Hi all !
Very OFF TOPIC,.. but I risk beeing flamed or blamed:
My late father was a well known electronics and radio specialist here in
Norway, running his own company. Off the record he told me a few things
he always wondered about. One thing was that "in the old days" they
always experienced a lot more unwanted rectification (detection) of
AM signals in MECHANICAL devices like rain gutters, downpipes and so
on, giving rise to actual Audio Output from these non-electronic things.
He claimed that near QRO AM transmitters people used to hear the news
from the strangest of things... He had also noted that in "modern days"
this did not seem to happen very often. This gives rise to Q no. 1:
What changed,- if anything ??
Now to part 2 :
AM modulation is generated by mixing a carrier and an audio signal in a
nonlinear process. If it was 100% linear, according to the maths no
modulation would result, and in the output you would find an amplified
audio signal and an amplified but unmodulated carrier
What if you actually succeeded to modulate in a linear stage? I KNOW
that this is mathematically impossible by todays maths, but let your
thoughts flow freely, and picture a variable, linear resistance bridge
that varies with the audio drive. To avoid traps please figure this in the
antenna output of a transmitter. The resistance bridge is modulating a
clean RF carrier while maintaining a constant load ( like an ideal attenuator)
It responds to the full audio bandwith. Avoid the statement that a varying
resistance
can not be considered linear,- or state that as a fact,- if you like.
Clearly and surely if you tried to analyze this "AM" signal with modern
methods it will show sidebands. Analyzers and receivers use nonlinear
mixers and/or detectors. But if you could analyze it with a linear detector
??----
a WHAT ??? !! Well,- i AM ( :-) ) educated in electronics, but I have the
ability to "let my brain run wild " :-)
Do You ?
I will standby for a while and watch any message !
and finally: How is part 1 of this message and part 2 connected ?
Yours
LA7SL " Peter"
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"I don't suffer from insanity. I enjoy every minute of it"
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