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The Rise of Radio Engineering 1920-29
Other Manufacturers
In the 1920's radio manufacturing was a hot item to invest your money in. Radio companies sprang up all over the US from coast to coast. Many of them had to keep the cost down to compete. One way to cut cost was to patent your own design and be sure of yourself that it doesn't conflict with RCA patents or "bootleg" by copying and hoping that RCA won't find out.
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TRF Receiver with attached Utah horn speaker using 5- UV-201 or UX-201 tubes. $60 (1925). Owned by Charles Freshman, his approach was to sell low price radios that look as good as his competitors, but with low parts counts and simplest circuits to make large profits. Result high failure rates and he closed down when the depression hit.
Across the Atlantic from Europe
Three tube Tuned Radio Frequency Reflex set and features the use of early solid state diodes made by Westinghouse called Copper Oxide Rectifiers, configured as voltage doubler. Uses Ediswan (Mazda) AC/P, AC/SG and AC/HL tubes. 230V AC input. Receives Long Wave and Short Wave (actually Medium Wave)
Pye Radio and later Pye Communications was a leading electronics manufacturer in the UK, and continued into the 1990s when it became part of Philips. Pye was key to UK's efforts to build the proximity fuse that help defeat Germany in WW2.
Electronic Restoration and Upgrades
Finished Electronic Restoration
<<< Power supply sectionThe original transformer was removed so I managed to get a toroidal power transformer (left side) to run at 115 / 230 VAC. which I will bring out for North America/Europe power systems. Thanks to a service manual, I got the correct high voltage secondary. Notice the two copper oxide rectifiers on the lower right. Made by Westinghouse. Configured as voltage doubler.
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SHOWCASE: The Return of the RCA Radiola 17 Model AR-927 (1927)
I had a Radiola 17 for 20 years, it was one of my early restorations. The cabinet had some damage and I was still learning about refinishing. In addition that one was not in great shape mechanically, but it had the original lamp hood (more about that in Ideas for Restoration). I sold it for about $35 which wasn't much but I was glad to part witih it. About 2 years later, I happen to walk into an antique mall in Orange, CA and the dealer wanted to part with one because he needed to clear out inventory. This one came with all the tubes and the cabinet was in good shape so I picked it up for $60. The inside was original and in working condition. I didn't have to replace or repair anything including the tubes. All that was needed was a new line cord, antenna and ground wires plus alot of cleaning (almost 90 years of dust). That sad part was the lamp hood was missing, which is very common and I've seen people pay over $50 for one (close to the cost of the radio) on places like Ebay.
The nice thing was that I was able to keep the cabinet intact, refinish the wood to original appearance and best of all made a lamp hood out of a measuring spoon. The radio works and looks like it just came out of the RCA assembly line in 1927. The Radiola 17 was RCA's first AC operated or socket powered radio. It is a TRF design and uses 6 Triodes (4-226s. 1-171A and 1-227) plus a 280 rectifier. It was prone to oscillate due to the triode interelectrode capacitances. It was replaced after a year with the Radiola 18. Price of the Radiola 17 was $130 and 179,917 were made.
Go to IDEAS FOR RESTORATION section to find out more about the Radiola 17 including the lamp hood.
RESTORED with LID OPEN RF and AF SECTION POWER SUPPLY
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