[AMRadio] AM Transmitter "quality"
Joe Hankins
joe_hankins at lexcominc.net
Tue Sep 15 14:11:05 EDT 2009
I really don't care whether people chose to modify their old AM
transmitters to "improve" sound quality, as they can do whatever they
want with their radio. What does bother me a little is when people use
words like "nasty" and "awful" to describe the audio quality of some
classic transmitters, as if thedesigners of the day were not smart
enough to design a decent transmitter.
At the time these transmitters were built, the goal of amateur pone
operation was effective radiotelephone service. Human speech falls into
the range between 300 and 3000 Hz. There are sounds outside this range,
but they do not contribute to intelligibility. So, in order to make the
best use of the power available, the bandwidth didn't need to be more
than 4Khz. The next logical step in the quest for efficient use of
available power was SSB, which has an equally "nasty" sound but does the
intended job quite well.
By modifying a transmitter to increase the audio bandwidth, all that is
being done is to get it closer to the commercial broadcast transmitters
of the day, which needed much greater bandwidth to handle music.
Joe
KN4JH
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