[Elecraft] Boost power supplies for RF amps

[Bill Frantz]

On 2/20/17 at 5:35 PM, jackbrindle at me.com (Jack Brindle) wrote:

>To be fair, we have had one instance of the problem, and that 
>station was running the battery critically low. In fact the 
>battery failed at that voltage (something like 10 volts) and 
>had to be permanently removed from service. Perhaps the answer 
>is to take the battery manufacturer’s advice and not to run 
>the batteries below 11.5 volts. I believe the K3 has a 
>low-voltage alarm that can be applied to the problem so that it 
>gives a warning at the critical voltage and won’t continue 
>until the power is corrected.

Thanks for reminding me of the details. The 100W CQP incidents 
and the 5W FD ones get blurred in my mind.

Yes, the K3 has a low voltage warning. The level is controlled 
by the "BAT MIN" CONFIG menu setting with a default of 11V. It 
sends out a beep tone and flashes BAT LOW on the display. If you 
use a boost regulator like the TG Electronics Boost Regulator, 
note that these may introduce a junction voltage drop which will 
cause the warning to sound at a higher voltage.

73 Bill AE6JV

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