The "American Radio Relay League" that was mentioned in the episode is a national association for amateur radio. It is still in existence today.
The call sign used in this episode, "QTQRT2," is not now, nor has it ever been, a legal call sign. All amateur radio call signs in the United States begin with the letter A, K, N or W.
Ham operators use Q signals and were originally used to reduce the number of characters sent by Morse code. The fictious call contains QRT which means "Stop sending" or "Shall I stop sending?"
The car approaching the checkpoint in the opening credits is a 1954 Lincoln Capri convertible. The Highway Patrol cars at the checkpoint are 1955 Buicks, as is Matthews' patrol car. The car Herb Williams is driving is a 1955 Plymouth. Mel's car is a 1955 ford convertible.