Type CZC-46129 receiver of the Model RBO radio-receiving equipment
Type CZC-46129 receiver of the Model RBO radio-receiving equipment

Use.-Ship entertainment-MCW and voice.

Frequency range.-540 to 1600 kc. and 5550 to 15600 kc. in three bands: (540-1600) (5550-9550) (9200-15600).

Power required for operation.-110/1/58-62, 85 watts.

Description.-The Navy Models RBO and RBO-1 are designed for use as entertainment receivers aboard ships of all types. They are specifically designed to provide optimum performance and high-quality reception of voice or tone modulated signals, on all frequency bands for headtelephone or loudspeaker reception. The two models are the same except for minor component differences in the AVC circuit, and the addition of a noise limiter in the RBO-1 equipment

The equipment is provided with a self-contained rectifier type power unit which supplies all required operating voltages upon connection to a suitable a-c source.

Band switching and tuning are accomplished by conventional methods. Tuning is facilitated by an electron ray indicator on the front panel. The receiver is tuned to resonance with the frequency of the received signals when the "shadow" halves of the indicator approximately meet.

The audio output signal level is adjusted by the volume control, which varies the signal level that is applied to the grid of the first AF amplifier. Automatic volume control provided in the second detector limits the gain of RF amplifier, detector, and first IF circuits in proportion to the strength of the incoming signal. The fidelity control adjusts a rheostat which operates, in conjunction with a series connected fixed capacitor, in the plate circuit of the first AF amplifier tube to limit the high-frequency response of the receiver.

Inverse feedback is incorporated, within the audio output circuits, to maintain a relatively constant voltage across the primary of the output transformer, with varied output loads. Four output circuits provide for the use of a 600-ohm head-telephone set with one of three speaker facilities: one to ten 600-ohm speaker amplifiers, one 600-ohm permanent-magnet type loud speaker, or one 5,000-ohm permanent-magnet type loudspeaker. Facilities are also provided, in the form of separate auxiliary terminals at the rear of the receiver chassis and a suitable switching arrangement, for connecting a phonograph pick-up to the input circuits of the audio-frequency amplifier.

This equipment is especially designed to minimize radiation from the high-frequency oscillator. This is accomplished by isolating the antenna input circuits from the first detector and high-frequency oscillator circuits, through the use of extensive shielding and filtering, and by the employment of a type of construction which reduces, to practical limits, undesirable circuit coupling by virtue of circulating currents in common shields.


Tube complement

                            | Number   | New type
Function                    | of tubes |  No.
RF amplifier                |   1      | 6K7
HF oscillator               |   1      | 6J5
First detector and mixer    |   1      | 6SA7
First & second IF amplifier |   1      | 6SK7
Second Detector, AVC        |   1      | 6H6
First AF amplifier          |   1      | 6J6
Second AF amplifier         |   1      | 6SJ7
AF power output             |   1      | 6K6GT
Tuner indicator             |   1      | 6E5
Rectifier (full wave)       |   1      | 6X5GT
Total                       |  12
Type of receiver.-Superheterodyne.

Type of reception.-MCW and voice.


Input impedance.-Single line antenna.

Output impedance.-600 and 5,000 ohms.

Power output.-2 watts to speaker, 30 milliwatts to phones.

Antenna.-50 to 200 feet maximum single wire.

Weights, dimensions, and Navy type numbers:

  Unit              | Navy type | Height | Width  | Depth  | Weight
                    |           | Inches | Inches | Inches | Pounds
RBO, RBO-1:         | CZC-46139 | 12.75  | 20.5   | 18.5   |   130
Receiver unit       |           |        |        |        | * 165
Equipment (ocean    |           |        |        |        |
  packed).          |           |        |        |        |
* Gross.
Acessories.-Not furnished by contract: Antenna, phones, and speakers.


The information enclosed here is excerpted from:
Catalogue of Naval Electronic Equipment-April 1946- NavShips 900,116.


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