When it comes to vintage radios, collector Lewis Newhard follows this clear signal:

Between World War I and World War II, he says, "The best radios in the country were probably made in the Philadelphia-Camden area."

"Philco had unbelievable engineering - the complexity of the radios they made, the skills that were required.

"Atwater Kent, he was a different type of character. His radios are highly collectible because he had unique ways of making them.

"And RCA was known for exotic, beautiful cabinets."

Radio has proved to be quite the survivor, a wonderfully portable medium that still provides information and entertainment wherever we happen to be. And those who appreciate its earliest incarnations are enthusiastic fans. Newhard is a member of the Delaware Valley Historic Radio Club, sponsor of the Kutztown Antique Radio Meet May 11 and 12, which will bring together collectors from all over the country to show, sell and discuss old radios and their parts.

Jeffrey Ray, senior curator of collections at the Atwater Kent Museum - where "Wonderful World of Radio" is on exhibit through Sept. 16 - says Kent's company originally made electric motors.

"In 1922, his factory got an order for 10,000 Bakelite radio headsets, and he knew something was up," Ray says. "At the time, you bought parts for radios and assembled them yourself - it was very much a guy thing."

Because of the patents RCA held, for a while the Camden company was the only one that could sell radios that were fully assembled. But this quickly changed as other firms entered the business. Atwater Kent was making complete radios by 1923 and in 1924 moved to a new plant on Wissahickon Avenue, part of which still exists.

"What [Kent] was offering to do better was improve the clarity of reception and quality of sound," Ray says. "Kent and his distributors signed contracts with various cabinetmakers to make cabinets to fit his radios, some of which came from central Pennsylvania."

Atwater Kent led the world in radio production in 1928, manufacturing more than a million sets, but there were many other players in the radio game.

In Popular Art Deco: Depression Era Style and Design, authors Robert Heide and John Gilman note in a chapter on the "Radio Age" that families would often buy expensive console radios on $5 payment plans. When the Depression hit, prices dropped, and more table models became available.

"While Atwater Kent, Stromberg-Carlson, and Sparton sets were in the more expensive category," the authors write, "the most common were from RCA, Philco, Zenith, and Silvertone's all-wave 'Wonder Radio,' which sold through the Sears catalogs."

Today, radio collecting is driven by two major motivations. Newhard, who worked for Western Electric, and fellow Delaware Valley club members focus on the science of the instrument. "There are plenty of demonstrations of the high-end vacuum-tube technology - a lot of working pieces."

The club's Kutztown event has become one of the largest of its type, drawing enthusiasts from as far afield as New Zealand. "You will see a cross-section of Americana from the 1920s through the 20th century," Newhard says.

"A lot of pieces are restored, and some stuff is parts. You ought to see it - they're trading at 1 o'clock in the morning. It's all lit up, and it's very friendly."

Though some value the technology, high prices for old radio models are principally driven by attractive outer cases. An important milestone in radio collecting was the 1990 publication of John Sideli's Classic Plastic Radios of the 1930s and 1940s, still available used. Sideli was fascinated by the color and form of the art deco and moderne designs, and helped fuel the collecting of certain choice models.

Sotheby's referred often to his book in its May 2004 "Pop Around" catalog for its sale of Pierre Lescure's collection in Paris. The sale, which included pinup art, toys and jukeboxes, opened with a large selection of pre-World War II radios.

The most colorful were made of catalin, a phenolic plastic manufactured in New York that could be tinted scarlet or butterscotch or grass green. A late-1930s Automatic Radio Co. "Tom Thumb" model in red brought $10,940.

An Air King 52 skyscraper-design radio from 1933 in astonishing lavender plastic and a Fada L56 "All-American" from 1939 in marbled orange catalin sold for $13,128 each. A 1938 Emerson BT245 "Cathedral Tombstone" model in scarce marbled blue brought $8,022.

Other desirable radios were cased in colored mirror glass, including the Sparton 1186 console model designed by Walter Dorwin Teague. A blue mirror and chrome set sold in Paris for more than $58,000, and that December at Sotheby's in New York another brought $114,000.

Collectors can find more information on old radios and their design in current books from Atglen-based Schiffer Publishing (www.schifferbooks.com). These range from volumes focusing on particular makers such as Philco and Zenith to Genuine Plastic Radios of the Mid-Century, which covers hundreds of stylish models from various manufacturers, now valued at $25 to $100, that might turn up in attics and garage sales.

Families may no longer cluster around a cabinet radio in the living room, but the medium has endured. People now listen to satellite radio while they travel on airplanes and online stations as they sit at computers.

And when the electricity goes out and nothing else works, we grab the battery-powered radio to find out what's going on.

Antiques | If You Go

"Wonderful World of Radio" runs through Sept. 16 at the Atwater Kent Museum of Philadelphia, 15 S. Seventh St. Hours: Wednesday-Sunday 1-5 p.m. Admission: $5; seniors and children 13-17, $3; 12 and under, free. Information: 215-685-4830 or www.atwaterkentmuseum.

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From 2 to 3:30 p.m. tomorrow, the museum will present "Radio Broadcasting in Philadelphia." On hand will be local radio personalities Jerry Blavat, Tony Brown, Tom Moran, and Karin Phillips for a panel discussion moderated by Dean Tyler.

The Kutztown Antique Radio Meet opens at noon May 11 and runs continuously until about 5 p.m. May 12 at Renninger Antiques & Farmers Market, 740 Noble St., Kutztown. Admission: free; parking and overnight camping also are free. Information: www.renningers.com. EndText

"Antiques" appears monthly in The Inquirer. Read Karla Karla Albertson's recent work at http://go.philly.com/kleinalbertson.