This is probably as good an early summer morning as any, TV Column fans, to remind you that it's time to switch to your warm weather breakfast nook straps again . . .

Last year's favorites -- madras and white linen -- are definitely out, according to strap designers (although sensible TV Column fans probably can -- and will -- stretch another summer out of them) . . .

But if you're in the mood for a breakfast nook redo, we hear that denim is back this year. For himself, Captain Airwaves plans to stick to the reliable old loose-weave knit he's favored for so many summers (unlike some of the TV Columns in August, it breathes) . . .

And next week we'll try to get you a couple of exciting items that will require a breakfast nook strap-in, you know, for kind of an early-summer strap test! . . .

So saying, let's report that the June 17 broadcast of NBC's "1986," which will debut as a magazine the week before, will be devoted entirely to the subject of terrorism . . .

"Nightly News" anchor Tom Brokaw will travel to Europe for interviews and will be anchor (instead of regular coanchors Roger Mudd and Connie Chung) for the program . . . which airs the day before the trial of three hijackers of the liner Achille Lauro is due to begin in Genoa . . .

Included in the program: previously unseen tapes from that controversial May 5 interview (on "NBC Nightly News") with Abul Abbas, the terrorist chief who has been accused of plotting the Achille Lauro takeover, during which an elderly American was murdered . . .

Dick Clark's "America Picks the Number One Song" Wednesday night won against a couple of reruns between 9 and 11 p.m., but the ratings couldn't have had anyone humming in the ABC sales departments . . .

"Song" registered a ho-humming 16.5 national Nielsen rating and a 28 percent audience share, beating the two-hour pilot of "Blacke's Magic" on NBC, with a 13.1/22, and a repeat of "The Big Chill" theatrical movie on CBS, which did an 11.0/20 . . .

In case you missed it, a spokesman for the ABC special said 1.5 million telephone calls (at 50 cents a pop) were placed during the broadcast . . . as callers voted Elvis Presley's "Hound Dog" the number one song in the 1955-65 decade, and Simon & Garfunkel's "Bridge Over Troubled Waters" tops for 1965-75 . . .

Voters in the East and Central time zones picked Tina Turner's "What's Love Got to Do With It?" as the 1975-85 favorite, while callers in the West chose Lionel Ritchie's "All Night Long" Also in the News

Mark Walton, who has had a number of top assignments at the Cable News Network bureau here since CNN began in 1980, has been named corrrespondent, Special Reports Unit, at CNN Hq. in Atlanta . . .

CBS News correspondent Bob Simon will be released from a New York hospital today. He has been having serious back troubles since taking a fall on a recent assignment to Kuala Lumpur, Malaysia. No surgery ordered yet on a ruptured disc, but he'll be an outpatient for a week in Manhattan before he returns, moving slowly, to work . . .

As expected, NBC won the May ratings sweeps in the Nielsen book, which ran from May I through Wednesday, with a 15.6 rating and a 27 percent audience share . . .

ABC (and its "North and South: Book II") finished second with a 13.3/23, while CBS trailed at 13.1/23 . . .

NBC was up 8 percent over last May's Nielsen sweep ratings, ABC was up 4 and CBS was down 6 . . . Moving Right Along

Nine area cable systems, serving some 300,000 subscribers, have committed a channel to C-SPAN II to provide live, uninterrupted coverage of the U.S. Senate floor proceedings starting Monday (early on the menu during the Senate TV experiment: the debate on income tax reform proposals) . . .

Area systems include the Capitol Connection in Washington; Prime Cable in Bowie; Tribune United in Montgomery County; and Jones Intercable in Alexandria . . .

Also taking C-SPAN II: Hauser Cable in Arlington; Media General in Fairfax; Columbia International in Lake Ridge; Jones Intercable in Anne Arundel County; and Metrovision in Prince George's County . . . Local Ratingzzzz

Channel 7 showed growing strength in the Arbitron ratings book for the local May sweeps, which ended Tuesday on ARB . . . but once again the discrepancies between ARB results and the Nielsen ratings figures -- an ongoing battle in this market -- are evident . . .

To save wear and tear on TV Column fans' peepers this morning, we're saving the Nielsen numbers until Monday, despite tearful pleas from Channel 9 . . .

(Channel 9, which shows slippage in the Arbitron figures below, is throwing a party today to celebrate its across-the-board Nielsen triumphs. Captain Airwaves, who thinks the eye care of loyal TV Column fans comes first, is not on the guest list) . . .

We have included a comparison of ARB figures for each time period from a year ago in May . . .

In the morning network race, "Good Morning America" on Channel 7 leads with a 5 rating and a 24 percent audience share (0, 0 change); "Today" on Four has a 4/16 (+1, +2); and "CBS Morning News" on Nine did 3/15 (0, -2) . . .

At noon, Mondays-Fridays, Nine news leads with a 6/28 (0, -2); followed by Seven news at 5/26 (+1, +5); Four's "Here's Lucy" at 2/11 (down -3, -13 from noon news a year ago); and Panorama on Five 2/10 (-1, -2) . . .

Afternoon network shows (12:30 to 4) M-F: Seven leads with 8/34 (0, 0); followed by Nine 5/19 (-1, -6); and Four 3/3 (0, 0) . . .

From 4-5 p.m. M-F: Seven leads with 7/22 (0, -1); followed by Four 4/14 (-2, -3); and Nine 4/13 (-1, -2) . . .

From 5 to 6 p.m. M-F: Seven news is first with 6/16 (+1, +3); followed by Nine news 5/15 (-3, -5); and Four news 5/14 (-2, -3) . . .

From 6 to 7 p.m. M-F: Nine news is first with 7/17 (-2, -4); followed by Seven news (to 6:30) 7/16 (+1, +1); and Four news 6/15 (-1, -1) . . .

Network news M-F: "CBS Evening News" leads on Nine with 9/20 (0, -1); followed by "ABC World News Tonight" on Seven at 6:30 8/18 (+2, +4 from a year ago at 7 p.m.); and "NBC Nightly News" on Four 6/13 (-1, -2) . . .

From 7:30 to 8 M-F: "M*A*S*H" on Five leads with 10/22 (-1, 0); followed by "Wheel of Fortune" on Nine 10/21 (-2, -4); "Entertainment Tonight" on Seven 7/16 (-2, -2); and "New Newlywed Game" on Four 6/13 (+1, +4 over "$100,000 Name That Tune" a year ago) . . .

Between 4 p.m. and 8 p.m., Channel 5 programming averages 8/20 (-1, -2) while Channel 20's lineup did a 2/6 (-3, -6)) . . .

Primetime Monday-Sundays: NBC is first on Four with 13/24 (+1, +1); followed by ABC on Seven 12/33 (+1, +2); CBS on Nine 10/19 (-3, -5); Five 6/11 (-1, -2) and Twenty 3/5 (-1, -2) . . .

Late News M-F: Seven is first in ARB with 9/23 (-1, -1); with a tie between Nine and Four at 9/21 (-2, -5) (-1, -3) . . .

The 10 o'clock news on Five has a 7/13 (0, +1) . . .