[Amps] Slow start-up of Amps on CW

Pete Smith N4ZR pete.n4zr at gmail.com
Tue Mar 12 21:24:53 EDT 2024


I think this thread is drifting off-topic.  We're not talking about the 
waveform of CW, but how long it takes after PTT before the KPA-1500 is 
ready to amplify incoming signals.  I've been there - at first my N was 
getting trimmed into a non-character, so I now have a 50 ms. delay in my 
Winkeyer (which controls PTT) to prevent that.

73, Pete N4ZR

On 3/12/2024 7:52 PM, Jim Brown wrote:
> On 3/12/2024 2:40 PM, Robert W5AJ wrote:
>> Best I can tell, FTdx10 CW with 6ms rise time is in par with K3 
>> looking at QST In Depth review
>
> Fast rise time CAUSES clicks; beginning with the first K3, Elecraft 
> uses a carefully shaped keying waveform that they call "sigmoidal," 
> (which I've heard described as a raised cosine) to provide nice sharp 
> keying without clicks. I've heard that after a bad ARRL review for for 
> their 6500 series rigs, they adopted that shaping or something like it.
>
> But rise time is the wrong thing to measure -- a spectral plot showing 
> sidebands with a string of dits shows where the bodies are buried.
>
> Likewise, modulation with a sine wave, or even an IMD pair of sine 
> waves, fails to expose splatter caused by processing like Yaesu is 
> (was?) doing in those rigs.
>
> Splatter running VHF/UHF rover is far less likely to cause QRM except 
> during band openings on SSB.
>
> FWIW -- I love my K4, but am still quite happy with my 2008-vintage K3 
> with upgraded synth.
>
> 73, Jim K9YC
>>
>> It is interesting to watch the CW signals now with the BandScope
>> more so during CW contest!
>> Still own the K3 but I'm not likely to sport (Buy) a K4
>> The FTdx10 is ideal rig to carry on the 50Mhz rover trips, gets me 
>> band scope & built in sound card
>>
>> 73 Robert W5AJ
>
>
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