If American popular music is the Mississippi River, then Nick Spitzer takes his “American Routes” show wading in the upland streams and creeks that feed the Big Muddy. Just as the country is no melting pot, its popular music is no puree – instead, it’s a big old pot of stew, with chunks of all kinds of savory stuff in there to chew on.

With 25 years of listening to rock, folk and jazz under my belt, I find I’ve become a hobbyist musicologist. I love to listen to rhythm and blues tunes from the late 1940s and early ’50s that, though they would never make it into my collection, fascinate me in that I can hear a direct musical lineage through the ’60s and ’70s to the “roots” music of today.

“American Routes” is based in New Orleans – appropriately enough – and syndicated by Public Radio International. Maine Public Radio added the show, which airs from 1 to 3 p.m. Saturday, last month as part of extensive programming changes that included the elimination of live Metropolitan Opera on Saturday afternoons and drew the ire of a longtime, loyal following.

Tuning in several Saturdays, I found “American Routes” – the new program in the Metropolitan Opera’s time slot – a pleasant mix of the new and old, and refreshingly eclectic.

Even though I feel like I’ve learned something with each listen, “American Routes” is not a dry, academic program. The shows I’ve heard have a theme – prison life in song, was one – which the host uses as a peg on which to hang everything from 1930s folk songs celebrating outlaws to electric blues from the last decade.

Spitzer keeps the show fast-paced – short sets of songs, followed by quick breaks in which he might throw in a historical aside along with the names of the artists and songs, mixed with the occasional short interview. As pleased as I am that he avoids being pedantic, my only criticism is that the show tends to come off as a little too slick and polished. I wouldn’t mind hearing a bit more historical or musical context, a bit more chatting about the theme.

Spitzer also succeeds in avoiding sounding like he’s dug out his grandfather’s scratchy old 78s and Library of Congress field recordings. It’s often difficult to tell – sonically and culturally – whether a song is from the ’50s or ’90s, and I suppose this is the point of the show.

I especially enjoy the personal “Aha!” moments, when I can connect the dots between the music of my generation and that which came before. During the prison-theme show, Spitzer played a folk song called “Cole the Younger” from 1939. I have a recording of contemporary folk singer Mary McCaslin singing the same song, which I assumed she had written. The arrangements are identical.

“American Routes” interprets “roots” music pretty broadly – the show Saturday featured music by Taj Mahal, Merle Travis, Louis Armstrong, Miles Davis and Sonny Rollins, The Kinks, Otis Redding, James Brown, Lee Dorsey, Professor Longhair and a newer group called Southern Culture on the Skids. If nothing else, it will restore one’s faith in and appreciation of the richness of our musical heritage, despite the dominance of the homogenized sounds of Madonna, ‘N Sync and Nashville country on commercial radio.

“Talk of the Nation,” 2-3 p.m. weekdays

The best thing about National Public Radio’s “Talk of the Nation” is host Juan Williams’ interruptions. His “Hang on, hang on, hang on!” or “Now wait a minute!” are signals that the blather of some public mouthpiece is about to be laid bare.

It’s not that Williams is rude, or that he embarrasses or attacks the speaker. Instead, he has an extraordinary ability to get at the kernel of truth – if there is one – in what that speaker believes. He cleanly slices through the layers of obfuscation to expose the underlying premise. The interruption often is followed by revelation, which Williams repeats for emphasis or clarity.

“Oh, so you’re saying you believe there WON’T be gridlock in the next Congress,” he’ll say, and the guest senator often pauses a split second, as if he or she is surprised at the admission, but must agree with the conclusion because Williams has deftly – and refreshingly – taken the speaker at his word.

And Williams doesn’t resort to the Bryant Gumbel technique of stating what he thinks the speaker really believes, the “Is it not true that you hope Senator Ashcroft will be humiliated during the confirmation hearings?” approach that any media-savvy person can deflect without revealing anything.

“Talk of the Nation” first aired on MPR during the aftermath of the presidential election. As a political junkie, I needed some – any- information, analysis or just plain rank opinion during the spells between news, and “Talk of the Nation” gave me my fix.

MPR’s director of radio services, Charles Beck, correctly notes that along with the news programs and interview shows, public radio ought to offer some analysis, and some opportunity for callers to sound off about events of the day. Without something like “Talk of the Nation,” I am reduced to turning to someone like Rush Limbaugh as I drive from here to there to get some take on the latest political development.

And there needs to be an alternative to conservative ranters like Limbaugh. I don’t necessarily object to his viewpoint, but Limbaugh can never surprise anyone. If Bill Clinton had put together a medical team that cured cancer, Rush would tell his listeners that the physicians were all Republicans and that Bubba timed the cure to help Hillary get elected president. The bottom line for Rush and his ilk is the same: conservatives, good; liberals and progressives, bad.

I suppose you could make the case that Williams is part of the liberal media that dominate public broadcasting. But he is a moderator, keeping his opinions to himself and instead focusing on the daunting task of getting spin doctors and politicians to say something clearly, and with some sincerity. By this measure, Williams succeeds.

“Talk of the Nation” also avoids as guests the usual suspects who fill the Sunday morning inside-the-Beltway TV shows.

I don’t know whether it’s by design or whether he can’t book the professional party hacks because they’re busy, but there are some fresh voices here.

The callers, too, are fairly articulate and bright, a nice change from the “ditto heads” that dominate conservative talk radio.

“Talk of the Nation” restores some intelligence to radio political discourse, proving that “talk” doesn’t have to be synonymous with “rant.”

“Whad’Ya Know?” 11 a.m.-1 p.m. Saturdays

As I drive on my Saturday errands – to the recycling center, the pet food store, the redemption center, the gas station – “Whad’Ya Know?” is the perfect radio companion.

I’ve had to describe “Whad’Ya Know?” from time to time, and the best I can come up with is that it’s an offbeat quiz show where no one really wins anything, accompanied by some great live jazz and hosted by a wisecracking Jewish Midwesterner.

Michael Feldman starts the show with a comic monologue of sorts, then chats up the studio audience. The show is live, usually from the Midwest, which accounts for its charm. Midwesterners – if I can indulge in some stereotyping – are just so darn polite and wholesome, but not without their quirks.

Feldman is a funny guy, and reminds me in a way of Groucho Marx as he was on his TV quiz show, “You Bet Your Life.”

The fact Feldman is unleashing that slightly caustic, almost always witty Jewish humor deep in the Midwest makes it all the funnier. He’s sort of the anti-Garrison Keillor, if you can imagine such a thing.

MPR has aired the first hour of the show for several years, but beginning last month, now carries the show in its entirety.

“Whad’Ya Know?” is somewhat unpredictable. There is often a call-in guest who is usually a writer, and sometimes even a guest musician. The piano and bass jazz duo that play live during the show are half the draw for me – solid, straight-ahead bop.

But I, like the millions who like to test their knowledge of the trivial against the people who make it to Regis Philbin’s TV show, do get a genuine kick out of the obscure questions and answers. Feldman chooses someone from the audience to play with a caller who is selected by correctly answering a qualifying question.

The often odd couple try to sort out the correct answer, which generates a few laughs, as do Feldman’s not-too-subtle hints.

It ain’t exactly like eavesdropping on a Mensa meeting, but on Saturday morning, who wants that?