Three-program receiver `` Riga '' (RTV-64).
Three-program receivers.The three-program receiver "Riga" (RTV-64) since 1964 has been produced by the Daugavpils enterprise OTs-78/3. Production at the Correctional Labor Institution "White Swan", Latvia. PT "Venta" (RTV-61) was used in the networks of three-program wire radio broadcasting. Their relatively high price (20 rubles) became an obstacle to the wide development of three-program broadcasting. In addition, they had circuit and design flaws. (RTV-64), which replaced them, has a good appearance and high reliability. Schematic and constructive solutions made it possible to reduce its cost to 11 rubles 90 kopecks, the retail price also decreased to 15 rubles. The loudspeaker had a different name in various documentation, such as: GTV-64 and ATV-64, which may be interpreted as Loudspeaker (G) and Subscriber (A). The receiver has jacks for connecting a tape recorder for recording. The first program in multi-program broadcasting networks is transmitted over the LF channel, and the second and third over the HF channels with carrier frequencies of 78 and 120 kHz, respectively. For the 2nd and 3rd programs, the PT has the following indicators. Rated output power 150 mW. The sensitivity is 170 mV, with an input impedance of 800 ohms for the working channel and 5 kΩ for the adjacent ones. The audio frequency band is 100 ... 6000 Hz with unevenness of 6 dB, taking into account the correction of the frequency response of the transmitters. THD - 6% at a frequency of 100 Hz and 3% at 200 ... 4000 Hz. Background level -40 dB. Power consumption from the network is 4.2 W. The loudspeaker is equipped with a 1GD-6 dynamic loudspeaker. The adjusting controls are located on the front panel. The mains fuses are located inside the machine for safety reasons. The PT was modernized several times, while the electrical circuit remained the same, and the changes concerned the design. PTs were produced until 1970.
