[RFI] RF slowing down upstream cable modem data

[Matt NQ6N]

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