K2: Temperature of driver Q6 during keydown

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K2: Temperature of driver Q6 during keydown

Michael Linden
  Fine tuning of the PLL temperature compensation circuit requires transmit cycles of 15 minutes or so at 10 Watts. However, I've found that driver Q6 gets hot to the touch after just a few minutes of key-down. Is a transmit cycle of 15 minutes really a good idea?
   
    Thanks,
  Michael N9BDF, K2 #4137
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Re: K2: Temperature of driver Q6 during keydown

Don Wilhelm-4
Michael,

If you are talking of continuous key-down, that long a period could
cause a problem.  The K2 power should be limited to 5 watts for
continuous keying (or continuous duty data modes).
'Transmit cycles' of 15 minutes would be transmitting normal CW as in a
QSO - that places the maximum duty cycle at 50% and you can run 10 watts
easily.  Set a brick (or other appropriate device) on your dot paddle
and run it into a dummy load.

In most cases, you will not find a lot of improvement in the QRP K2
because the heat generating components are far away from the PLL and
thermistor area, but the heat does increase with the addition of the
KPA100 - more heat coupled with a smaller space.

73,
Don W3FPR

Michael Linden wrote:
>   Fine tuning of the PLL temperature compensation circuit requires transmit cycles of 15 minutes or so at 10 Watts. However, I've found that driver Q6 gets hot to the touch after just a few minutes of key-down. Is a transmit cycle of 15 minutes really a good idea?
>    
>
>  
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