Meiduo 美多 Unknown Transistor Radio  ID = 176333

click here for the original German post

Translated from  radio und fernsehen  17-1959  S. 540-541  o.A.  "Rundfunk und Fernsehen in China" (Report from  Leipzig Spring Fair 1959),

by  M Burgess

Please notice:  

the similarity of the Meiduo radio circuitry to the early  Sony / Gendis TR-72  circuitry is obvious.

 

Radio and Television in China

...In addition to some big factories in the People's Republic of China, many small businesses are manufacturing radio receivers. The most important include:

The Radio Factory in Shanghai;
The Peony plant in Beijing;
And plants in Nanjing and Tianjin.

The plant in Shanghai is located in a large newly constructed complex. Some particularly interesting models from this establishment are shown this year at the Leipzig Spring Fair:

a radiogram, a large table radio with four speakers featuring four wavebands and a ferrite antenna and a portable radio.

The first transistor model radio was developed last year. Its production could be expected to commence this year when the necessary transistors are available in sufficient quantities. This receiver is a fully transistorized medium-wave superhet with a ferrite antenna and gain control using seven transistors and two diodes (Figs l and 2).

Special attention has been given to the construction of this model to increase its sensitivity and to miniaturise its components compared to previous Chinese sets. This requirement led to the use of new components developed in China, such as ferrite rods, ferrite pot core IF transformers, ceramic capacitors, miniature carbon film resistors and small variable tuning capacitors. Notably this receiver was manufactured with a printed circuit board...

...Technical Data
Superthet transistor portable
Wavelength: 530 kHz-1600 kHz
Transistors: 2T51 (mixer), 2x2T51 (IF gain), 2x2T61 (AF-amplification), 2x2N43 push-pull output stage
Intermediate frequency: 455 kHz
Sensitivity: <1000 µV/M, Output power: 50 mW maximum
Power source: 3 D-cells 1.5 V, Power consumption: ~ 33mA...

                                     

(click on image for full scale schematic)

Reference

radio und fernsehen  17-1959  S. 540-541  o.A., "Rundfunk und Fernsehen in China"
(Bericht von der Leipziger Frühjahrsmesse 1959), extract

 

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