It’s closer to 4 ms. Wayne N6KR
---- elecraft.com > On Jun 8, 2020, at 12:32 PM, E.H. Russell <e...@qrv.com> wrote: > > I suppose shaping of the curve corners removes harmonics introduced by the > abrupt transitions, allowing an accelerated ramp inbetween. But does this > really reduce the total rise time to 2.5ms? It seems that the softening > process must take some time. Wish I had a K3 here to scope against other > radios. Anything published out there? > > > > Ed / w2rf > > > > > > > > From: Alan Bloom <n...@sonic.net> > Sent: Monday, June 8, 2020 3:15 PM > To: E.H. Russell <e...@qrv.com> > Cc: 'Elecraft Reflector' <Elecraft@mailman.qth.net> > Subject: Re: [Elecraft] CW rise time setting > > > > In the "good old days" key shaping was done simply by adding a capacitor to > the key line or equivalent. That results in an exponential rise and/or fall > time, which is not optimum, so the time constant had to be set pretty slow to > avoid key clicks. Typically 5-10 ms. 10 ms results in "mushy" keying, > especially at high CW speeds. > > > > Raised-cosine key shaping is close to optimum and is easy to implement with a > DSP. It allows faster rise/fall times without key clicks. I assume Elecraft > is using something like that. > > > > Alan N1AL > > > > > > > > > > > > On 2020-06-08 12:51, E.H. Russell wrote: > > I'm used to CW rise times in th 4-7ms range. Is this 2.5ms arrived at by a > different metric? Is the curve added by sigmoidal shaping somehow excluded > from the measurement? > > > > Ed / w2rf > > > > > > > > -----Original Message----- > From: elecraft-boun...@mailman.qth.net > <mailto:elecraft-boun...@mailman.qth.net> <elecraft-boun...@mailman.qth.net > <mailto:elecraft-boun...@mailman.qth.net> > On > Behalf Of Richard Stutsman > Sent: Monday, June 8, 2020 1:31 PM > To: David Gilbert <ab7e...@gmail.com <mailto:ab7e...@gmail.com> > > Cc: Elecraft Reflector <Elecraft@mailman.qth.net > <mailto:Elecraft@mailman.qth.net> > > Subject: Re: [Elecraft] CW rise time setting > > > > Yes, I would regard a 2.5 msec rise time (using appropriate sigmoid > > shaping) to probably be ideal, in which case I would have no desire to > modify or shorten it. I'll bet it will sound even better than a Drake or a > Ten-Tec! > > > > I hereby withdraw my previous request/opinion. > > > > Rick N6IET > > > > On Mon, Jun 8, 2020 at 10:27 AM David Gilbert < <mailto:ab7e...@gmail.com > <mailto:ab7e...@gmail.com> > > ab7e...@gmail.com <mailto:ab7e...@gmail.com> > wrote: > > > > > > > You don't need to generate clicks to have a crisp CW tone. Elecraft > > > > > > uses a pretty much optimally shaped waveform (some version of a cosine > > > > > > function) and if I remember correctly the rise time is only about 2.5 > > > > > > msec, although I could be wrong about that last part. And while you > > > > > > may be careful not to use short rise/fall times when the band is > > > > > > active, in the past there have been folks on the contesting reflector > > > > > > who openly admitted they purposely generate clicks by shortening the > > > > > > rise/fall times to give themselves elbow room. I will always > > > > > > appreciate that Elecraft doesn't give those miscreants the means to > > pollute the band. > > > > > > 73, > > > > > > Dave AB7E > > > > > > > On Mon, Jun 8, 2020 at 9:23 AM Richard Stutsman < > > <mailto:rast...@gmail.com <mailto:rast...@gmail.com> > rast...@gmail.com > <mailto:rast...@gmail.com> > wrote: > > > > > > I for one would like to have some control over the rise/fall times. > > > > > > > > > > You want the cleanest (narrowest) of CW signals when operating on a > > > > > > crowded band or in a contest - unless you're a rare DX station. Most > > > > > > of my operations are 22wpm rag chews on very uncrowded bands. We're > > > > > > often the only discernible signals on an entire CW band. And > > > > > > conditions are often noisy with deep QSB. Why not allow those of us > > > > > > operating in those circumstances to shorten the rise times a bit, > > > > > > which makes it easier to copy in noisy conditions, when any close-in > > > > > > clicks or thumps aren't going to bother anybody? Copying a 'soft' > > > > > > weak CW signal is like trying to read a 'crisp' signal that's an > > > > > > entire S-unit weaker, IMO. > > > > > > > > > > My TS-590sg let's me do that, and I love it! > > > > > > > > > > Will the K4 sound as good as a Drake T4C? (Just askin'.) > > > > > > > > > > Rick N6IET > > > > > > > > > > N4ZR wrote: > > > > > > > > > > Will the K4 have options for setting CW rise and fall times...? > > > > > > Hi Pete, > > > > > > Probably not. We've always been very careful to ensure our rigs > > > > > > have an exceptional clean, click-free CW signal. (Third-party > > > > > > testing bears this > > > > > > out.) Minimizing the bandwidth requires a very specific rise/fall > > > > > > time > > > > > > and > > > > > > a hand-crafted sigmoidal shaping function in DSP. > > > > > > Colonel Sanders closely guards his fried chick recipe, Mrs. Fields > > > > > > won't reveal what's in her chocolate-chip cookies, and only > > > > > > selected firmware monks--sworn to secrecy--are privy to Elecraft's > > > > > > keying envelope coefficients :) 73, Wayne N6KR > > > > > > ______________________________________________________________ > > > > > > Elecraft mailing list > > > > > > Home: <http://mailman.qth.net/mailman/listinfo/elecraft> > > http://mailman.qth.net/mailman/listinfo/elecraft > > > > > Help: <http://mailman.qth.net/mmfaq.htm> > > http://mailman.qth.net/mmfaq.htm > > > > > Post: <mailto:Elecraft@mailman.qth.net <mailto:Elecraft@mailman.qth.net> > > mailto:Elecraft@mailman.qth.net <mailto:Elecraft@mailman.qth.net> > > > > > > > > > > This list hosted by: <http://www.qsl.net> http://www.qsl.net Please help > > support this > > > > > email list: <http://www.qsl.net/donate.html> > > http://www.qsl.net/donate.html Message delivered to > > > > > <mailto:ab7e...@gmail.com <mailto:ab7e...@gmail.com> > ab7e...@gmail.com > <mailto:ab7e...@gmail.com> > > > > > > > > ______________________________________________________________ > > Elecraft mailing list > > Home: <http://mailman.qth.net/mailman/listinfo/elecraft> > http://mailman.qth.net/mailman/listinfo/elecraft > > Help: <http://mailman.qth.net/mmfaq.htm> http://mailman.qth.net/mmfaq.htm > > Post: <mailto:Elecraft@mailman.qth.net <mailto:Elecraft@mailman.qth.net> > > mailto:Elecraft@mailman.qth.net <mailto:Elecraft@mailman.qth.net> > > > > This list hosted by: <http://www.qsl.net> http://www.qsl.net > > Please help support this email list: <http://www.qsl.net/donate.html> > http://www.qsl.net/donate.html Message delivered to <mailto:e...@qrv.com > <mailto:e...@qrv.com> > > e...@qrv.com <mailto:e...@qrv.com> > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net <mailto:Elecraft@mailman.qth.net> > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to a...@elecraft.com <mailto:a...@elecraft.com> > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to n...@elecraft.com ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
