Re: [Elecraft] Digital mode power handling for KAT3
I agree that the KAT3(a) can run 100 watts for quite a while. I have run 100 watts in RTTY contests with both of my K3S(s) without issue. I have never used FT8, I am sure that my RTTY transmissions are shorter than a 13 second FT8 transmission however the non-transmit time in-between RTTY transmissions can be very short when CQing at times. I have no personal experience with the KAT3's power capability, I am sure that it depends on what it is matching. I have all OWA Yagis so I have no need for a tuner. John KK9A David Gilbert AB7E wrote: I am reasonably certain that the KAT3 can handle 100 watts for a lengthy period to time (enough for normal FT8 purposes) if the SWR it is trying to match is low enough. But the original query didn't say how high an SWR he was trying to match. The KAT3 is certainly capable of matching some pretty high SWRs (well over 10:1), but the question is how long can it push 100 watts into an SWR that it could otherwise normally handle at lower SWR. Another factor is the phase of the impedance the KAT3 is trying to match. A high SWR could present either a capacitive load or an inductive load to the KAT3. In one case it could result in high currents within the KAT3 ... in another it could mean high internal voltages. So the real question is ... can the KAT3 survive for X amount of time when pushing 100 watts into a high SWR at most any phase? I can pretty much guarantee that nobody knows the answer to that question. I wouldn't be at all surprised if the KAT3 could handle 100 watts into a high SWR for periods of time that were comfortable for FT8 if the phase of the load impedance resulted in higher currents. I'm not so confident about that if the phase gave high voltages. Heating takes a bit of time to be destructive ... voltage breakdowns and arc overs happen very quickly. 73, Dave AB7E __ 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
Re: [Elecraft] Digital mode power handling for KAT3
__ 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
Re: [Elecraft] Digital mode power handling for KAT3
The answer is in the results of simple questions: Who, if any, has had their KAT3 fail and for what cause? What was actual (r,x,c) antenna load, that was being attempted? I suspect the failures are low, it's smart enough to quit trying if the match is too extreme. The same components (mostly) are used in the KAT500 (just larger sizes) which also has a low failure rate. Instead of guessing, answers of actual failures would provide data points. 73, Rick nk7i On 10/13/2023 11:56 AM, David Gilbert wrote: I am reasonably certain that the KAT3 can handle 100 watts for a lengthy period to time (enough for normal FT8 purposes) if the SWR it is trying to match is low enough. But the original query didn't say how high an SWR he was trying to match. The KAT3 is certainly capable of matching some pretty high SWRs (well over 10:1), but the question is how long can it push 100 watts into an SWR that it could otherwise normally handle at lower SWR. Another factor is the phase of the impedance the KAT3 is trying to match. A high SWR could present either a capacitive load or an inductive load to the KAT3. In one case it could result in high currents within the KAT3 ... in another it could mean high internal voltages. So the real question is ... can the KAT3 survive for X amount of time when pushing 100 watts into a high SWR at most any phase? I can pretty much guarantee that nobody knows the answer to that question. I wouldn't be at all surprised if the KAT3 could handle 100 watts into a high SWR for periods of time that were comfortable for FT8 if the phase of the load impedance resulted in higher currents. I'm not so confident about that if the phase gave high voltages. Heating takes a bit of time to be destructive ... voltage breakdowns and arc overs happen very quickly. 73, Dave AB7E On 10/13/2023 8:03 AM, Bill Frantz wrote: I have frequently used my K3 at 100 watts with FT8 and RTTY. I haven’t had anything which would indicate that components are getting overstressed (e.g. bad smells). Now, I don’t think I have given a full 100 watts when something isn’t connected in the antenna system, although the KAT3 does “match” an open antenna line. Since in that situation, it clicks for a long time before coming to a “match”, I tend to notice that there is a problem before applying full power. 73 Bill AE6JV On Oct 12, 2023, at 23:42, David Gilbert wrote: I thought I was clear, but apparently not. It is 100% duty cycle for 13 seconds, and zero for 2 + 15 seconds. "Duty cycle" is all a function of what period of time you choose to integrate over. Lots of components if heavily over stressed can go south in 13 seconds. Whether that is the case with the KAT3 is unspecified as far as I can tell. __ 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 rick.n...@gmail.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
Re: [Elecraft] Digital mode power handling for KAT3
I am reasonably certain that the KAT3 can handle 100 watts for a lengthy period to time (enough for normal FT8 purposes) if the SWR it is trying to match is low enough. But the original query didn't say how high an SWR he was trying to match. The KAT3 is certainly capable of matching some pretty high SWRs (well over 10:1), but the question is how long can it push 100 watts into an SWR that it could otherwise normally handle at lower SWR. Another factor is the phase of the impedance the KAT3 is trying to match. A high SWR could present either a capacitive load or an inductive load to the KAT3. In one case it could result in high currents within the KAT3 ... in another it could mean high internal voltages. So the real question is ... can the KAT3 survive for X amount of time when pushing 100 watts into a high SWR at most any phase? I can pretty much guarantee that nobody knows the answer to that question. I wouldn't be at all surprised if the KAT3 could handle 100 watts into a high SWR for periods of time that were comfortable for FT8 if the phase of the load impedance resulted in higher currents. I'm not so confident about that if the phase gave high voltages. Heating takes a bit of time to be destructive ... voltage breakdowns and arc overs happen very quickly. 73, Dave AB7E On 10/13/2023 8:03 AM, Bill Frantz wrote: I have frequently used my K3 at 100 watts with FT8 and RTTY. I haven’t had anything which would indicate that components are getting overstressed (e.g. bad smells). Now, I don’t think I have given a full 100 watts when something isn’t connected in the antenna system, although the KAT3 does “match” an open antenna line. Since in that situation, it clicks for a long time before coming to a “match”, I tend to notice that there is a problem before applying full power. 73 Bill AE6JV On Oct 12, 2023, at 23:42, David Gilbert wrote: I thought I was clear, but apparently not. It is 100% duty cycle for 13 seconds, and zero for 2 + 15 seconds. "Duty cycle" is all a function of what period of time you choose to integrate over. Lots of components if heavily over stressed can go south in 13 seconds. Whether that is the case with the KAT3 is unspecified as far as I can tell. __ 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
Re: [Elecraft] Digital mode power handling for KAT3
__ 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
[Elecraft] FS: [K3] LPA and two KSYN3 boards
"W3DVX Rescues Legacy Elecrafts" Hello, Selling several extra K3 boards: the 10W Low-Power Amp (LPA) and two KSYN3 boards. See photos and info at https://wilcoxengineering.com/sales Any questions, feel free to call or text 1300-2000 Eastern. Cheers, Alan Alan D. Wilcox, W3DVX (K3S-10457, SKCC 22955) 570-916-9590 (cell, text) https://WilcoxEngineering.com http://www.eham.net/reviews/detail/6768 ... Elecraft Client Comments http://amazon.com/author/alandwilcox Williamsport, PA 17701 __ 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
Re: [Elecraft] Digital mode power handling for KAT3
I have frequently used my K3 at 100 watts with FT8 and RTTY. I haven’t had anything which would indicate that components are getting overstressed (e.g. bad smells). Now, I don’t think I have given a full 100 watts when something isn’t connected in the antenna system, although the KAT3 does “match” an open antenna line. Since in that situation, it clicks for a long time before coming to a “match”, I tend to notice that there is a problem before applying full power. 73 Bill AE6JV > On Oct 12, 2023, at 23:42, David Gilbert wrote: > > I thought I was clear, but apparently not. It is 100% duty cycle for 13 > seconds, and zero for 2 + 15 seconds. "Duty cycle" is all a function of what > period of time you choose to integrate over. Lots of components if heavily > over stressed can go south in 13 seconds. Whether that is the case with the > KAT3 is unspecified as far as I can tell. __ 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
