Re: [Elecraft] PBSK31
Hello Phil, My K2's serial number is in the 5000s so it has the temperature stability circuit built in. I have only just recently started using it on JT9 after some time on JT65. I don't start transmitting until it has warmed up after 5 minutes or so. I first used it outdoors at my remote site (see VK3TUN on qrz.com) and had to shield it from the wind. Now that the shed is up, that is no longer an issue. I don't know if it helps that much with dissipating the heat, but I always have the bail extended. 73 de David VK5DG / VK3TUN On 25/04/2016 7:53 AM, Phil Wheeler wrote: David, Do you do anything special to ensure frequency stability in those modes with your K2? Phil W7OX On 4/24/16 3:02 PM, David Giles wrote: I've made hundreds of contacts using JT65 and JT9 with my K2 at 5W. Most of these portable on a 12v battery with solar charging. With a 48 second transmit period, it's probably more of a stress test than BPSK31. 73 de David VK5DG / VK3TUN On 24/04/2016 2:07 PM, Bruce Rattray wrote: What is the safe level to operate the K2 at for the PBSK31 mode? I'm thinking 2 or 3 watts. tnx 73 Bruce ve5rc __ 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 vk...@internode.on.net __ 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] PBSK31
Phil and all, Yes, those mods can do a lot for temperature stability of the K2. Adjust the Thermistor board RA value if necessary to achieve the best stability. The KX3 can achieve good temperature stability if the Extended Temperature Compensation procedure is completed - I would not attempt any of the JT data modes without doing that first. 73, Don W3FPR On 4/24/2016 7:28 PM, Phil Wheeler wrote: I've done all those mods to #380, Don. I didn't realize they were that effective! And after reading of thermal stability issues some have had in JT65 (e.g., using a KX3) I assumed the K2/10 would have even larger issues in those modes, given the age of the design. Your message is good news indeed! 73, Phil W7OX __ 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] PBSK31
I've done all those mods to #380, Don. I didn't realize they were that effective! And after reading of thermal stability issues some have had in JT65 (e.g., using a KX3) I assumed the K2/10 would have even larger issues in those modes, given the age of the design. Your message is good news indeed! 73, Phil W7OX On 4/24/16 3:52 PM, Don Wilhelm wrote: Phil, I cannot say if David did anything special for frequency stability, but any K2 above SN 3000 had the BFO stability mod and the PLL Temperature compensation mod installed which can achieve the necessary stability. K2s below SN 3000 can be upgraded with those upgrade kits. The stock PLL Temperature Stability Mod has resistor RA as a 33k resistor. That resistor value can be modified to achieve closer temperature stability for any particular K2. The K2 manual does not contain information about how to vary and check the compensation, but that information is contained in the instructions for the PLL Temperature Stability Mod - download from Elecraft. The temperature change in the K2/10 is not likely to be very much even for long periods of transmit because the PA transistors and heatsink are not close to the VFO/PLL and BFO areas and there is a lot of 'air space' inside the enclosure. With the KPA100 added, that air space is much more confined and the heat from the KPA100 PA transistors will have an influence. In other words, while the stock K2/10 may be sufficiently stable, the K2/100 may need some 'tweaking' of the RA resistor value for equivalent stability. 73, Don W3FPR On 4/24/2016 6:23 PM, Phil Wheeler wrote: David, Do you do anything special to ensure frequency stability in those modes with your K2? Phil W7OX On 4/24/16 3:02 PM, David Giles wrote: I've made hundreds of contacts using JT65 and JT9 with my K2 at 5W. Most of these portable on a 12v battery with solar charging. With a 48 second transmit period, it's probably more of a stress test than BPSK31. 73 de David VK5DG / VK3TUN __ 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] PBSK31
Phil, I cannot say if David did anything special for frequency stability, but any K2 above SN 3000 had the BFO stability mod and the PLL Temperature compensation mod installed which can achieve the necessary stability. K2s below SN 3000 can be upgraded with those upgrade kits. The stock PLL Temperature Stability Mod has resistor RA as a 33k resistor. That resistor value can be modified to achieve closer temperature stability for any particular K2. The K2 manual does not contain information about how to vary and check the compensation, but that information is contained in the instructions for the PLL Temperature Stability Mod - download from Elecraft. The temperature change in the K2/10 is not likely to be very much even for long periods of transmit because the PA transistors and heatsink are not close to the VFO/PLL and BFO areas and there is a lot of 'air space' inside the enclosure. With the KPA100 added, that air space is much more confined and the heat from the KPA100 PA transistors will have an influence. In other words, while the stock K2/10 may be sufficiently stable, the K2/100 may need some 'tweaking' of the RA resistor value for equivalent stability. 73, Don W3FPR On 4/24/2016 6:23 PM, Phil Wheeler wrote: David, Do you do anything special to ensure frequency stability in those modes with your K2? Phil W7OX On 4/24/16 3:02 PM, David Giles wrote: I've made hundreds of contacts using JT65 and JT9 with my K2 at 5W. Most of these portable on a 12v battery with solar charging. With a 48 second transmit period, it's probably more of a stress test than BPSK31. 73 de David VK5DG / VK3TUN __ 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] PBSK31
David, Do you do anything special to ensure frequency stability in those modes with your K2? Phil W7OX On 4/24/16 3:02 PM, David Giles wrote: I've made hundreds of contacts using JT65 and JT9 with my K2 at 5W. Most of these portable on a 12v battery with solar charging. With a 48 second transmit period, it's probably more of a stress test than BPSK31. 73 de David VK5DG / VK3TUN On 24/04/2016 2:07 PM, Bruce Rattray wrote: What is the safe level to operate the K2 at for the PBSK31 mode? I'm thinking 2 or 3 watts. tnx 73 Bruce ve5rc __ 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] PBSK31
I've made hundreds of contacts using JT65 and JT9 with my K2 at 5W. Most of these portable on a 12v battery with solar charging. With a 48 second transmit period, it's probably more of a stress test than BPSK31. 73 de David VK5DG / VK3TUN On 24/04/2016 2:07 PM, Bruce Rattray wrote: What is the safe level to operate the K2 at for the PBSK31 mode? I'm thinking 2 or 3 watts. tnx 73 Bruce ve5rc __ 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 vk...@internode.on.net __ 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] PBSK31
Wouldn't want to go much higher than 5W though -- you want to maintain linearity, and PSK31 has a peak-to-average-power-ratio of 3dB. 73, Matt VK2RQ Envoyé d’Outlook Mobile On Sun, Apr 24, 2016 at 6:18 AM -0700, "lstavenhagen" wrote: I agree with Don, the K2 should be brick-on-key at 5 watts at least. On m 12V batteries, mine are almost that way at full power, the heat sink at the bottom definitely gets warm but seems to go forever without getting hot. On a regulated PS, though, that doesn't drop into the 11v range like my batts, that may not be true 73, LS W5QD -- View this message in context: http://elecraft.365791.n2.nabble.com/PBSK31-tp7616597p7616600.html Sent from the Elecraft mailing list archive at Nabble.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 matt.vk...@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] PBSK31
I agree with Don, the K2 should be brick-on-key at 5 watts at least. On m 12V batteries, mine are almost that way at full power, the heat sink at the bottom definitely gets warm but seems to go forever without getting hot. On a regulated PS, though, that doesn't drop into the 11v range like my batts, that may not be true 73, LS W5QD -- View this message in context: http://elecraft.365791.n2.nabble.com/PBSK31-tp7616597p7616600.html Sent from the Elecraft mailing list archive at Nabble.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] PBSK31
Bruce, I always operated mine at 5 watts. The K2/10 has a large heatsink area. You may want to try even higher than 5 watts - if you want to check to make sure it is OK, feel the bottom rear panel of the K2 enclosure. It will be warm, But you should still be able to hold your fingers on it. If it is too hot to touch continually, it is too hot. 73, Don W3FPR On 4/24/2016 12:37 AM, Bruce Rattray wrote: What is the safe level to operate the K2 at for the PBSK31 mode? I'm thinking 2 or 3 watts. tnx 73 Bruce ve5rc __ 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] PBSK31
What is the safe level to operate the K2 at for the PBSK31 mode? I'm thinking 2 or 3 watts. tnx 73 Bruce ve5rc __ 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