[Elecraft] k3 current

Don Wilhelm donwilh at embarqmail.com
Fri May 17 10:56:03 EDT 2019


Issac,

That current draw seems about normal to me.  To reduce the current draw, 
increase the power source voltage - 14.5 volts or so will reduce the 
current.
The K3 power control circuit is designed to maintain the requested power 
output - so more voltage equals less current for the same power.

There is a basic current draw for the low level stages in any radio, and 
that is a major portion of the 3.6 to 4 amps of your current draw at 10 
watts.  At the 13 watt level you have to add the idling current of the KPA3.
Above that 13 watts, you can assume about 50% efficiency for the PA itself.

73,
Don W3FPR

On 5/17/2019 7:02 AM, TL_Netvision wrote:
> Hi all
> 
>   
> 
> I am trying to understand power consumption of a 100W K3 (new synth., tuner
> off, no 2nd receiver) at various output-power levels.
> 
>   
> 
> 1.       Voltage read by the rig is 13.6-13.8 V at all times (power
> dependent).  This is OK.
> 
> 2.       Current as indicated by the rig at 4 power levels (band dependent):
> 
> A.      10W:  3.6-4 Amps
> 
> B.      13W: 9-9.5 Amps
> 
> C.      50W: 13-15 Amps
> 
> D.      99W: 21-22 Amps
> 


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