Initially, radio transmissions were broadcast on frequencies
ranging from 100kHz to 1500kHz (ie, on wavelengths from 3000 metres to 200
metres, respectively). However, there were some high-power transmissions below
This view of the AWA C103/43 converter shows the layout on the top of the chassis. All parts are readily accessible, making it easy to service.
Basically, all "important" transmissions were licensed or
permitted to operate in this general frequency range. By contrast, those "pesky"
experimenters and amateurs were permitted to use any of the so-called "useless"
frequencies above 1500kHz. Because of this frequency allocation, they were not
expected to be able to contact each other over long distances but they quickly
proved the authorities wrong!
Radio transmissions for entertainment commenced during the
early 1920s and quickly became popular. As a result, radio manufacturers and
home constructors developed receivers to operate on both the long-wave and
medium-wave bands (100-1500kHz). At the time, there was no reason to have radios
capable of tuning above 1500kHz, since those frequencies were used only by the
In any case, the components used in radios at the time were
generally unsuitable for frequencies above 1500kHz, as was the layout of the
sets. That didn’t deter the experimenters, however. They immediately set about
making the most of the frequencies that they were permitted to use and began by
experimenting with ways to improve both the stability and the performance of
their receivers and transmitters.