During the flashback sequence, a Pepsi can with a tapered rim is seen on Jeff Fisher's desk. Dialogue sets the scene during the Carter administration (1977-81), but beverage cans with the tapered design weren't introduced until 1987, around the time the movie was filmed.
Early in the film, Barry expresses anger that his producer isn't putting through more interesting callers. He's supposed to be reading examples from the computer screen that displays a list of callers on hold and the subjects they're calling about, but when we see the screen, some of the callers he says he'd like to talk to aren't listed.
The radio station gives its identification as "KGAB in Dallas". Dallas shares its media market with Fort Worth, so all radio and television stations give their identification as being from "Dallas-Fort Worth".
KGAB's radio tower is shown to be in Downtown Dallas. Most radio stations in the Dallas-Fort Worth area are in Cedar Hill, in between Dallas and Fort Worth. While there are exceptions depending on the power of the radio station, if KGAB were as large a station as depicted, its tower would be in Cedar Hill.
When Barry Champlain says that he's going to punish his listeners by playing the Bee Gee's song - Saturday Night Fever, ten times in a row. The record they actually play is Disco Inferno by The Tramps. This may be intentional due to copyright issues however the track is on the OST for Saturday Night Fever.