Frank Sinatra may be The Voice. But for 50 years, radio maven Sid Mark has been the guy behind the guy -- a gentleman's gentleman who brought his tonic, sober mellifluousness to the AM dial via Fridays with Frank, Sundays with Sinatra and the nationally syndicated Sounds of Sinatra on Saturdays (all currently at home on WPHT 1210 AM). That smooth but authoritarian tone comes not only from an immense collection of Sinatrology (the largest outside of Frank's own vaults) but also from the knowledge gleaned from a relationship that lasted 40 years, until Sinatra's passing -- one archived through countless exclusive tapes of conversations recorded between old friends.

City Paper: Does "good music" skew to young audiences? It would certainly seem to, what with how much the Kralls and Connicks sell.

Sid Mark: I can only comment on the Sinatra thing, but at WPHT, it's that show that has the youngest numbers. The parents pass the music along. If you hear Sinatra the whole time you're growing up, you go through phases -- times you don't want to hear it, then you tolerate it, then you enjoy it. Either way, you pass it on.

CP: That station has so many right-wing talk shows. Is that your cup of tea?

SM: Funny you say that. I was on Michael Smerconish's morning show today. He's conservative. Right down the middle. The absolute middle. Hannity. Rush Limbaugh. That's their act, you know, the right wing. And they do it well. I don't listen. Besides, look at the last Arbitrons. Sinatra is right there with them -- even beating them at some hours.

CP: By the time you met Sinatra in '65, your show had already been a hit. Was it tough to get to meet him?

SM: It was 10 years in. We had really grown in prominence. But nothing from him. I wrote to him, to Capitol. All in long hand, so they probably disregarded the letters. [Laughs.] I even talked with Ella Fitzgerald, the Ellington guys -- all of whom played the Red Hill where I was working. I was only a kid. I'd bug everyone. Impossible, they'd say. Then Frank recorded an album at The Sands with the Basie band. And we really wailed it, played it for five consecutive days. It sold in Philly more than anywhere in the country. California called and wanted to acknowledge me. What do you want? "Nothing, just to meet Mr. Sinatra." They offered to have me meet Sammy Davis or Buddy Greco. I knew those guys. Thanks. But no. We hung up. Next day, they call back. "He wants you to be his guest in Vegas. At the Sands." "I can't afford it," I said. But. When you're Frank's guest -- everything is taken care of.

CP: He obviously took more than a little shine to you, knowing that in the Beatles era, you'd be a valuable ally. What did he say?

SM: He had a pretty good dossier on me: what I played, when I played. What I was and who I was. But with that, his middle name wasn't "Albert." It was "Loyalty." I asked him for nothing. Not even an autograph. I was just pleased to be around him. And I must've been well behaved. At our table was daughter Nancy, Leo Durocher, Jack Benny and his wife. Milton and Ruthie Berle. It was pretty heady.

CP: When was the last time you saw him?

SM: Right after the Duets projects came out. We were sitting having dinner at a Chinese restaurant at The Sands and I asked him if he had seen the Daily News. The banner above the headline had announced that Sinatra knocked out Pearl Jam for the No. 1 slot. He was thrilled. He followed every band that came down the pike. Not too long before our dinner, he had a night at his house with Bono, Dylan and Springsteen. Howyalike that? When I handed him that headline, I knew it meant the world to him.

CP: How old are you?

SM: That's the title of a great Sinatra tune -- "I'm old enough to know the difference between infatuation and romance." I'm 72.

CP: How much longer do you want to do this?

SM: Like Frank said -- until I get it right.

Sid Mark can be heard on WPHT 1210 AM, Fridays 7-10 p.m., Saturdays 7-10 p.m. and Sundays 8 a.m.-1 p.m.