[Elecraft] Fwd: New Sherwood report

[Don Wilhelm]

Barry,

What is being said is that the *shape* of the rise and fall times is 
important, not the absolute timing of the rise of fall time.
In other words, the transitions of the waveshape are the important 
parameters - if the transitions are smooth rather than angular, they are 
less likely to generate sidebands.

Of course there are practical limits, but the CW sidebands cannot be 
judged on risetime alone.

Most likely, if the shaping with a 4 ms. rise time is such that 
excessive sidebands are produced, then at 1 ms, the sidebands will be at 
least as wide, if not wider unless the keying waveshape is changed.  But 
-- while I suspect that, I could not claim it unless it were measured.

73,
Don W3FPR

On 12/2/2010 7:32 AM, Barry N1EU wrote:
> Are you saying that wide sidebands measured with the rig at 4msec rise-time
> are probably not going to be even wider with the rig at 1 msec rise-time?
>
> Barry N1EU
>
>
> Kok Chen wrote:
>> On Dec 1, 2010, at 5:59 PM, Barry N1EU wrote:
>>
>>> It's absolutely amazing, after years of Yaesu being called out and doing
>>> nothing about key clicks in their rigs, that they would bring out a radio
>>> (FT-5000) and provide the user the ability to reduce the cw rise-time to
>>> 1 msec (menu mode, cw group, 063 A1A Shape).  Just incredible.
>> The rise time by itself is not the important factor --  what is much more
>> important are first and second order discontinuities, and even higher
>> order discontinuities.
>