I recently installed a D-Link DI-704 cable modem gateway for my two
computers. This provides a 4-port 100/10baseT switch with hardware
"firewall" for the cable modem input. I installed it a few hours before the
start of the CQ WW DX contest on Friday evening - a major mistake!
At the start of the contest, I began noting a lot of spikes at various
frequencies in the 10m band. I quickly determined that the DI-704 was the
culprit. I wound a mix-43 torroid around the power adapter cord, and this
reduced the RFI problem a fair amount. However, it was still noticeable all
over 10m. The signal was getting out over the two lengths of cat 5e cable
connected to each computer. I tried a mix-43 torroid on one of the cables,
but this was ineffective.
I'm trying to pursue the issue with D-Link technical support, but haven't
yet received a real reply from an engineer. None of my other computer
hardware or peripherals emits anything approaching the RFI that this cable
modem gateway produces.
I wonder if others have had success in home-networking RFI issues? Will
shielded cat5 cables help at all? Are there any other methods available to
reduce the RFI emitted by these cables?
It's clear that the problem is the DI-704 gateway unit. But, the unit does
exactly what I had bought it for (providing an inexpensive hardware firewall
with internect connection sharing via the 4-port switch). Thanks for any
Richard Eckman KO4MR
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