Yes did read the manual but didn’t address the temperature matter much. On Mon, May 4, 2020 at 11:13 Jack Brindle via Elecraft < elecraft@mailman.qth.net> wrote:
> From the KPA500 manual, Rev E1, page 41 Specifications: > Duty Cycle at 500 Watts 10 minutes key down / 5 minutes standby > > Sometimes it is very worth while to read the manual. It gives me something > to do when being stuck at home for so long gets me down. > > 73! > Jack, W6FB > > > On May 4, 2020, at 6:39 AM, Dave Cole <d...@nk7z.net> wrote: > > > > Hi Rick, > > > > This brings up a point I have been unsure about for years... Duty > Cycle... What constitutes 100%? Over how long a time frame? > > > > If I run JT65, (one minute on one minute off), and I use a timeframe of > say 5 minutes, I buy it is 50% duty cycle. > > > > But if I use a timeframe of one minute it is 100% Duty Cycle... > > > > So when stating duty cycle it is important to spec the timeframe, as you > did... Is there an actual timeframe stated someplace as a standard? > > > > I do like the way you stated it by the way... With time to 'catch the > breath'... > > > > 73, and thanks, > > Dave (NK7Z) > > https://www.nk7z.net > > ARRL Volunteer Examiner > > ARRL Technical Specialist > > ARRL Asst. Director, NW Division, Technical Resources > > > > On 5/3/20 8:53 PM, Rick Bates, NK7I wrote: > >> I didn't add the obvious, FT8 in that manner is a 50% duty cycle but > with enough time to 'catch the breath'. > >> I remember back when it first came out, Wayne suggested to 'run it with > all the LEDs lit' or something along that line but... it's capable of MUCH > more than 500 watts and wisely better limited by firmware upgrades (in the > early days I watched it put out almost 700, at which point I was far more > cautious). It's nice to know there is a certain amount of 'overhead'. > >> Rick NK7I > >> On 5/3/2020 8:23 PM, Dave Cole wrote: > >>> Hi Rick, > >>> That is how mine behaves as well, almost exactly like that... However, > I will be running SSTV, and that is hard on the amp... I need to do a bit > more testing prior to that. > >>> > >>> As someone else said upthread, half power is really tough on the amp... > >>> > >>> 73, and thanks, > >>> Dave (NK7Z) > >>> https://www.nk7z.net > >>> ARRL Volunteer Examiner > >>> ARRL Technical Specialist > >>> ARRL Asst. Director, NW Division, Technical Resources > >>> > >>> On 5/3/20 7:52 PM, Rick Bates, NK7I wrote: > >>>> I spent 15 minutes active on 20M FT8 this afternoon (some lurking). > >>>> > >>>> At 530 watts output (on the display and utility) into a 1.13:1 > antenna load (SteppIR) for a ten minute calling period (Mongolia then > Oman), the temp rose to 66C; a few moments of elevated fan quickly brought > that down to the low 60's between transmissions. > >>>> > >>>> Ambient room temp 77F. (Both calls succeeded.) > >>>> > >>>> Rick NK7I > >>>> North Idaho > >>>> > >>>> On 5/3/2020 7:42 PM, Andy Durbin wrote: > >>>>> "It is interesting to hear how others experience their KPA500s over > various conditions." > >>>>> > >>>>> I have over a years's worth of KPA500 data recorded but it takes > some effort to run it through the Excel templates to make pretty plots. > >>>>> > >>>>> My KPA500 temperatures are strongly influenced by ambient > temperature. Shack temperature is often over 30 deg C in the summer months > and it's not at all unusual for my fan to run at level 3 in FT8 QSO. I > think I have only reached fan speed 5 twice and that was while running > temperature tests not while operating. I terminated those tests at fan > speed 5 and didn't wish to push it any higher. > >>>>> > >>>>> So many people seem to think reducing the output power will keep the > temperature down. It does not. Half power is about the worst heat > dissipation condition for the KPA500. > >>>>> > >>>>> 73, > >>>>> Andy, k3wyc > >>>>> ______________________________________________________________ > >>>>> 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 d...@nk7z.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 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 d...@nk7z.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 jackbrin...@me.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 w3tb....@gmail.com > -- 73 de Ted Edwards, W3TB and GØPWW and thinking about operating CW: "Do today what others won't, so you can do tomorrow what others can't." ______________________________________________________________ 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
