RADIO

Think you’ve got a long commute? How about prominent R&B; deejay Tom Joyner, who until last week traveled between radio studios in Dallas and Chicago five days a week. Actually, Joyner--who had been piling up the frequent-flier miles this way for three years--is taking it a bit easier this week: only three days of the 900-mile commute between Dallas’ KKDA-FM and Chicago’s WGCI-FM.