Portable transistor radio "Sputnik".

Portable radio receivers and radios on p / p.DomesticThe portable transistor radio "Sputnik" has been producing the Voronezh Radio Plant since the spring of 1957. Sputnik is one of the first portable transistor receivers in the USSR. The receiver is assembled according to a superheterodyne circuit with 7 transistors, and only three transistors are used in the LF amplifier. The peculiarity of the receiver is a low-voltage power supply, only 5 V, although the performance remained in the range of 4.7 ... 5.5 V, which caused the use of batteries, they are known to keep the voltage practically unchanged, giving only current. Another feature of the receiver was the presence of a solar battery in it, which recharged the batteries from the scattered or direct light of the sun when the receiver was turned off, and from direct sunlight even during transmission pauses, allowing it to work without discharging the batteries. The receiver is designed for loud-speaking reception of radio stations operating in the LW and MW range. Sensitivity when working with an internal ferrite antenna 2000 µV for LW and 1000 µV for MW. Adjacent channel selectivity is 26 dB for LW and 20 dB for MW. On the mirror channel 20 dB. IF - 465 kHz. When the input signal changes by 30 dB, the automatic gain control will change the output voltage by 6 dB. Rated output power 100 mW, maximum 130 mW. The range of sound frequencies reproduced by the 0.25GD-1 loudspeaker is not more than 250 ... 3000 Hz. Average sound pressure 1.5 ... 2.0 bar. Power supply from four small-size zinc-cadmium batteries TsNK-0.4 with a total voltage of 5 V. The duration of continuous operation from freshly charged batteries is 50 hours. The receiver case is made of dried pine wood, impregnated with an alcoholic cellulose solution and covered with decorative plastic. The dimensions of the model are 185х125х49 mm, weight with batteries is 950 g. The retail price of the model is 514 rubles (in 1957 money). The Sputnik receiver was experimental and small-scale (~ 1000) pieces). In 1959, the receiver was modernized according to the electrical circuit, but did not go into serial production. In terms of design and parameters, the radio receiver was very successful and remained the leader among subsequent similar radio receivers for several more years.