Radio receivers '' TM-7 '' and '' TM-8 ''.

Amplifying and broadcasting equipmentThe radio receivers "TM-7" and "TM-8" have been produced since 1938 by the Aleksandrovskiy radio plant No. 3. The radio receivers "TM-7" and "TM-8" are intended for use on broadcasting radio broadcasting centers. A small number of receivers were also sold in retail. As to the receivers of broadcasting units, the following requirements were imposed on them: with good sensitivity and selectivity, at the output, have a power sufficient for transmission over the air or cable line and excitation of the unit's preamplifier. For this, an output power of the order of 200 ... 250 milliwatts is sufficient. Since the receivers are designed to receive broadcasting stations at any points of the USSR, they must be all-wave. By the time these receivers were released, the SVD-M receiver was the most suitable in terms of its performance. On its basis, these receivers began to be produced. This explains the fact that both receivers, both in scheme and in design, are almost identical with the SVD-M receiver and have approximately the same parameters. The main difference is that they lack the last stage of power amplification. They differ from each other in that the TM-8 is designed to be powered from the AC mains, and the TM-7 is powered by rechargeable batteries, therefore it does not have a rectifier unit. In addition, in order to save batteries in the circuit of the TM-7 model, there is no optical indicator of the 6E5 lamp setting, which is available in the TM-8 receiver circuit. The receivers are decorated in iron boxes, painted black on the outside and aluminum paint on the inside. The chassis is similar to the SVD-M chassis and is mounted in cases with rubber shock absorbers. The top cover of the case opens to provide access to the top of the chassis. The back wall of the case is perforated (for ventilation). On the front side, the control knobs are brought out: this is a range switch, a tuning knob, a volume control and a treble tone. In the TM-8 receiver, the last knob is also a power switch. On the back side are the antenna, ground, pickup sockets, as well as the receiver output sockets. The output power of both receivers for an impedance of 600 ohms and with a 5% clear factor is 200 mW. The IF is 445 kHz. The range of received radio frequencies and waves: A - 150 ... 400 kHz (2000 ... 750 m). B - 540 ... 1500 kHz (556 ... 200 m). Г - 3500 ... 9000 kHz (85.7 ... 33.3 m). D - 8.2 ... 18 MHz (36.6 ... 16.7 m). High frequency sensitivity at 30% modulation and 0.02 watt output power, on all ranges about 50 μV. LF sensitivity (voltage at the pickup sockets) at a nominal output power of 200 mV. Attenuation of the signal when the receiver is detuned by 10 kHz: on the A, B bands by 10 times, D, D by 5 times. Attenuation of the specular interference on the A, B bands by 1000 times, D, E by 55 times. The frequency response at low frequency from the input of the pickup to the output of the radio receiver is straightforward in the range from 60 to 6000 Hz. The TM-8 receiver consumes 75 watts. The `` TM-7 '' receiver requires 6.5 V in heat, at a current of 2.65 A, and at the anode of 240 V, at a current of 75 mA.