[Elecraft] Elecraft Digest, Vol 249, Issue 8 but using external 100 watt amp and K3 output reduced to driving external

[Jim Brown]

On 1/9/2025 3:22 PM, JOHN LAWRENCE via Elecraft wrote:
> I’ve used my K3 to drive my smaller external amplifier during CW contests such as FD with 100 watts output, I found setting up to save the K3 for high rate TXing exchanges at a lower duty cycle and stress so 500+Qs will keep full power as distributed at a cooler configuration W1QS

I've done this for about ten years, running a pair of K3s SO2R from a 
100Ah LiFePO4 battery pack, float charged from a repurposed Thinkpad PSU 
through an rf-quiet MPPT charge regulator. The K3 is cleaner IMD-wise 
(clicks and splatter) at lower power and higher battery voltage, and 
that battery chemistry stays above about 12.7V under load through a long 
contest weekend. Before I went to LiFePO4, the SLA lived just above 11V.

73, Jim K9YC