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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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Freshmen Masterpiece 5F5 (1925).
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.
Freed-Eisemann NR-6 (1924) $150.
Freed-Eisemann used Hazeltine Neutrodyne circuit to remove unwanted oscillations when bringing the gain up to hear weaker stations in TRF receivers. They had to go to court that this design does not conflict with RCA patents and they won.

BEFORE RESTORATION

Inside the NR6

Changing Tubes by Opening top Lid
The Patented Hazeltine Neutrodyne Circuit Concentric Coils form a Neutralizing Capacitor
NR6 Station Listing and Operating Instructions
Inside the 5F5 showing the tubes and speaker horn made by Utah Speaker.
Echophone Model C (1929) TRF Receiver, Made by Ufonic Rsdio Co LTD, Hollywood CA.Previously they were in Santa Clara CA. Licenced by RCA through Gillfilan Brothers Los Angeles. Early AC operated Cathedral Radio with 6 Tubes- 3- 01A, 27, 71A and 80. After the company was sold to a new owner around 1930 and moved manufacturing to Waukegan IL. A few years later Hallicrafters bought the company and that was the end of the Echophone line.
Complete restoration done. Purchased August 22, 2021 and completed October 20, 2021.
On-Off switch on the back. Fairly common for early AC operated sets.
The brightest tube glow are from the 01A's, The leftmost tubes are the 71A and 80 and the short tube in the middle is the 27 tube.
Unlike most sets, Ufonic has no chassis. The radio is built on the backcover.. Tubes, tuning and RF section is built on phenolic board.

Across the Atlantic from Europe

Pye 350/C (1929) "All Electric Three" Early AC Electric TRF Reflex Radio. Pye Radio LTD, Cambridge, England UK.
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.
Restoration done Jan 2020
Condition As Purchased NOV 2020

Electronic Restoration and Upgrades

Resistor voltage divider (upper right corner)Has several open windings. Rather than try to repair it and risk more damage, I decided to add a 2 watt resistor of similar resistance in parallel.

Finished Electronic Restoration

ABOVE: Checkout using a external Sonora high impedance speaker. BELOW: Closeup of Volume, Reaction and Band select controls.
BELOW: Rear view. On lower right, I added a line select switch for 115 or 230 VAC. The new power transformer provided the inputs for this. The vacuum tubse: AC/P audio amp (lower left), AC/HL detector/amplifier (next to AC/P) and the AC/SG RF amp in the upper center (mounted horizontally}.




<<< 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.




<<< RF and Audio SectionUsing only 3 tubes and has separate tuning sectionns (Similar to a TRF Reflex design like the Crosley Trirdyne). American AC sets around fhis time usually have extra RF amplification using 2 extra tubes and used ganging tuning.
ABOVE: The cabinet was in very good condition. Only cleaning and a beeswax rub was needed.
ABOVE: Typical setup of the Pye 350/C. I am using a Sonora external speaker and above it is a 115 VAC to 230 VAC step up to adapt radio for US operation. I installed a new UK cord to the radio.

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SHOWCASE: The Return of the RCA Radiola 17 Model AR-927 (1927)

ABOVE:

BEFORE RESTORATION

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