It was certainly only large cars that had enough electric current for the first Blaupunkt car-radio in 1932, then this was big, did not fit into the dashboard and needed a great deal of electric power for it's valves (vacuum
tubes). The radio has to pick up oscillations (waves) and then process them. If e.g., nowadays Bluetooth functions in the region of between 2,402 to 2,480 GHz, one should be aware that 1 Hz means one-, and 1 GHz
means 1 billion oscillations per second.
|Frequency -> Number of periods (repititions)|
In the beginning it wasn't quite that fast. At that time, the preferred medium-wave transmission was broadcast at approx. 1 MHz (1 million oscillations per second). Thus, after the war, the ultra-short-wave (FM) was 100
times faster. If you consider the fact, that only young people can even hear the sounds in the regions of up to 20 KHz (20.000 Hz), you can easily conclude that:
1. The medium-wave frequence must be modulated
down by the factor 50 - 100,
2. the FM-frequence by the factor 5.000 to 10.000,
3. and that the FM-frequence can deliver a far better sound-quality.
Radio reception in the motor-car probably all started with a large, heavy casing, containg receiver, battery with liquid catholyte and speaker. It was almost impossible to switch on the device during the journey, because a
long aerial wire had to be laid. The position of this, by the way, was altered, for the first real radios, e.g., to the inside of the ceiling, where it was laid out similarly to the under-floor heating of today.
Of course the shielded, sheet-metal covered receiver was still far too bulky for the dashboard. It had to be installed in the leg room and accessible from the driving seat and connected, e.g., through Bowden cables with
the operating device (see figure 1). Because the power-saving transistor had not yet been invented, high-voltage warm-up valves were used, their electric
power requirements could hardly
be satisfied when the engine was switched off. Even with a running engine it was difficult due to the available weak DC generators.
Apparently, the first car radios appeared around the period of 1904/5. There are also a number of reports about a radio that was installed in the model T Ford. The mass production of the car radio started in the USA, probably only after 1927, leading however, within 6 years, to a proliferation of approx. 100,000, in Europe
this number was aimed at only after 1947. It began with the introduction of the Blaupunkt AS 5 which cost 465 Reichsmark (RM 465,-) at the Radio Trade Fair in 1932. In the meantime, more frugal tubes had been
developed, with heating that was laid out especially for the demands of motor-cars at that time.
If, at that time, an additional battery was still necessary for the high voltage, the devices had now become smaller because the high tension could be produced from the battery voltage with the help of a DC-converter.
The reduction in size progressed, until in 1949, for the first time, the integrated radio/operation element was successfully installed into the dashboard. This however, was still connected by cables to a separate device.
From 1957 until about 1961 the valves were replaced by transistors, which further reduced the necessary installation space and also the requirements.
From then onwards it was, in principle, all about the internal development and refining of the car radio. Channel-buttons (1951) and certainly the VHF (FM) reception (1952) was part of it, but also the channel-search
mode (1953), the cassette cartridge drive (1968) and stereo broadcasting (1969). Even before the first micro-processors were introduced, there were fairly accurate traffic announcements (1976). Then, however, the
display started undergoing a radical change, at first with just digital text and later also more and more graphic representation. However, having almost reached day technology, perhaps the CD player (1985) should be
mentioned as an important step in the history of the car radio. 05/13