I hope this doesn't come through as a duplicate. My ISP changed the way
they handle messages and one of my protective programs requires I OK the
exceptions which dumps the mail requiring I do it over.
Be careful with wallwart power supplies.
I have used 8 port LinkSys and Netgear switches on a Gigabit network
(Cat-5 wiring). I'm currently using a LinkSys Router with an 8 port
Gigabit connection plus the 3 frequency wireless capability. The past
switches and the current router sit on top of the Emtron DX-2sp, or the
Yaesu FTDX5000. 3 runs of the unshielded Cat-5 run with the coax cables
to the 100' 45G for abt 75 feet. It's 130' run from the router to the
shop computers. Neither the network or station appear to hear each other
when the bands are dead quiet.
My approach for the last 30 plus years has beet to run cables where ever
is convenient and "IF" there is a problem, THEN address the problem by
fixing the source. There is no expertise involved AFAIK. It's basically
luck. IOW the cabling behind the rigs and computers is a MESS. The only
time I ever had a problem was when I tried to "neaten" up the mess while
running multiple stations on multiple antennas. It took me WEEKS to get
rid of the interaction and cross talk and I was never sure I had all of
the problems fixed.. I have never tried for neat wiring since then.
NOTE : Cat 5 and 6 do this intentionally by twisting signal wires at a
rate to intentionally cancel cross talk (coupling) at the frequencies
used. IOW you can normally bundle network Cat 5 and 6 cables together
with little fear of coupling.
As for earth grounding, I do resort to multiple grounds. There is a
daisy chain grounding the equipment chassis string AND an attempt to tie
each piece of that equipment to earth ground through equal lengths of
grounding cable as short as possible. We are dealing with RF so The
equipment isn't likely to see the short grounds as affecting the longer
ones. The same is true for lightning. Where the 130' of Cat-5 ran
through PVC conduit, induced voltages cost me a bundle with the
Connectors being welded into one UPS, totaling one (state of the art)
new computer and wiping out the NIC in a second computer.
There are two Caveats: Keep antennas well away from network cables and
eliminate, or keep common mode RF on coax to a minimum. IOW, I use
common mode chokes on most of the antennas!
For induced voltages (lightning protection) long runs of Cat 5 need to
be in "grounded" metal conduit. Long runs of Cat-6 needs to have the
shield grounded at both ends.
73, Roger (K8RI)
On 3/29/2018 Thursday 2:22 AM, Jeff Blaine wrote:
In the process of overhauling the shack's wiring, I'm wanting to
replace my existing ethernet switch with a box that is properly
shielded - or at least has one with a low emission footprint. Here i'm
talking about radiation from the box itself - not via the connected
ethernet lan cable runs.
Unfortunately the houses' home-run location terminates a few feet from
my shack and so the switch needs to be located there. I can apply
ferrite / common mode treatment to the power supply and lan cables
that connect to the box. But I also need a box that is properly
shielded from a ham point-of-view. The switches I have now are all of
the plastic-case variety and they all are pretty noisy.
I was hoping someone may have found a "quite" switch that could be
recommended. Some of the semi-pro (e.g. Netgear home-office rack
mount) stuff has metal cases -- but I don't know if that actually
means they are quieter.
73/jeff/ac0c
alpha-charlie-zero-charlie
www.ac0c.com
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Roger (K8RI)
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