If the problem is bad enough, I might try electrically isolating the two systems using only optical or fiber optic cables to connect between the computer infrastructure and the transmitter infrastructure, with perhaps two ground straps to a single point ground stake being the only conductive item or wiring between the two subsystems. TOSLink converters can be used with legacy radios that have to connect to computers via "sound cards". Amazon and others seem to sell opto-isolated USB to serial links for CAT control. I use a networked SDR radio (Hermes Lite 2), so I might try using 2 fiber optic network media converters and multi-mode fiber to connect the computer to the radio with complete electrical isolation. You also need to make sure the computer case, cables, keyboard and mouse are decently shielded. And look for common mode currents or high SWR on your feed line resonating at 80 MHz due to the feed line lengths, antenna imbalance, lack of counterpose or radials, etc.