[Elecraft] [K3] K3: killing RX key clicks

[GW0ETF]

My take is that in the extreme cw is an AM signal modulated by a pure square
wave and as such prduces infinite odd order harmonics which will appear as
sidebands/clicks. Filtering reduces the extent of the sidebands and smooths
the square wave shape particularly rise and fall times but you will still
have sidebands equivalent to 7th or 9th harmonics..? This would represent
the ideal and you would have to be very close to the signal to hear the
sideband energy - a bit of work on the calculator will tell you where the
7th or 9th harmonics would appear for a string of dits depending on the
keying speed etc.

But I'm convinced that most bad clicks are actually a result of spurious
switching spikes at the 'corners', often at the trailing edge and can
produce sideband energy *way* out from the fundamental. This is nothing to
do with the inherent physics of the cw signal and as such is curable.

73, 

Stewart Rolfe, GW0ETF




Ron D'Eau Claire wrote:
> 
> It's basic physics, Jim. A keyed signal is amplitude modulated and an
> amplitude modulated signal produces sidebands. 
> 
> ......................
> 
> On CW those sidebands sound like clicks. 
> 
> Ron AC7AC
> 
> 

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