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 arch...@mail-archive.com
