[Elecraft] K3/100 Voltage Drop when transmitting

[Don Wilhelm]

John and all,

A 25 amp power supply should adequately power the K3 at 100 watts - but 
check the K3 specifications if contemplating 100 watts for DATA modes. 
The K3 is rated for ICAS and not for continuous duty.

Also keep in mind that the K3 is a bit different than other amateur 
transceivers in the way it controls power.  The K3 attempts to maintain 
the power in watts rather than just the drive level when you set the 
power knob at 100 watts.
That means if the voltage drops during transmit, the K3 will increase 
the drive and maintain 100 watts.  It takes more current to produce 100 
watts at 11 volts than it does at 13.8 volts.

73,
Don W3FPR

On 2/25/2019 2:44 PM, john at kk9a.com wrote:
> I suspect the problem is the power supply and Don has some good
> suggestions. I am not sure what the actual K3 power requirements are.
> FWIW, Astron's are rated for ICS, if you really want 25 amps continuous
> you need a 35 amp linear power supply.