Manufactured by Sony Corp., Tokyo.
In the USA, the „Zenith Transoceanic“ portable receivers with the horizontal turret tuner dial were a great success in the late 1960s, Sony adopted the design with the CRF-5080 / CRF-5090, the design was later taken up again in several world band receivers from the Far East.
The set was sold in two variants, the CRF-5090 covers the Air Band in addition to the FM broadcast band and shortwaves. The variant CRF-5080 without air band coverage was sold in Germany (where the possession of sets with coverage of „out-of-band frequencies“ was prohibited), it even got an FTZ approval. In Switzerland, on the other hand, possession of sets covering frequencies pf the PSB was always permitted, only operation without a corresponding licence was illegal. When inspected by the PTT, one had to have the radio tuned to Swiss National radio and faithfully assure that the switch was in the „air band“ position by mistake, or pull a pilot's licence out of one's pocket …
With its horizontal dial and the turret tuner operated from the switch on the right face, the portable radio has a strong resemblance of the late Zenith world band receivers from the „Trans Oceanic“ series.
The portable receiver has a black plastic cabinet, a strong carrying handle on the top and a protective cover that covers the dial and controls and can be slid into the bottom of the set when opened. Like in the Zenith sets, the metal disc world clock calculator is also located here. With its dimensions of 34 x 25 x 16 cm and a weight of 5.7 kg, the „Earth Orbiter“ is one of the still portable portable receivers.
The set can be powered from 110 or 220 V alternating current, with 12 V direct current from a car battery (here Sony uses a unique plug with a common socket for battery and mains voltage) or from eight UM-1 mono cells.
The telescopic antenna is located on the top of the receiver.
The top third of the front panel is taken up by the horizontal frequency dial, the turret tuner is operated with a powerful rotary switch on the right face of the unit, the selected band is displayed in a small window. Small sliding plastic tabs allow you to mark dial pointer positions to find a station again, and the dial pointer has a red LED that lights up when a signal worth receiving is detected. To the right of the frequency dials, there is also a nice analogue S-meter.
Most controls are arranged in a horizontal row just below, from the left the main switch and the headphone jack, the controls for squelch, the BFO for CW / SSB reception and the RF gain control, in its normal position, the RF gain control is automatic (AGC). To the right are the tone & volume control and the switch for the AFC active in the FM broadcast band.
Further below, to the right of the oval speaker, is the main tuning knob with a concentric „Fine Tuning“ control.
Operation of the CRF-5090 is largely self-explanatory. Set the power switch to „ON“, adjust the volume, set the turret tuner with the rotary knob on the right face of the radio until the desired frequency band is displayed and turn the tuning knob until you hear the station …
In the shortwave ranges, select the corresponding band segment. The frequency dial accuracy is poor on the set with only slight bandspread analogue dials. Each range covers several shortwave broadcast or amateur radio bands. To tune in to a station on a known frequency, you have to recognize is from the interval signal or a spoken identification, this is similar to most domestic radios with a somewhat spread shortwave range. On long-wire antennas, the RF gain can be adjusted manually, a switchable BFO lets you demodulate CW / Morse transmissions and, to a limited extent, stronger SSB signals in the amateur radio ranges or sometimes a Volmet weather report.
Technically, the CRF-5090 is a single conversion superhet with an IF of 455 kHz in the AM band and a single conversion with an IF of 10.7 MHz in the FM broadcast band. Unfortunately, I do not have a circuit diagram.
In summary, the Sony CRF-5090 nowadays is a collector's radio, with a classic design comparable to the more modern Zenith receivers. The radio not only receives the international shortwave services (with an insufficient frequency dial accuracy for practical use, however), it also is a good performer in the FM broadcast band, unfortunately the FTZ-compliant version lacks the reception of the VHF aeronautical communication services. In terms of built quality, the Sony set differs considerably from similar-looking cheap Far East radios from Koyo, etc.
Single conversion superhet, analog dials with little bandspread.
The set is equipped with semiconductors.