Don, What you are saying translates into " Do not talk into the mike or touch keyer for 30 ms or more after you press PTT footswitch". I know that. But this method can hardly be called fool proof for contesting. In fact, even 8 ms delay woul not be needed.
73, Igor UA9CDC > Igor, > > I understand your situation, but the application of PTT does not produce > any RF - nothing will hot switch. > When you "hit the key" (or for SSB begin talking), then RF is produced. > If you arrange your switching to be accomplished by either the PTT or the > K3 KEYOUT, and leave the K3 in non-VOX state, there is no need to increase > TX DLY to any other than the 8 ms default value and therefore no > shortening of CW elements. > > 73, > Don W3FPR > > On 2/17/2012 6:52 AM, Igor Sokolov wrote: >> Don, >> I will try to explain. >> Forget about QSK all together. >> Apart from linear amp, there are other external relays like stack control >> relays, T/R relays when you want to use different antennas for TX/RX etc. >> PTT signal can either be controlled by the logger (CW, VOICE Keyer, DIGI >> modes) or by PTT footswitch. In both cases PTT signal goes into PTT IN of >> K3. >> About 6ms later you get sort of PTT OUT on the KEY OUT connector. This >> KEY >> OUT signal controls linear, T/R antenna relays, stack relays etc. Then >> 8ms >> later you get RF out of the K3. These 8ms is not enough for all the >> external >> relays to settle. >> PTT delay of 20 ms should be more or less OK (although I would not mind >> it >> to be extended to 30ms) but then CW generated by a logger gets choppy. >> I can overcome the problem of non adjustable TX delay of K3 by >> configuring >> my logger to start sending say 30 ms after PTT was asserted. I can even >> connect PTT footswitch to the computer, but that will only work for CW >> sending from the keyboard, computer voice keyer and digi signals >> generated >> by the computer. If I send from the K3 internal keyer or use k3 mike I am >> in >> danger to hot switch some of the external relays. >> Therefore instead of being able to extend TX delay inside K3 I will >> probably >> have to build some sort of circit which will take low level from KEY OUT >> and >> form some sort of positive or negative impulse of a required length (say >> 30 >> ms) to apply to INH input of K3. I was hoping to build it inside the >> DB-15 >> cabinet since KEY OUT and INH pins are available on the ACC connector. >> But >> there is no any 12 v or 5v pins available on that connector. So it makes >> life more complicated. >> If you can suggest different approach. which does not involve building >> external sequencer, I would really appreciate it. >> >> 73, Igor UA9CDC >> >> >>> I fail to understand why anyone who is using PTT switching would want to >>> set the TX DLY parameter to greater than the default of 8 ms. Use PTT >>> and >>> a footswitch if you are using a slow amp relay. >>> >>> If your amplifier uses a slow relay, then you really cannot use QSK, so >>> just use PTT and a footpedal instead - things will work out much better. >>> There are QSK mods available for amplifiers that use slow relays. Some >>> mods are relatively inexpensive (the owner does the work), while other >>> can >>> cost upwards of $400 (purchase a commercial version). >>> >>> 73, >>> Don W3FPR >>> >>> On 2/16/2012 11:05 PM, Igor Sokolov wrote: >>>>> But I am finishing my 300w HF amplifier kit and will be using a dc >>>>> open-frame relay for TR switching of RF. I guess I can time it using >>>>> my dual trace scope and set K3 TX DLY accordingly (amp will be keyed >>>>> with KEYOUT). I do not use CW very much on HF so QSK with 300w is >>>>> not necessary (or probably possible). >>>> Even if you use PTT CW and set TX delay for 20 ms you will get choppy >>>> CW >>>> >>>>> There is one thing I do not see being addressed in this >>>>> discussion. Maybe more important than clipping of CW characters is >>>>> avoiding QRO "Hot Switching" of RF. Calculate the RF voltage for >>>>> several thousand ohms impedance (open circuit) that will result if >>>>> the amp is pumping out "globs" of RF before being connected to a good >>>>> load. The relay contacts will definitely get burned big time. And >>>>> maybe your output devices will have a short live-span. >>>>> >>>>> >>>>> 73, Ed - KL7UW, WD2XSH/45 >>>> The entire topic stems from the fact that I wanted to avoid hot >>>> switching >>>> of >>>> the external relays (linear amp, stack switching etc). To acheave that >>>> I >>>> have tried to increase TX delay and got choppy CW. So without external >>>> sequencer there is a choise between the two - 'hot switching' or >>>> 'choppy >>>> cw'. >>>> >>>> 73. Igor UA9CDC >>>> >>>> >>>>> ====================================== >>>>> BP40IQ 500 KHz - 10-GHz www.kl7uw.com >>>>> EME: 50-1.1kw?, 144-1.4kw, 432-QRT, 1296-?, 3400-? >>>>> DUBUS Magazine USA Rep [email protected] >>>>> "Kits made by KL7UW" http://www.kl7uw.com/kits.htm >>>>> ====================================== >>>>> ______________________________________________________________ >>>>> Elecraft mailing list >>>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>>> Help: http://mailman.qth.net/mmfaq.htm >>>>> Post: mailto:[email protected] >>>>> >>>>> This list hosted by: http://www.qsl.net >>>>> Please help support this email list: http://www.qsl.net/donate.html >>>> ______________________________________________________________ >>>> Elecraft mailing list >>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>> Help: http://mailman.qth.net/mmfaq.htm >>>> Post: mailto:[email protected] >>>> >>>> This list hosted by: http://www.qsl.net >>>> Please help support this email list: http://www.qsl.net/donate.html >>>> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[email protected] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
