[MarkSummer]

> How would you isolate something like this?

On Navy ships you have a slew of EM radiating emitters, not only from your own ship, but also from other ships that may be close by. For that reason, a lot of time and effort is spent EM-hardening equipment and cables from being susceptible to EMI and also ensuring radiating emitters don't exceed spectrum and intensity limits - whether they're intended to radiate (e.g. antennas, radars, range finders, etc.) or not (e.g. generators, motor controllers, etc.).

Mil-std-461 (downloadable here (1)) tells you how to test equipment/environments to ensure EM radiated emissions and equipment susceptibility are within standard/tolerable limits. If problems arise on a ship, there is shipboard testing that can be used to pinpoint the culprit and then you can mitigate (e.g. ferrite beads, shielding, proper grounding per Mil-std-1310, removing cable loops, etc.).

Sounds like these folks could use some good old fashioned EMI testing.

1. https://quicksearch.dla.mil/qaSearch.aspx