Data: FR 6400 Power Draw

The manual for my 6600M says it draws about 1.7 amps in receive.

The manual for my 6600M says it draws about 1.7 amps in receive.

The draw in TX is in two parts, A) the bias applied to the final amplifier and B) Output power.

Flex seems to use a near class A amplifier with increasing bias for higher power, lacking more detailed data, the ROUGH calculations, as I have witnessed with a FR 6700 and using the previously reported power levels:

RX: 43W total - 27W FR in receive = 16W PS overhead at 2A draw (PS power servicing the 2A (27W) FR draw)

TX at 10W CW Key down: 165W total - 25W PS overhead at 10A - 25W FR electronics without final - 10W transmit CW = 110W bias

TX at 100W CW Key down: 400W total - 45W PS overhead - 25W FR electronics - 100W transmit CW = 230W bias

These numbers demonstrate the FR final bias is roughly double the peak power output with a 100W minimum. This biasing keeps the final from producing clipping harmonics and other output distortions especially for SSB signals (as a much older CW amplifier does while running in class C)

Be thankful the FR produces such a clean output at such a low final voltage.