Upper limits of KPA500?
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Thanks Jack!
I guess part 2 to Jack's comments are... If it gets too hot, it starts to dial back the output power. (I would have to read the manual again to see if that is in there). Mike va3mw On Mon, May 4, 2020 at 12:12 PM Jack Brindle via Elecraft < [hidden email]> 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 <[hidden email]> 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:[hidden email] > >>>>> > >>>>> This list hosted by: http://www.qsl.net > >>>>> Please help support this email list: http://www.qsl.net/donate.html > >>>>> Message delivered to [hidden email] > >>>> ______________________________________________________________ > >>>> Elecraft mailing list > >>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft > >>>> Help: http://mailman.qth.net/mmfaq.htm > >>>> Post: mailto:[hidden email] > >>>> > >>>> This list hosted by: http://www.qsl.net > >>>> Please help support this email list: http://www.qsl.net/donate.html > >>>> Message delivered to [hidden email] > >>> ______________________________________________________________ > >>> Elecraft mailing list > >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft > >>> Help: http://mailman.qth.net/mmfaq.htm > >>> Post: mailto:[hidden email] > >>> > >>> This list hosted by: http://www.qsl.net > >>> Please help support this email list: http://www.qsl.net/donate.html > >>> Message delivered to [hidden email] > >> ______________________________________________________________ > >> Elecraft mailing list > >> Home: http://mailman.qth.net/mailman/listinfo/elecraft > >> Help: http://mailman.qth.net/mmfaq.htm > >> Post: mailto:[hidden email] > >> This list hosted by: http://www.qsl.net > >> Please help support this email list: http://www.qsl.net/donate.html > >> Message delivered to [hidden email] > > ______________________________________________________________ > > Elecraft mailing list > > Home: http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/mmfaq.htm > > Post: mailto:[hidden email] > > > > This list hosted by: http://www.qsl.net > > Please help support this email list: http://www.qsl.net/donate.html > > Message delivered to [hidden email] > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by John Simmons
Hi John,
Pretty much every answer to the Duty Cycle question involved time, hence why I asked about RTTY, that forced the issue of time to come into the definition. Based on the manual definition, 10 minutes out of every 15 can be in transmit. That seems to constitute 100% duty cycle for the KPA500. So I now have my question answered. 73, and thanks, Dave (NK7Z) https://www.nk7z.net ARRL Volunteer Examiner ARRL Technical Specialist ARRL Asst. Director, NW Division, Technical Resources On 5/4/20 6:53 AM, John Simmons wrote: > Nowadays manufacturers use 'ICAS'. One even specs their amp for '100% > duty cycle ICAS'. ICAS=Intermittent Continuous Amateur Service'. > Gobbledegook! > > 100% duty cycle is what Alpha used to say.... brick on the key forever. > FT8, JT65 are 50% duty cycle modes. SSB is about 33% during transmit, CW > is 50% during transmit. Duty cycle has no time limit. > > -de John NI0K > > Dave Cole wrote on 5/4/2020 8:39 AM: >> 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:[hidden email] >>>>>> >>>>>> This list hosted by: http://www.qsl.net >>>>>> Please help support this email list: http://www.qsl.net/donate.html >>>>>> Message delivered to [hidden email] >>>>> ______________________________________________________________ >>>>> Elecraft mailing list >>>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>>> Help: http://mailman.qth.net/mmfaq.htm >>>>> Post: mailto:[hidden email] >>>>> >>>>> This list hosted by: http://www.qsl.net >>>>> Please help support this email list: http://www.qsl.net/donate.html >>>>> Message delivered to [hidden email] >>>> ______________________________________________________________ >>>> Elecraft mailing list >>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>> Help: http://mailman.qth.net/mmfaq.htm >>>> Post: mailto:[hidden email] >>>> >>>> This list hosted by: http://www.qsl.net >>>> Please help support this email list: http://www.qsl.net/donate.html >>>> Message delivered to [hidden email] >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[hidden email] >>> >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> Message delivered to [hidden email] >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to [hidden email] > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Elecraft mailing list
Thank you Jack... I had not seen that. That answers the question.
73, and thanks, Dave (NK7Z) https://www.nk7z.net ARRL Volunteer Examiner ARRL Technical Specialist ARRL Asst. Director, NW Division, Technical Resources On 5/4/20 9:11 AM, Jack Brindle wrote: > From the KPA500 manual, Rev E1, page 41 Specifications: > > Duty Cycle at 500 Watts10 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 <[hidden email] >> <mailto:[hidden email]>> 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:[hidden email] >>>>>> >>>>>> This list hosted by: http://www.qsl.net >>>>>> Please help support this email list: http://www.qsl.net/donate.html >>>>>> Message delivered to [hidden email] >>>>> ______________________________________________________________ >>>>> Elecraft mailing list >>>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>>> Help: http://mailman.qth.net/mmfaq.htm >>>>> Post: mailto:[hidden email] >>>>> >>>>> This list hosted by: http://www.qsl.net >>>>> Please help support this email list: http://www.qsl.net/donate.html >>>>> Message delivered to [hidden email] >>>> ______________________________________________________________ >>>> Elecraft mailing list >>>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>>> Help: http://mailman.qth.net/mmfaq.htm >>>> Post: mailto:[hidden email] >>>> >>>> This list hosted by: http://www.qsl.net >>>> Please help support this email list: http://www.qsl.net/donate.html >>>> Message delivered to [hidden email] >>> ______________________________________________________________ >>> Elecraft mailing list >>> Home: http://mailman.qth.net/mailman/listinfo/elecraft >>> Help: http://mailman.qth.net/mmfaq.htm >>> Post: mailto:[hidden email] >>> This list hosted by: http://www.qsl.net >>> Please help support this email list: http://www.qsl.net/donate.html >>> Message delivered to [hidden email] >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to [hidden email] > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by John Simmons
On 5/4/2020 6:53 AM, John Simmons wrote:
> Nowadays manufacturers use 'ICAS'. One even specs their amp for '100% > duty cycle ICAS'. ICAS=Intermittent Continuous Amateur Service'. > Gobbledegook! Not really. ICAS and CCS have been used by power tube mfrs longer than I have been reading their data sheets in the '50s. 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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1850, or 1950? Sorry Jim, I had too... :)
73, and thanks, Dave (NK7Z) https://www.nk7z.net ARRL Volunteer Examiner ARRL Technical Specialist ARRL Asst. Director, NW Division, Technical Resources On 5/4/20 11:24 AM, Jim Brown wrote: > Not really. ICAS and CCS have been used by power tube mfrs longer than I > have been reading their data sheets in the '50s. > > 73, Jim K9YC > ______________________________________________________________ ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by NK7Z
That seems excessive (shows good engineering).
FM seems to be the hardest mode on amps. If you are long-winded probably exceed 3-minutes which is common Time-out-timer limit on commercial FM gear (and several ham rigs, too). I have a fan switch on my 150w 2m amp and too often forget to switch it on when operating FM. My 222 FM 30w radio has built-in TOT which shuts off Tx at 3-minutes of transmit. On my QRO sspa's I try not to do any key-down tests over a minute in length (and they are designed for JT65 service). Having overtemp protection and SWR protection is good insurance for protecting those expensive components. All my amps have that. Maybe someday I will own a KPA500 (do very little HF and have a 1000w 6m sspa). 73, Ed - KL7UW I once blew up a 500w dummy load by excessive transmit time running 1200w. Had that old Sierra MW for about 30-years. Now have a surplus 500w Bird dummy. Date: Mon, 4 May 2020 09:11:56 -0700 From: Jack Brindle <[hidden email]> To: Dave Cole <[hidden email]> Cc: [hidden email] Subject: Re: [Elecraft] Upper limits of KPA500? Message-ID: <[hidden email]> Content-Type: text/plain; charset=us-ascii 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 73, Ed - KL7UW http://www.kl7uw.com Dubus-NA Business mail: [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: Upper limits of KPA500?
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In reply to this post by Jim Brown-10
That would be "Intermittent Commercial and Amateur Service".
73 Bob, K4TAX On 5/4/2020 1:24 PM, Jim Brown wrote: > On 5/4/2020 6:53 AM, John Simmons wrote: >> Nowadays manufacturers use 'ICAS'. One even specs their amp for '100% >> duty cycle ICAS'. ICAS=Intermittent Continuous Amateur Service'. >> Gobbledegook! > > ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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Bob,
My bad... thanks for the correction. However, the key word is 'intermittent'. So, what in the world does 'continuous intermittent' mean? -de John NI0K Bob McGraw K4TAX wrote on 5/4/2020 3:06 PM: > That would be "Intermittent Commercial and Amateur Service". > > 73 > > Bob, K4TAX > > > > On 5/4/2020 1:24 PM, Jim Brown wrote: >> On 5/4/2020 6:53 AM, John Simmons wrote: >>> Nowadays manufacturers use 'ICAS'. One even specs their amp for >>> '100% duty cycle ICAS'. ICAS=Intermittent Continuous Amateur >>> Service'. Gobbledegook! >> >> > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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I imagine like a repeater. Always ON w/light load and intermittent heavy load.
Sent from my iPhone ...nr4c. bill > On May 4, 2020, at 7:03 PM, John Simmons <[hidden email]> wrote: > > Bob, > > My bad... thanks for the correction. However, the key word is 'intermittent'. So, what in the world does 'continuous intermittent' mean? > > -de John NI0K > > Bob McGraw K4TAX wrote on 5/4/2020 3:06 PM: >> That would be "Intermittent Commercial and Amateur Service". >> >> 73 >> >> Bob, K4TAX >> >> >> >>> On 5/4/2020 1:24 PM, Jim Brown wrote: >>> On 5/4/2020 6:53 AM, John Simmons wrote: >>>> Nowadays manufacturers use 'ICAS'. One even specs their amp for '100% duty cycle ICAS'. ICAS=Intermittent Continuous Amateur Service'. Gobbledegook! >>> >>> >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[hidden email] >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to [hidden email] > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Elecraft mailing list
This has been very educational. I have, unfortunately, faulted both my
veteran KPA500 and KPA1500 more times than I can count. I've been so paranoid about keeping them otherwise healthy, that I manually manipulate the fan speed using the utilities--increasing the KPA500 fan speed when it gets into the 60Cs, and the KPA1500 when it gets into the 70Cs. The downside is I sometimes forget to reduce the fans when the chase is over, and the amps quickly cool to room temperature, only to heat up again when the next chase is underfoot. Is this rapid cooling and heating even worse for the life of the devices, and then again what about turning off the amps when going QRT? Should they be cooled to room temp first, or just until the fans stop running in NOR mode? The question isn't is one paranoid, but is one paranoid enough? 73 Eric WD6DBM On Mon, May 4, 2020, 9:12 AM Jack Brindle via Elecraft < [hidden email]> 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 > > > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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Remember... Just because you think they are out to get you, does not
mean they are not out to get you... 73, and thanks, Dave (NK7Z) https://www.nk7z.net ARRL Volunteer Examiner ARRL Technical Specialist ARRL Asst. Director, NW Division, Technical Resources On 5/5/20 2:33 PM, Eric Norris wrote: > This has been very educational. I have, unfortunately, faulted both my > veteran KPA500 and KPA1500 more times than I can count. I've been so > paranoid about keeping them otherwise healthy, that I manually > manipulate the fan speed using the utilities--increasing the KPA500 fan > speed when it gets into the 60Cs, and the KPA1500 when it gets into the > 70Cs. > > The downside is I sometimes forget to reduce the fans when the chase is > over, and the amps quickly cool to room temperature, only to heat up > again when the next chase is underfoot. Is this rapid cooling and > heating even worse for the life of the devices, and then again what > about turning off the amps when going QRT? Should they be cooled to > room temp first, or just until the fans stop running in NOR mode? > > The question isn't is one paranoid, but is one paranoid enough? > > 73 Eric WD6DBM > > On Mon, May 4, 2020, 9:12 AM Jack Brindle via Elecraft > <[hidden email] <mailto:[hidden email]>> 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 > > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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Actually that would be good to know... I let the
fans take the temp down to room temp before shutting the 1500 off... Frank (W2YK) At 07:35 PM 5/5/2020, Dave Cole wrote: >Remember... Just because you think they are out >to get you, does not mean they are not out to >get you... 73, and thanks, Dave (NK7Z) >https://www.nk7z.net ARRL Volunteer Examiner >ARRL Technical Specialist ARRL Asst. Director, >NW Division, Technical Resources On 5/5/20 2:33 >PM, Eric Norris wrote: > This has been very >educational. I have, unfortunately, faulted >both my > veteran KPA500 and KPA1500 more times >than I can count. I've been so > paranoid >about keeping them otherwise healthy, that I >manually > manipulate the fan speed using the >utilities--increasing the KPA500 fan > speed >when it gets into the 60Cs, and the KPA1500 when >it gets into the > 70Cs. > > The downside is I >sometimes forget to reduce the fans when the >chase is > over, and the amps quickly cool to >room temperature, only to heat up > again when >the next chase is underfoot. Is this rapid >cooling and > heating even worse for the life of >the devices, and then again what > about turning >off the amps when going QRT? Should they be >cooled to > room temp first, or just until the >fans stop running in NOR mode? > > The question >isn't is one paranoid, but is one paranoid >enough? > > 73 Eric WD6DBM > > On Mon, May 4, >2020, 9:12 AM Jack Brindle via Elecraft > ><[hidden email] ><mailto:[hidden email]>> >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 > > >______________________________________________________________ >Elecraft mailing list Home: >http://mailman.qth.net/mailman/listinfo/elecraft >Help: http://mailman.qth.net/mmfaq.htm Post: >mailto:[hidden email] This list hosted >by: http://www.qsl.net Please help support this >email list: http://www.qsl.net/donate.html Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Eric Norris-2
Why not let the computer in the amp do its job? And besides, the fans run after the amp is turned OFF. This discharges the caps and starts the orderly “cool down” cycle.
You may be a brilliant engineer, but no need to re-engineer a system that works pretty well. Sent from my iPhone ...nr4c. bill > On May 5, 2020, at 5:35 PM, Eric Norris <[hidden email]> wrote: > > This has been very educational. I have, unfortunately, faulted both my > veteran KPA500 and KPA1500 more times than I can count. I've been so > paranoid about keeping them otherwise healthy, that I manually manipulate > the fan speed using the utilities--increasing the KPA500 fan speed when it > gets into the 60Cs, and the KPA1500 when it gets into the 70Cs. > > The downside is I sometimes forget to reduce the fans when the chase is > over, and the amps quickly cool to room temperature, only to heat up again > when the next chase is underfoot. Is this rapid cooling and heating even > worse for the life of the devices, and then again what about turning off > the amps when going QRT? Should they be cooled to room temp first, or just > until the fans stop running in NOR mode? > > The question isn't is one paranoid, but is one paranoid enough? > > 73 Eric WD6DBM > >> On Mon, May 4, 2020, 9:12 AM Jack Brindle via Elecraft < >> [hidden email]> 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 >> >> >> > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: Upper limits of KPA500?
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In reply to this post by NK7Z
Hi Dave,
I run around 100-150 watts out of my KPA500 using 5-7 watts from my K3 with the KPA500 hitting 70C using Olivia during nets. I assume could go to 250 but never needed that much power. Does not seem to be a problem with temps above 70c. Also run up to 500w PEP using SSB when needed. I did hear Wayne say run full power RTTY with no fear. 73, tom w7sua On 5/3/2020 1:26 PM, Dave Cole wrote: > Hello, > > I just got the new MMSSTV software, and will be running a bit of SSTV. > SSTV is 100% duty cycle. > > Initial testing here indicates no power level is safe... At 150 watts > the KPA500 reaches 70C pretty fast, in under two minutes, and 70C is my > upper limit for testing... At 500 watts it reaches 70C in about the > same time... > > Can I assume the amp is not the most efficient thing in the world at 200 > watts? > > If the KPA500 can't deal with 100% duty cycle, for two minutes, how does > the K3 deal with 100 watts for two minutes, at 100% duty cycle? > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
Re: Upper limits of KPA500?
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As long as one stays within the duty cycle times limits, no problem.
Do note that some antenna system which are lower impedance will require the amp to draw more current for a given amount of power. And it does vary from band to band. The attached EXCEL spreadsheet should be of interest regarding lower power operation. 73 Bob, K4TAX On 5/6/2020 1:03 PM, Tom Azlin W7SUA wrote: > Hi Dave, > > I run around 100-150 watts out of my KPA500 using 5-7 watts from my K3 > with the KPA500 hitting 70C using Olivia during nets. I assume could > go to 250 but never needed that much power. Does not seem to be a > problem with temps above 70c. Also run up to 500w PEP using SSB when > needed. > > I did hear Wayne say run full power RTTY with no fear. > > 73, tom w7sua > > > > > > On 5/3/2020 1:26 PM, Dave Cole wrote: >> Hello, >> >> I just got the new MMSSTV software, and will be running a bit of >> SSTV. SSTV is 100% duty cycle. >> >> Initial testing here indicates no power level is safe... At 150 >> watts the KPA500 reaches 70C pretty fast, in under two minutes, and >> 70C is my upper limit for testing... At 500 watts it reaches 70C in >> about the same time... >> >> Can I assume the amp is not the most efficient thing in the world at >> 200 watts? >> >> If the KPA500 can't deal with 100% duty cycle, for two minutes, how >> does the K3 deal with 100 watts for two minutes, at 100% duty cycle? >> > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by Tom Azlin W7SUA-2
I ragchew on CW and have my KPA500 fan set on level 2 as a default. I don't really keep an eye on the temp. When I hear fan level 3 kick in, that's my cue I've been too longed winded and time to turn it over :)
John K7FD > On May 6, 2020, at 11:03 AM, Tom Azlin W7SUA <[hidden email]> wrote: > > Hi Dave, > > I run around 100-150 watts out of my KPA500 using 5-7 watts from my K3 with the KPA500 hitting 70C using Olivia during nets. I assume could go to 250 but never needed that much power. Does not seem to be a problem with temps above 70c. Also run up to 500w PEP using SSB when needed. > > I did hear Wayne say run full power RTTY with no fear. > > 73, tom w7sua > > > > > >> On 5/3/2020 1:26 PM, Dave Cole wrote: >> Hello, >> I just got the new MMSSTV software, and will be running a bit of SSTV. SSTV is 100% duty cycle. >> Initial testing here indicates no power level is safe... At 150 watts the KPA500 reaches 70C pretty fast, in under two minutes, and 70C is my upper limit for testing... At 500 watts it reaches 70C in about the same time... >> Can I assume the amp is not the most efficient thing in the world at 200 watts? >> If the KPA500 can't deal with 100% duty cycle, for two minutes, how does the K3 deal with 100 watts for two minutes, at 100% duty cycle? > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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In reply to this post by NK7Z
NK7Z wrote
> > Initial testing here indicates no power level is safe... At 150 watts > the KPA500 reaches 70C pretty fast, in under two minutes, and 70C is my > upper limit for testing... At 500 watts it reaches 70C in about the > same time... > > Can I assume the amp is not the most efficient thing in the world at 200 > watts? Correct! Up to a certain limit, the output power increases with PA current quadratically. So the maximum dissipation may be below the max power, and decreasing power does not reduce dissipation much. Assume that at 600W KPA500 operates at 60% efficiency. 1000W total, 400W dissipation. Now reduced the power to 1/4 or 150W. The input current is reduced 50% to 500W. The dissipation is 350W, not much below 400W at full power. With KAP500, the dissipation at low power can actually get worse than predicted since the power supply is unregulated and has higher voltage at lower current. Reduction of dissipation at low power can be done at least 2 ways. One is reduction of voltage as done in SPE amps. The other one is changing the the transformation ratio of output amp, e.g., in KX3; hard to do at high power. One can have the action of a different transformation ratio with a manual tuner. Once my 20A power supply died but I had a 5A supply available. But the max power was only 5W before the power supply switched off. 1/4 curent = 1/16 power. By adjusting a manual tuner for max output I got 20W. But KPA may not let this trick go because of SWR. protection. Ignacy, NO9E -- Sent from: http://elecraft.365791.n2.nabble.com/ ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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Thank you for a very thorough, and cogent, explanation of that.
73, and thanks, Dave (NK7Z) https://www.nk7z.net ARRL Volunteer Examiner ARRL Technical Specialist ARRL Asst. Director, NW Division, Technical Resources On 5/7/20 7:12 AM, Ignacy wrote: > NK7Z wrote >> >> Initial testing here indicates no power level is safe... At 150 watts >> the KPA500 reaches 70C pretty fast, in under two minutes, and 70C is my >> upper limit for testing... At 500 watts it reaches 70C in about the >> same time... >> >> Can I assume the amp is not the most efficient thing in the world at 200 >> watts? > > Correct! > > Up to a certain limit, the output power increases with PA current > quadratically. So the maximum dissipation may be below the max power, and > decreasing power does not reduce dissipation much. > > Assume that at 600W KPA500 operates at 60% efficiency. 1000W total, 400W > dissipation. > Now reduced the power to 1/4 or 150W. The input current is reduced 50% to > 500W. The dissipation is 350W, not much below 400W at full power. With > KAP500, the dissipation at low power can actually get worse than predicted > since the power supply is unregulated and has higher voltage at lower > current. > > Reduction of dissipation at low power can be done at least 2 ways. One is > reduction of voltage as done in SPE amps. The other one is changing the the > transformation ratio of output amp, e.g., in KX3; hard to do at high power. > > One can have the action of a different transformation ratio with a manual > tuner. Once my 20A power supply died but I had a 5A supply available. But > the max power was only 5W before the power supply switched off. 1/4 curent = > 1/16 power. By adjusting a manual tuner for max output I got 20W. But KPA > may not let this trick go because of SWR. protection. > > Ignacy, NO9E > > > > > > -- > Sent from: http://elecraft.365791.n2.nabble.com/ > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:[hidden email] > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to [hidden email] > Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[hidden email] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [hidden email] |
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