What is a characteristic of a random-wire HF antenna connected directly to the transmitter?

A random-wire antenna is exactly what it sounds like: a single wire of arbitrary length connected directly to the transmitter or an antenna tuner. Unlike a balanced dipole, a random wire is an unbalanced antenna that relies on the station's ground system as the other half of the radiating circuit. Because the transmitter chassis and station ground are forced to act as the antenna's counterpoise, they become an active part of the radiating system. This means station equipment may carry significant RF current during transmission. This RF current can cause common 'RF in the shack' issues, such as distorted audio, erratic computer behavior, or even mild RF burns to the operator when touching the equipment chassis.