I can GUARANTEE you that that box is using a switch mode power supply
(SMPS).
IF it is external, it is ALMOST a trivial exercise to determine the
proper voltage and amperage requirements and supply it with clean DC
current....
It WILL be a lot quieter with the SMPS gone.... now, the ROUTER inside
the unit will also be making a racket as well.... that requires some
additional RFI "trickery" to defeat.... but it IS doable.
______________________
Clay Autery, KY5G
(318) 518-1389
On 11-Oct-19 08:11, James Gordon Beattie Jr wrote:
Jim,
Try running the cable box from a battery and isolated from the power grid. There
may be a switched mode power supply on that device or another one on another customer
that is creating and conducting the noise. Also, do this with no other cables
connected to the cable box and first add the hdmi, then the cable feed.
73,
Gordon Beattie, W2TTT
201.314.6964
_______________________________________________
RFI mailing list
RFI@contesting.com
http://lists.contesting.com/mailman/listinfo/rfi
|