New technologies often make people nostalgic for the cutting-edge gizmos of a bygone era. That is especially true for radio buffs like our father, Ron Keno. He has vivid memories of the entire family gathered around the radio in the 1930s and '40s as history played over the airwaves-President Roosevelt's "fireside chats," the Hindenburg disaster, the attack on Pearl Harbor. On the lighter side, he recalls the music of Bing Crosby, and Orson Welles's sinister voice as "the Shadow." Modern in Dad's day, the plastic tabletop radios from the 930s, '40s, and '50s are highly collectible today. They are prized for their sleek Machine Age styling, luminescent dials, and colorful cases. And as long as they have the potential to function, there's no shortage of techies who will tinker with the tubes and transformers to get these old radios back "on the air."

BAKELITE TO BEETLE
The first plastic radios from the early 1930s were boxy little numbers made of black or brown Bakelite, a molded resin. By the end of the decade, new developments in plastics allowed for more creative styling and a broader range of colors. Manufacturers such as Fada, Emerson, and Crosley took their cues from Art Deco icons like New York City's Chrysler Building and introduced streamlined designs in pistachio Plaskon, blue-streaked Beetle, and candy-colored marbleized Catalin. By the end of World War II these early plastics were being supplanted by cheaper polystyrene, and Art Deco was giving way to more aerodynamic Jet Age style. Because Catalin radios were fragile and relatively few survive, prices start around $500 and go up to more than $25,000. But most plastic radios range from $25 to $1,000, depending on rarity and condition. For beginning collectors, online auction sites, flea markets, and yard sales are good places to look for inexpensive models. For about $50 you can find a vintage radio with simple circuitry in good condition to decorate a room or to fiddle around with, according to Mark Stein, author of The Complete Price Guide to Antique Radios (Radiomania Publishing).

WHAT TO LOOK FOR
When you find a model that catches your eye, carefully evaluate its condition. Plastic radios were vulnerable to the heat generated by the tubes, so examine the case for chips, cracks, and warping. Repairs on plastic are difficult to do well and may reduce the value. By holding a radio up to the light you can detect whether a crack has been repaired with auto-body filler, which appears opaque. Also, many early Bakelite radios had paint "baked" on at the factory, which tends to chip as it ages. The original surface, even if it's chipped, is usually worth 10 to 50 percent more than one that's been stripped and repainted.

Missing or mismatched exterior grilles, knobs, or dial lenses also diminish the value, but you can often find replacements at swap meets or in Antique Radio Classified (www. antiqueradio.com), the magazine (and online resource) for radio collectors. Many old radios are missing their back panel, which was typically made of cardboard. But since the back is rarely seen, its absence doesn't affect value much. The exceptions are models with a plastic back, which was integral to the design. Its absence can slash values by as much as 25 percent, says Stein. To get an old radio working, you might have to replace the capacitors, the tiny cigar-shaped components that store an electrical charge. You may also have to change the occasional vacuum tube, which amplifies a radio's signal. Though replacement parts are available online from various dealers, Stein recommends leaving such repairs to a professional. To locate a repair shop, search online under vintage or antique radio restoration. For audiophiles who want modern technology but like the look of old radios, reproductions are available through several specialty electronics and home furnishing retailers. Our dad has long since sold off most of his radio collection, but lately he's been on the prowl for one iconic model to bring back that excitement from his youth. He's got his eye on a 1936 Remler with a shiny black Bakelite case and a contrasting ivory Plaskon grille. It has a great, graphic design. But for him, as for so many collectors, the appeal really goes deeper. As Dad likes to say, there's nothing like the soft glow of an old radio dial lit up at night.