had
a problem with anything.
Proximity of wiring or victim electronics to transmitters is not what
matters -- it's the proximity to ANTENNAS, because they are what radiate
the RF.
I think there is something going on other than CAT5/router issues. What
about the house wiring, your coax connector soldering, station grounding?
A connection to the EARTH is rarely part of a solution to hum, buzz, or
RFI. Rather, BONDING is important, and so are Pin One Problems. Proper
grounding and bonding for ham stations is addressed in this tutorial.
http://k9yc.com/GroundingAndAudio.pdf
Do you notice any other RFI ill-effects other than the CAT5/router issues?
Some DSL systems are notoriously susceptible to RFI. AT&T Uverse is one
of them. Bud, W2RU, author of the "Practical Antenna Handbook," went
through some serious work to cure the RF to his DSL from his 160 and 80M
operation. I recall exchanging email with him, and also seeing
reflector posts from him.
73, Jim K9YC
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