Thanks for the replies.
I've enabled the PA temp display (currently showing 22C right after
power-up but before transmitting), and will keep an eye on that.
Bob, I noticed that line in the K3S manual about the CW/SSB duty cycle.
Does "100% - 10 min, 100 W key-down" mean that if you key down without
stop in CW mode it can go 10 minutes at 100 watts? That seems like an
awful lot.
Where do the recommended TPO's for 6 meters, the 50% value for JT9, and
the 60C guideline for the PA temp come from?
Thanks again,
Frank K6FOD
On 4/4/20 6:22 AM, John Simmons wrote:
Fred Cady's book:
"There are four fans speeds that turn on at different temperatures."
"If the temperature reaches 84 degrees C the KPA3 will be bypassed
until the temperature falls to stop any damage as a last-ditch backup
measure to protect your expensive power transistors from the excess
heat."
-de John NI0K
Bob McGraw K4TAX wrote on 4/3/2020 6:39 PM:
Frank:
The duty cycle for the transmitter, as stated in the manual, is; CW
and SSB modes, 100% - 10 min, 100 W key-down at 25C ambient. Do
note that 6M has reduce power values of 85 watts {51 -52 MHz} or 70
watts {52 - 54 MHz}
The duty cycle for JT-9, 1 minute transmit, 1 minute receive would be
50%. I frequently run 100 watts on WSJT-X FT-8 with no issues.
Just pay attention to PA temperature. It should be 60 C or less.
Also this is with FANS in the automatic mode.
73
Bob, K4TAX
On 4/3/2020 4:18 PM, Frank O'Donnell wrote:
I've been using JT9 mode on 630m this winter with my K3S outputting
to an external class D amp.
Now I'm interested in trying some JT9 QSOs with some people
currently operating on 160m. For me this would mean outputting
directly from the K3S (with internal tuner) to the antenna.
Given the 1-minute cycle time for JT9, are there recommendations
(official from Elecraft, or otherwise) on maximum power to use in a
situation like this? And/or, is the answer dependent on the SWR I
can achieve with the antenna?
Thanks and 73,
Frank K6FOD
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