RARE soviet military aviation tube receiver 1930s

Description

Actual pictures.
US (universal superheterodyne) - the name of several connected radio receivers, produced in the USSR from the second half of the 1930s. They were used mainly in aviation. A large number of decommissioned receivers of this type were used on collective and individual amateur radio stations.
All US receivers are tube superheterodynes with one frequency conversion, adapted for receiving radiotelephone (with amplitude modulation) and radiotelegraph signals.
The US receiver, or US-1, was developed in the mid-1930s. The receiver is all-wave, on eight octal lamps with a metal ballon, for its time quite compact and light, with a very tight layout. According to some sources, it was based on the experience gained by Soviet specialists in the US at RCA, where they studied American technologies and participated in the development of radio equipment.
The frequency range is from 175 to 12000 kHz, that is, covers the long, middle and low frequency portion of short waves.
The sensitivity in the telegraph mode is 1 ... 4 μV, in the telephone - 4 ... 15 μV.
The intermediate frequency is 115 kHz. Because of such a low IF at the receiver, low selectivity on the mirror channel (see Superheterodyne), which is reflected in the manuals.
Dimensions without protruding parts - 320 × 130 × 170 mm.
Weight - 5,1 kg.
Power - from the airborne network of the aircraft through the umformer or from another external source.
The receiver was produced from 1937 to 1959, first in Moscow, and from autumn 1941 - in Gorky, in several modifications, the last of them - the US-P 1948. Used in the radio stations of the RSB of all modifications, RAF, RSR-1 and others. The same receiver for civilian use was made under the name of PR-4 (PR-4-B, PR-4-P) with a calibration scale in kHz, and not in fixed numbers of fixed waves, as in US. PR-4 was part of the radio station RK-0.05A.