RBJ-4 Receiver

RBJ-4 US Navy Receiver

Click to view Circuit in a new window.

General Description

The RBJ series of receivers were built by the National Radio Company, of HRO fame, for the U.S. Navy.

The RBJ was designed for use at shore stations or aboard naval vessels. The sets were supplied in mounting racks suitable for table mounting.

The RBJ is a nine valve superheterodyne using 9 plug in coil sets to cover the range from 50 - 400 kc and from 480 to 30,000 kc. See below for the range of each box. The receiver is powered by a separate power unit.

Technical Data

There are 2 stages of RF amplification, mixer, HF oscillator, 2 stages of IF amplification at 456kc, a bias type triode detector and a resistance coupled audio output stage. A triode is used for amplified and delayed automatic volume control. A BFO is provided for CW reception.

Audio output is either through headphones - 10mw at 600 ohms - or via a loudspeaker output circuit providing 2 watts at 5000 ohms.

Restorers please note that an audio output transformer will need to be provided to match 5000 ohms to loudspeaker impedance.

The antenna feed can be configured for either single wire or balanced feed.

Power Requirements: The RBJ, RBJ-3 and RBJ-4 were supplied with a 230 vac power supply CNA-20125, while the RBJ-1 and RBJ-2 were supplied with 117 vac supply type CNA-20090. Both supplies were rated at 50/60 cps single phase.

The HT voltage required is 240v at 70 ma whilst the LT is 6.3v at 3.4A.

The valve complement is:
V101 6D6 1st RF AmplifierV104 6C6 HF OscillatorV107 6F8 2nd Detector/AVC
V102 6D6 2nd RF AmplifierV105 6D6 1st IF amplifierV108 6C6 CW Oscillator
V103 6C6 First DetectorV106 6D6 2nd IF amplifierV109 6V6 Audio Amplifier

The all up weight of the unit complete with mounting rack, power supply and coil drawer is 145 lbs. (appx 66kg)

Illustrations of the set

View of the interior top and bottom. interior top view interior bottom view

Coil boxes and coil box detail. coil boxes coil box

Coil storage box label and coil box front coil box label coil box front

Back to Top or Go to Home page.

© Ian O'Toole, 2009. Page created: 22/11/04 Last updated: 4/12/2009