Hi Kevin, The K2 is only rated 100% duty cycle at 5 Watts and 50% duty cycle at 10 Watts. Even though it will put out 15 Watts it should only be run there on SSB and CW and then sparingly. It should not be run on digital modes above 10 Watts and really should not be run at more than 5 Watts on digital. I have a K2 for my QRP ops and never run it more than 7 or 8 Watts.
73, Mark, WB9CIF -----Original Message----- From: elecraft-boun...@mailman.qth.net <elecraft-boun...@mailman.qth.net> On Behalf Of Kevin Robertson via Elecraft Sent: Saturday, June 4, 2022 13:53 To: Rick NK7I <rick.n...@gmail.com> Cc: elecraft@mailman.qth.net Subject: Re: [Elecraft] KPA1500 reduces power as it gets warmer? FT8 is a weak signal mode, designed for low power. Given its high duty cycle, you are asking for trouble if you operate your power amplifier in FT8 mode using your KPA1500 at anywhere near high power. I burned out my final on my K2 at 15 watts on FT8. 73, Kevin Robertson KD2WCY > On Jun 4, 2022, at 12:42 AM, Rick NK7I <rick.n...@gmail.com> wrote: > > Yes, the KPA1500 will drop 10% of the output, as it warms up. 1500 drops to > 1350, so you have to compensate with the drive. > > I'm told this is typical of all solid state finals (my KPA500 did likewise). > > If you're running the station remotely; bump up the fan speed to slow the > drop (or wear cans). > > 73, > Rick NK7I > >> On 6/3/2022 9:22 PM, David F. Reed wrote: >> I note my KPA1500 drops power at its temperature rises... >> >> Using FT8, so a relatively high duty cycle. >> >> Say I start at a heat sink temperature of 27 C, and 1,000 watts out; by the >> time the temperature is at 65 C, the power has dropped to 893 watts out. >> >> I have a couple of questions about this (not a complaint by the way): >> >> 1. Does anyone else experience this? >> 2. Is it normal? >> > ______________________________________________________________ > Elecraft mailing list > Home: > https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Fmailm > an.qth.net%2Fmailman%2Flistinfo%2Felecraft&data=05%7C01%7C%7C4eb1e > 51f31274b9cd4c708da4631b02e%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0 > %7C637899476465505240%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQ > IjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=5 > D58W1nWCJAOBAGqUtr3qX3FiiRcGO2ycAJ3hOTE6Do%3D&reserved=0 > Help: > https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Fmailm > an.qth.net%2Fmmfaq.htm&data=05%7C01%7C%7C4eb1e51f31274b9cd4c708da4 > 631b02e%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C63789947646550524 > 0%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6 > Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=pK0q7iMt4%2BSWF2LvMi9 > v8k2bn85SFQQ7Fo6AsFaUgNg%3D&reserved=0 > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: > https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.q > sl.net%2F&data=05%7C01%7C%7C4eb1e51f31274b9cd4c708da4631b02e%7C84d > f9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637899476465505240%7CUnknown%7 > CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXV > CI6Mn0%3D%7C3000%7C%7C%7C&sdata=MezqyqjC7F5Ebng8bsuDhQavi50EInEswD > U4Ua8LT%2Fs%3D&reserved=0 Please help support this email list: > https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.q > sl.net%2Fdonate.html&data=05%7C01%7C%7C4eb1e51f31274b9cd4c708da463 > 1b02e%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637899476465505240% > 7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik > 1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=UupDEzxtRI9irXki4nflrNv > 90uuONuN6XeQg%2FZGRpWs%3D&reserved=0 > Message delivered to kevin_robert...@me.com ______________________________________________________________ Elecraft mailing list Home: https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Fmailman.qth.net%2Fmailman%2Flistinfo%2Felecraft&data=05%7C01%7C%7C4eb1e51f31274b9cd4c708da4631b02e%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637899476465505240%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=5D58W1nWCJAOBAGqUtr3qX3FiiRcGO2ycAJ3hOTE6Do%3D&reserved=0 Help: https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Fmailman.qth.net%2Fmmfaq.htm&data=05%7C01%7C%7C4eb1e51f31274b9cd4c708da4631b02e%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637899476465505240%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=pK0q7iMt4%2BSWF2LvMi9v8k2bn85SFQQ7Fo6AsFaUgNg%3D&reserved=0 Post: mailto:Elecraft@mailman.qth.net This list hosted by: https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.qsl.net%2F&data=05%7C01%7C%7C4eb1e51f31274b9cd4c708da4631b02e%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637899476465505240%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=MezqyqjC7F5Ebng8bsuDhQavi50EInEswDU4Ua8LT%2Fs%3D&reserved=0 Please help support this email list: https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.qsl.net%2Fdonate.html&data=05%7C01%7C%7C4eb1e51f31274b9cd4c708da4631b02e%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637899476465505240%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=UupDEzxtRI9irXki4nflrNv90uuONuN6XeQg%2FZGRpWs%3D&reserved=0 Message delivered to markmus...@outlook.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
