Portable radios

Portable radios were made since the end of the 1920s, just as it was possible to make a compact design with low antenna quality demands. The so-called battery tubes were used, these had a much lower power consumption than the types used for mains operation, but also had a much lower power output. Tabletop battery radios were also common, because some parts of the country did not have electric mains connection well after the end of the World War II. Battery tube radios required an anode battery composed of many small cells connected in series. Its voltage was usually 67,5 or 90 V. The current consumption from this battery was relatively small, but its price was high. Moreover, the radio would require a heater cell that would supply a small voltage, but large current - a lead (2 V) or nickel (1,2 V) rechargeable cell or zinc-carbon (1,5 V) primary cell. The climax of battery tube radio production were the purse-sized radios of the second half of the 1950s, whose size was similar to the newer transistor radios. Some foreign companies even managed to produce a pocket-sized tube radio. The common characteristic of battery tube radios was their expensive operation, the batteries had short lifetime. The radios usually consumed constant amount of power regardless of the output volume.

Since 1958, transistor radios were produced in Czechoslovakia. These have brought a revolution into this category of products - they required just few volts instead of the 90 volts with the same current consumption and the heater battery was not required at all. A few cells could power the radio for hundreds of hours of operation. The power consumption was dependent on the output power, so it was possible to save the batteries by low volume listening. FM transistor radios were made since the 1960s, modern colorful plastics are used. The 1970s bring integrated circuits that enable further size and power usage reduction. The colorful cabinets are pushed out by angular, grey designs. The 1980s see the advance of stereo radios with a built-in cassette recorder and many functions. Apart from the domestic products, Soviet radios of all size and price categories were widely imported. These can be generally regarded as very well designed.