We realized that 1/0 welding cable, carrying thousands of joules from the battery to the cars, was running alongside unshielded CAT5-USB cable. EM coupling between the two not only fouled the signal, but had already burned out a USB port on Gradman's laptop. Gradman solved this by connecting the relay boards to an additional laptop behind the cars. He connected the laptops via Ethernet---which is less susceptible to interference---and frantically rewrote his software lying on his belly on the desert playa.
Gary Numan plays "Cars" with cars