[RFI] RF getting into 4-port wirelss router.

[Jim Brown]

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