Deforest Radio Telephone & Telegraph Company first sold this receiver in 1922. A single tube receiver that required a headset for listening or could be connected to one of the early amplifiers of its day. The operator would change coils for different frequencies. It originally sold for $36.00.
The instructions for battery hook up, ground and antenna are in the lid.
The recommended antenna and ground set-up in 1922.
Although officially called an "Open Set", for obvious reasons it is more commonly referred to as a "Breadboard" radio. The 3955 is a TRF radio without regeneration. The inventor of the regenerative circuit, Edwin Armstrong held a patent on his invention beginning in 1914 and A. Atwater Kent, the founder of Atwater Kent Manufacturing, did not want to buy a license and pay a royalty on the radios he sold. (Click photo on left for schematic.)
Atwater Kent sold the model 3 with a tuner, detector and two stage amplifier, leaving a space between the detector and tuner for the buyer to add a variometer for regeneration.
The Atwater Kent 3955 was designed to use one UV-200 tube and two 01A tubes or three 01A tubes. .
Production started in December of 1922 at General Electric for RCA. The Radiola II is a TRF radio with regeneration. GE stopped producing the radio in 1924.
As you can see below, the Radiola II used two UV-199 tubes.
Early models use two "B" batteries mounted in the back for 45 volts of power. Later models could drive a loudspeaker by using 90 volts and a "C" battery to reduce distortion.
The Model 5 was the only open set officially sold under a single digit model number, the other open sets were given model numbers by collectors. The radio consisted of a Type 11 tuner and a five tube amplifier unit that used one tube for detection, two for RF amplification and two tubes for audio amplification. The tube line up was five UV- 01A tubes or one UV-200 as a detector and four UV-01A tubes. (Click photo on left for schematic.)
With sales beginning on September 7th, 1923 the model 5 was Atwater Kent's attempt to reduce the complexity and cost of radios. However, the model 5 had poor selectivity with only one tuning device and the number of radio stations was growing rapidly in 1923. Radios designed for tuning in one or two stations, which is all many people could receive before 1923, were doomed to obsolescence.
Despite being a poor receiver and corresponding poor sales, the model 5 is one of the rarest and most sought after radios among collectors today.
In 1922 RCA came out with the RC model, which was the 1921 RA tuner and DA detector/amplifier consolidated into one unit. A TRF receiver with regeneration, it originally sold for $133.
The RC could tune from 170 to 800 meters of the broadcast band and more with the optional "Long Wave Load Coil".
The RC could use a UV-200 and two UV-201 tubes or three UV-201 tubes.
The model 6 was designed to use four UV-01A tubes or one UV-200 as a detector and three 01A tubes in the T/A unit.
At the left end of the radio is a Type 11 Tuner, next is the Detector. The smaller unit in the back is a RF transformer and in front of that is a Potentiometer.
The RA-10 was capable of tuning both broadcast and long wave frequencies.
The RA-10 needed a detector tube unit to produce an audio signal.
The DA-2 , also sold in 1922, was designed to be paired up with the RA-10 providing a detector and two stages of amplification.
The second RF stage boosted the signal so weaker stations could be listened to with a speaker horn.
The model 7 , with a single circuit tuner, suffered from poor selectivity.
The Crosley 51 was the next step up from the Crosley 50, adding an amplification stage so a speaker horn could be used for listening.
Two UV- 01A tubes comprised the original line up, later models could use UX based tubes and an added connection for "C" allowed the user to use a more powerful amplifier tube, such as a 71A or 112A .
The Museum's Crosley 51 is a great performer for a simple design, bringing in many stations clearly with plenty of volume.
The RS is a TRF radio with a single AM circuit and regeneration.
Designed for using two brass based, tipped WD-11 tubes. Those tubes were larger than the later model WD-11 tubes in the photo which made them easier to remove.
The RS was manufactured by Westinghouse for RCA.
The 9A is a TRF radio without regeneration.
The 9A was designed to use four UV base 01A tubes or a UV base 00 detector tube and three 01A tubes.
The XL-5 is a TRF radio without regeneration, three AM circuits and sold for $115.00
The XL-5 was designed to use five 01A triode vacuum tubes.
The XL-5 required 5 volts filament power, 22 volts detector power and 90 volts for amplification.
The model 20 uses a five tube line up consisting of five 01A tubes or a 00A tube as a detector and four 01A tubes.
In the hands of a skilled operator, the model 20 is an excellent receiver with good sensitivity and selectivity along with a relatively strong amplifier for it's era.
The 3R3 Special is a TRF radio with regeneration.
The 3R3 Special was built with an antenna loading coil, seen below attached to the left side interior of the radio cabinet.
The 3R3 was designed for to use three UV- 01A tubes.
The 9C uses two variable condensers instead of a Type 11 tuner and a Coupled Circuit Tuner used in the earlier versions.
The 9C could use four 01A tubes or a type 00 tube as a detector and three 01A tubes.
TRF radio with regeneration, two AM circuits.
The CR-8 is a one tube receiver designed to use a UV-200 vacuum tube.
The CR-8 has a range of between 150 - 1000 meters.
The Atwater Kent model 4700 (10C) was the fourth and last version in the Model 10 series of radios. The designation "10C" was used to identify the radio in documents from the factory so, like the Model 5 it could be considered correct to refer to this model as a 10C . (The first version, the Radiodyne, can be found in the notables section. It has its own interesting story.)
Design changes made to the 10C included elimination of the potentiometer that controlled RF amplifier grid bias and replace it with 800 ohm damper resistors. Another change was eliminating the by-pass condensers on the RF amplifier filaments.
Two versions of the 10C were produced, a shorter more compact version also designated the 10C was manufactured on a twenty-six inch board, three inches shorter than the standard model 10C.
The type 281 was a top of the line receiver in it's day with an $80.00 price tag. A TRF design with regeneration, it had a range of 175 to 600 meters.
The type 281 was designed to use a UV-200 tube.
The 281 could be used with headphones or paired with the matching 521 two stage amplifier above to drive a speaker horn.
It wasn't too hard for Atwater Kent to bring out the model 12, it's basically a model 10 with an extra audio amplifier stage. Back in the 20s you bought this one for bragging rights.
The 4910 model 12 exchanged the detector/two stage amplifier for a detector/single stage unit followed by a two stage amplifier unit.
The follow up to the 4910 model 12, the model 12B had an additional potentiometer on the left hand side next to the first variable condenser.
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