[Elecraft] Another urban legend: clicks needed for readability

[Vic Rosenthal]

Guy Olinger, K2AV wrote:

> Wayne's solution, by its very simplicity, proves that there's really
> no excuse for not fixing the clicks. It will also very quickly put an
> end to the urban legend that signals have to have a sharp wideband
> click on them for readability.

Urban myth is right!  Keep in mind that the effect of narrowing the 
bandwidth in your receiver is to round the edges of the received signal 
(that this must be so is obvious from the fact that what makes the edges 
of a pulse sharp is the out-of-band energy which is filtered out by the 
selective filter).  I haven't done the math, but I bet that a 
square-wave signal will probably sound the same as a modified K2 when 
the receiver filter is about 400 Hz. -- at least, if you are listening 
on the signal frequency.

In addition, as Guy points out, when you are receiving a signal right at 
the noise level, you don't get the out-of-band energy anyway (since it 
is weaker than the main signal) and so you CANNOT HEAR the sharp edge of 
the code elements!  That's why W8JI's DXers couldn't tell the difference.

To put it another way, the only time you can distinguish a hard from a 
soft signal is when it is loud and you are using low selectivity.  And 
in this case there isn't a problem with readability (unless the code 
speed is high enough to start to run the elements together, which we've 
seen MAY POSSIBLY occur above 60 wpm).

-- 
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco