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The portable radio receiver of the IV class "Selga-403" (UAPP-IV-B) since 1971 has been producing an experimental series (273 radio receivers) by the Riga plant named after A.S. Popov. ,86e6f450b8cc469628ba70bf2947b049The radio receiver is designed to receive radio stations in the DV and MW bands. ,86e6f450b8cc469628ba70bf2947b049Reception is carried out on an internal magnetic antenna, but it is possible to connect an external antenna. ,86e6f450b8cc469628ba70bf2947b049Headphones can be connected to the receiver. ,86e6f450b8cc469628ba70bf2947b049The radio receiver is made according to a superheterodyne circuit with three transistors and an integrated circuit "Ritm-2" / 2KZHA-421 /. ,86e6f450b8cc469628ba70bf2947b049Some copies had a Ritm-1 microcircuit and a board similar to the Selga-402 receiver board, others had their own board, as in the last photo (the photo shows a homemade board, similar to the factory one). ,86e6f450b8cc469628ba70bf2947b049The circuit of the input circuit and the converter is similar to the circuit of the Selga-402 receiver, with the difference that in order to improve the selectivity of reception, an RC filter is included in the circuit of the communication coil of the DV range. ,86e6f450b8cc469628ba70bf2947b049The IF path of the receiver, the detector and the pre-amplification stages are made on one integrated circuit containing 6 transistors, 22 resistors and 7 capacitors. ,86e6f450b8cc469628ba70bf2947b049The output stage of the LF amplifier is made on KT315A transistors according to a push-pull transformer circuit. ,86e6f450b8cc469628ba70bf2947b049In comparison with other radios, the printed circuit board is reduced here due to the use of a microcircuit with dimensions of 26 x 22 x 13 mm. ,86e6f450b8cc469628ba70bf2947b049The use of the 0.5GD-21 loudspeaker improved the acoustic parameters and made it possible to increase the rated output power to 220 ... 250 mW. ,86e6f450b8cc469628ba70bf2947b049Powered by 6 elements of the "316" type. ,86e6f450b8cc469628ba70bf2947b049The dimensions of the radio are 195 x 95 x 50 mm. ,86e6f450b8cc469628ba70bf2947b049Weight about 700 g. Due to technical problems at the end of 1972, the radio was removed from the assembly line, and the production of the Selga-402 radio was continued.,86e6f450b8cc469628ba70bf2947b049,null,ru,null,null,null,null