In computer space 4ms is an eternity. I do wonder what is going on there. And also hope the K4 fixes it. Thanks again for the scope shot.
Ed / w2rf From: Bob Wilson, N6TV <n...@arrl.net> Sent: Friday, June 12, 2020 10:37 AM To: Elecraft Reflector <Elecraft@mailman.qth.net> Cc: E.H. Russell <e...@qrv.com> Subject: Re: [Elecraft] CW rise time setting The plot in the QST review of the K3S shows the delay between "key closure" (the KEY jack of K3S) and RF out. My plot shows the delay between "amp relay closure" (the KEY OUT jack of K3S) and RF, which is more critical. Most folks assume there will be no delay between KEY closure and KEY OUT closure, but there is an extra delay (of about 5 ms, minimum) in the K3S. The same applies to PTT IN closure and KEY OUT closure; that is, there is an unexplained fixed 5 ms delay in the K3S, probably due to slow firmware logic testing for TX Inhibit or an intentional enforcement of some minimum delay in RF output. Most radios close KEY OUT immediately upon key closure of either the KEY jack or the PTT IN jack. The K3 does not; it "hesitates" before closing KEY OUT. I'm also hoping the K4 will eliminate this unusual behavior. 73, Bob, N6TV On Fri, Jun 12, 2020 at 3:23 AM E.H. Russell <e...@qrv.com <mailto:e...@qrv.com> > wrote: Bob, Thanks for the scope shot and info. I compared the waveform to the QST K3S review, which seems to show a little over 10ms before RF appears. Is this because they used different settings? Will be interesting to see how the new radio CW looks in time and frequency domains. Also how the turnaround latency is managed. Tks, 73 Ed w2rf From: Bob Wilson, N6TV <n...@arrl.net <mailto:n...@arrl.net> > Sent: Thursday, June 11, 2020 2:05 PM To: Elecraft Reflector <Elecraft@mailman.qth.net <mailto:Elecraft@mailman.qth.net> > Cc: E.H. Russell <e...@qrv.com <mailto:e...@qrv.com> > Subject: Re: [Elecraft] CW rise time setting On Mon, Jun 8, 2020 at 12:31 PM E.H. Russell <e...@qrv.com <mailto: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, Per your request, I am publishing this scope screen capture which plots the CW rise time in my K3 with the KSYN3A synthesizer upgrade. It's about 4 ms from 0 RF to full RF (2 ms per horizontal division): https://www.kkn.net/~n6tv/N6TV_K3_Ser_1494_FW_05.64_TX_DLY_8_CW_QRQ_OFF.png The vertical markers are there to illustrate that CONFIG:TX DLY nor 008 provides only about 6 ms of RF delay after "KEY OUT" goes to ground, not 8 ms, and there is jitter in that delay as well (not shown). If CW QRQ mode is enabled, the delay drops to about 4.6 ms and the TX DLY setting is completely ignored. This was discussed here two years ago. See this post for suggestions on how to avoid hot-switching a non-Elecraft amplifier driven by a K3 or K3S: http://elecraft.365791.n2.nabble.com/Default-K3-transmit-delay-may-be-too-short-for-slow-QRO-amplifiers-td7641779.html 73, Bob, N6TV ______________________________________________________________ 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
