Hi Nils,
I'm not familiar with the hardware on your side of
the pond but, over here the prefernce is to employ
plastic for the pipes & gutters which might explain
the recent decline in incidental reception. :)
73 & Good afternoon,
Marv WC6W
http://wc6w.50webs.com/
--- Nils Petter Pedersen <la7sl@online.no> wrote:
>
>
>
> 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"
> ____________________________________________
>
> "I don't suffer from insanity. I enjoy every minute
> of it"
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