Hi, I applaud you guys putting numbers to the issues. In my working life our engineering department's slogan was: "The numbers will set you free." I'm sure Dilbert agrees!
very best regards Rob AB7CF On Wed, 14 May 2008 17:31:22 -0400 Jerry Flanders <[EMAIL PROTECTED]> writes: > Good that you could measure the numbers there, Ed. > > I don't know the numbers for any of my rigs, but I just did a > quickie > listening test and the K3 definitely gives me audible band noise > conditions at 35. I am new to the K3 and don't really know how to > get > the optimum from it yet - it probably does as well as the official > Elecraft claim: "With the internal keyer running at an indicated 50 > > WPM, you can hear band activity between dits while using the > narrowest filters. " (From the Elecraft website K3 FAQ). > > The K3 lets me dial in a specific speed, so it was easy to set it to > > 35 for tests. Not so the ICOM 756PRO3, which I also tested. I tried > > it at what I believe is at least 30 WPM, and I could hear band noise > > on it also. The ICOM uses reed relays. > > I had an IC-7000 in operation for a while a few weeks ago and > satisfied myself that I could hear band conditions between dits with > > it also, but didn't record any WPM numbers. It was probably in the > 30 > WPM range. > > W0QE has made keying time measurements on a number of modern rigs > (he > was interested in switchover timing for amplifier QSK use) at > http://www.bnk.com/w0qe/amplifier_timing.html . Some of his data may > > be usable to estimate possible QSK speed limits per your > calculations, but the receiver recovery time is not included in his > report. > > I hope someone with a better "lab" than mine can put some of these > rigs to the test as you request and actually record and publish the > > resulting audio. That would help popularize full QSK, I think - when > > you have heard/used the real thing, you want nothing less. > > Thanks for the work you have done to improve PowerSDR. > > Jerry W4UK > > At 01:11 PM 5/14/2008, Ed Russell wrote: > >Jerry has brought up an important point. We CW ops believe true > QSK > >means hearing between dots at high speed. I thought so myself until > I > >began looking closely at the performance of box-based rigs. > > > >There is an easy calculation that shows why true QSK is difficult: > > > >R/T + T/R - ES = Band Sound > > > >where > > > >R/T is time it takes to mute receiver and begin transmitting > >T/R is time it takes to stop transmitting and fully activate > >receiving > >ES is element spacing > > > > > >ES is 30ms at 40wpm > >ES is 40ms at 30wpm > >ES is 60ms at 20wpm > > > >Hit the key. It takes about 10-15ms to get a waveform started. > >Release the key. It takes about 15-20ms minimum for T/R > turnaround; > >most rigs take 30 or more. That means in the best possible case > R/T > >plus T/R turnaround takes 25ms. > > > >I measured the response of my 950SDX: > >R/T = 13ms > >T/R = 19ms > > > >That means no Band Sound at 40wpm. I measure 10ms of Band Sound at > >30wpm, but subjectively that isn't enough to call useful. > > > >The 950SDX is an old radio, you might say. But if you look at the > >ARRL reviews the numbers are equal to or better than newer rigs. > So, > >what is the rig that can really do QSK? The K3? Maybe, but it's a > DSP > >rig too. > > > >Send me a tape :) > > > >73 Ed W2RF > > > >On 14 May 2008 at 11:59, Jerry Flanders wrote: > > > > > Thanks, Ed. BTW, what you describe as QSK is usually referred to > as > > > "semi break in", or "Semi QSK" by CW ops. There is a world of > difference. > > > > > > For the guys and gals out there who may not understand the > > > distinction, CW ops refer to QSK as the ability to actually > hear > > > activity on the band between dits at a reasonable speed. Modern > > > radios that actually do true QSK can do it at 30-50 WPM. > > > > > > I look forward to purchasing another 5000a (first was sent back > for > > > poor CW performance) if and when new software actually allows it > to > > > perform to this standard. I am pretty sure the 5000a hardware > will > > > allow this, but the following quote from Frank Brickel's April > 26 > > > post in the then-current "CW QSK ability" thread eliminated my > hope > > > that the current PowerSDR could _ever_ provide QSK: "I think > this > > > line of discussion has run its course of usefulness. > Development > > > effort is being focused on doing it right, not patching the > current > > > system, which is basically unfixable in a systematic and > > maintainable way. " > > > > > > If I understand Frank correctly, we will not see what CW ops > call QSK > > > in PowerSDR/Windows. Ever. > > > > > > Jerry W4UK > > > > > > At 07:34 AM 5/14/2008, Ed Russell wrote: > > > >Hi Jerry, > > > > > > > >It's a 5k. I don't think they apply to the 1k without a little > > > >coding. > > > > > > > >73 Ed W2RF > > > > > > > >On 13 May 2008 at 22:14, Jerry Flanders wrote: > > > > > > > > > What radio are you using, Ed? > > > > > > > > > > Jerry W4UK > > > > > > > > > > At 07:29 PM 5/13/2008, Ed Russell wrote: > > > > > >I thought I was finished with PwrSDR QSK a couple of days > ago, but > > > > > >then I had a few more thoughts... > > > > > > > > > > > >There is a new version in the SVN branch w2rf\bin\release > > > > > > > > > > > >My favorite settings are DSP 4096/256 at 96Khz/512. What > are yours? > > > > > > > > > > > >I honestly think that these latest changes take QSK about > as far as > > > > > >it can go with the current architecture. Hopefully, someone > will > > > > > >prove me wrong :) > > > > > > > > > > > >73 Ed W2RF > > > > > > _______________________________________________ > FlexRadio Systems Mailing List > [email protected] > http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz > Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ > Knowledge Base: http://kb.flex-radio.com/ Homepage: > http://www.flex-radio.com/ > > > _______________________________________________ FlexRadio Systems Mailing List [email protected] http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kb.flex-radio.com/ Homepage: http://www.flex-radio.com/
