[TenTec] Battery charger (power supply Hercules II)

[Jim Brown]

On 2/5/2011 2:20 PM, NL7VL wrote:
> I know that with CW you are actually looking at a 50% duty
> cycle

That assumes that you transmit 100% of the time, which is certainly not 
the case.  Rather, most of us listen more than we transmit, except, 
perhaps, during contests.  So for CW, a duty cycle on the order of 30% 
is pretty conservative.

> but I'm not sure about SSB.

The peak to average ratio of highly compressed speech is on the order of 
10dB, which is a 10:1 power ratio. If you subtract 2dB to account for 
varying efficiency of the output stage at different power levels, you're 
at 8dB, which is roughly 6.3:1 ratio. Applying a 50% listening factor, 
you're at an 8% duty cycle.

In all of those cases, I'd increase the current requirement by 10% to 
account for efficiency of the battery itself.

73, Jim Brown K9YC