ON AND OFF THE AIR:
* How do you know a presidential election year is in the works? One clue is that Vice President Dan Quayle is a scheduled guest tonight on ABC's "20/20" (at 10, Channel 13).
Host Barbara Walters is the interviewer of not only Quayle but his wife, Marilyn. And while Walters can be counted on to ask some tough questions of President Bush's presumed ticketmate, such a national forum seems one more step in the rebuilding of the Quayle image.
Just last month for example, he was well received in a speech to the Baltimore Council on Foreign Relations. And just this week he launched a preliminary campaign salvo at the Democrat-controlled Congress and its bank scandal.
Now if Quayle could only get "The Tonight Show" heir-designate Jay Leno to lay off with all those jokes.
* Musical variety, once a frequent feature on television, is hard to find these days. The revived "The Smothers Brothers Show" on CBS and ABC's disastrous "Dolly" of a few years back were the most recent broadcast network efforts.
But cable's Nashville Network is one place to look, for the service that bills itself as "The Heart of Country" is launching a new series this weekend.
"The Statler Bros. Show" premieres at 9 p.m. tomorrow, with guest star Barbara Mandrell appearing with the Statler quartet of Harold and Don Reid, Phil Balsey and Jimmy Fortune. Regulars on the show include Rex Allen Jr., Janie Fricke, Royce Elliot and Butch Baker.
* In contrast to what we learned in school, many scholars now suggest that Christopher Columbus was hardly the first European visitor to North and South America. But did a Nordic king named Woden-lithi really cross the Atlantic and sail up the St. Lawrence River way back in 700 B.C.?
That's among the questions to be asked tomorrow night in the open-minded radio show "Hieronimus & Co.," airing at midnight on WCBM-AM 680.
Monday marks our observance of Columbus Day, and in recognition the radio show introduces some other possible visitors to our shores before Columbus, including Druids said to have visited Vermont in Julius Caesar's time, Phoenicians who once lived in Iowa and many others.
* And in a related radio exploration, National Public Radio is launching "Vanishing Homelands," a three-part series on the continuing consequences of New World cultural collisions such as Columbus' arrival on western shores undeniably caused.
In tonight's "All Things Considered" (at 5 and 7 p.m., WJHU-FM 88.1), a report focuses on Christian missionaries in the Bolivian jungle; a report in tomorrow's "Weekend Edition" (8 a.m.) looks at a Colombian Indian tribe now trying to reclaim ancestral homelands, and a final report in Monday's "Morning Edition" (6 a.m.) examines the Dominican Republic's discomfort with the coming celebration of Columbus' voyages.