[RFI] RF slowing down upstream cable modem data

[Grant Saviers]

A long list of ideas:

On my amp 240AC I used a commercial line filter plus a multi turn green 
wire going thru a 240-31 core to keep rf out of the AC power grounds.  
(I assume the amp has it's separate ground wire to the single point)  
Technically not UL, but it has worked and the safety issue is beyond 
remote.  You could add another filter for the router AC, and a green 
wire ferrite if it has a green wire connection.  An AC line in the US 
isn't balanced and clamp on chokes can only do common mode.  Maybe you 
need more chokes on the 40m feedline.  Check the grounding block on the 
RG6 entry.  All RG6 connectors need to be really tight.  It's unlikely 
there is leakage into the RG6 except at connectors.  Maybe give each one 
a hard tug test.  Replace any store bought "RG6" jumpers with custom 
made ones, cable installers have made them for me.

Grant KZ1W

On 11/8/2018 11:53 AM, Matt NQ6N wrote:
> On 40m when I transmit at full power my upstream cable modem data
> connection experiences packet loss and slows down.
>
> I've added substantial amounts of ferrite to the CATV coax, ethernet cable
> and power cable.
>
> Just wondering if anyone has ideas for other approaches to reducing this
> RFI that might work.  I tried adding additional fair rite type 31 snap-on
> beads along the length of coax between the house and the cable company's
> hardline but they seemed to have no effect.  I also tried wrapping the
> cable modem in aluminum foil and connecting the foil to the station's
> single point ground, which also seemed to have no effect.
>
> My transmissions on 40m seem to have no impact on the performance of
> download performance, only upload performance. The cable modem is a high
> end DOCSIS 3.1 model from Motorola.
>
> I had a new run of coax installed by the cable company today from the house
> to the hard line and it did not reduce the problem.
>
> Suggestions for other things to try would be much appreciated.
>
> 73,
> Matt NQ6N
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