[Elecraft] Max power for JT9 with K3S 100?

Bob McGraw K4TAX rmcgraw at blomand.net
Sat Apr 4 20:07:37 EDT 2020


Andy et al;

Just quoted what is in the K3S manual.   No interpretation provided.   I 
agree that 100 watts key down is a lot for a SSB amplifier running in CW 
mode.   To me that says 100 watts for 10 minutes and then RX for 10 
minutes.   Otherwise equal TX and RX times.   Who does that?

I just pay attention to the PA temp when running digital modes. Likewise 
for the KPA500.

73

Bob, K4TAX

On 4/4/2020 5:01 PM, Andy Durbin wrote:
> "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."
>
> If you want to know what it actually means you'd probably have to run a test and record the PA temperature.  Does it reach maximum value within that 10 minute period?  If so, what is that maximum value and do you want to operate the finals at that temperature?  If temperature does not reach a maximum then what is the rate of increase?  At what time does the increasing temperature cross over the temperature at which you are willing to operate the finals?
>
> I record KPA500 temperatures for every transmission.  Unfortunately Kenwood does not provide finals temperature on the serial bus so I have to make do with recording my TS-590S rear chassis temperature.
>
> Kenwood provided data shows TS-590S final temperature limited at about 85 deg C after 5 minutes and remained constant for remainder of the 2 hour 100 W key down test.  (and no, I don't let mine get that hot)
>
> 73,
> Andy, k3wyc
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