[jcims]

(Note: As coderjames points out this could be dangerous tinkering. There is typically steady-state noise at 125MHz from Ethernet so it's not that we're putting more energy into the spectrum with this, but adding signal in the form of morse code could draw a lot of attention/distraction to pilots and ATC in the area.)

FWIW very brief example of 125MHz tone loss when going to 10MHz demonstrated here when my slow internet gets done uploading:

(Unpleasant sound warning)

https://youtu.be/JmyA5QEtAxA

[Dahoon]

If your Ethernet emissions can be picked up by pilots or air traffic control, your are doing something wrong on purpose.

[jcims]

Sure but I could see this being used as a side-channel attack to exfil data from a customer in a red team assessment. Practitioners love little tools like this.

Also I'm not talking about 30 miles away...but if a completely intact cable can be detected with a directional antenna from 100m, an intentionally buggered patch cable installed at a client site for this purpose could pose a bigger concern for pilots in the area. (edit: I might be more tuned in to this (har har) because I live in the flight path of a medical helicopter that flies over at ~500' almost daily.)

Ham folks can seem a bit hair-triggered chicken littles with RF hygiene but it's the product of decades of fighting noise from people that aren't aware of the externalities of their actions.