CW paddle distortion: Cable Modem RF susceptibility?

K9SO

For years, I've been fighting CW transmit distortions when operating paddle CW remotely. For example, I've never been able to get my Maestros to work on paddle CW and I've resorted to using RemoteRig's capabilities which functions much better.

Recently, I've noticed my SmartSDR "network quality" bar graph dropping from green into yellow and then into the red when I'm transmitting. It drops to red when the RTT gets bad and measuring the RTT end to end I've seen times higher than a second. That's when the RemoteRig solution runs out of headroom too.

Using Wireshark and some creative pinging, we've isolated the suspect link in the overall Internet path to be from the input side of my transmitter site router through the cable modem there and out to the first Spectrum gateway. No other path in the overall link changes at all. The path is very stable except when I transmit. Obviously, the suspect part is the cable modem itself not behaving well in the presence of HF signals... and yes, I'm talking PowerGenius levels here. I've hung more CM chokes around the thing than Carter had little pills but nothing seems to help.

All my grounds are good (single point) and I'm running out of ideas to try.

Anyone else had to battle this problem?

73,

Fred, K9SO