Dave Marsh ranks "Wavelength" #253, between Jimi Hendrix's "Purple Haze" (#252) and "I'm So Young" by The Students (#254)
Van Morrison's fascination with radio, both as a vehicle for the transmission of music and as a metaphor for the transmission of spiritual power, amounts to an obsession. It's familiar from the stunning "Radio! Turn it up" chant which concludes "Caravan", the best song on the great 1970 album Moondance. But it reached a state of perfected grace in this single, though (relatively speaking) it flopped on the very medium it celebrated.
Like John Lennon just across the Irish Channel, Morrison first heard rock and roll and R&B through a fog of pops and crackles on foriegn stations like Radio Luxemborg. No nation in Europe had any reason to regularly program such music as part of its cultural fare, but Luxemborg rented time to any record label that cared to buy it, a kind of institutionalized payola that had kids all over the continent and throughout the British Isles glued to their receivers during the few evening hours each week when new releases were highlighted. Luxemborg's station was far away and fifties radio receivers poor; the miasmic distortion that resulted must have struck Morrison, like Lennon, as a built-in part of those strange, foreign records, a built-in part of their mystique even if it wasn't there when you played the records themselves. These secret sounds traveled only the transnational airwaves.
So when Van sings "I hear the Voice of America calling on my wavelength" he's not referring to the US propaganda channel(which was mainly aimed at the "captive nations of Eastern Europe" and hardly would have played any such trash as Rock and R&B anyhow) but to the music itself and the static that accompanied it. Against swirling synthesizer riffs that evoke that late night radio distortion, he sings about the transforming power of broadly transmitted music. The moments when pop music becomes the thing of glory of which even such a bitter, whimsical, cynical mystic can sing:
In "Wavelength", Van declares that the message of those American voices on his radio was "Come back, baby, come back". And so he moved to the States. And in 1967 or 1968, found himself living in Cambridge, Massachusetts. Hardly anybody knew who Morrison was; his last hit had been that one about the "lover in the grass" referred to in these lyrics and the music he was working on, which became the immortal Astral Weeks, was not inclined to incite frenzied attention.
Van stayed up late and listened to the radio. In the night, he heard a strange voice calling to him once again, in the form of a frog-voiced preacher who spun blues and R&B records and shouted jive talk into the after-midnight air on station WBCN, which devoted the rest of its programming to hippie album rock. One night, Van worked up his nerve and called the station. It was a small place; the deejay answered his own phone.
Van was stunned to discover that the disc jockey was a white man named Peter Wolf. Wolf was stunned to be called by a guy who was one of his musical heroes, the writer not only of "Brown Eyed Girl" but of "Gloria", a song his own band, the Hallucinations, regularly performed. So the guy from Belfast became friends with the kid from Bronx and they stayed in touch for the next couple of decades.
And that is a little bit of what Van Morrison means when he sings "You never let me down, no, no."