[Elecraft] Pwr<>Antenna

[n2ey at aol.com]

 Quoting K2VCO:
 
>Let's say you have a 1.5KW amplifier. Overall efficiency might be 50%, so it >draws 3KW key down. 
 
What does it draw key-up? 
 
>Now let's say you operate 2 hours a day, 5 days a week. During that time, you >QSO 50% of the time. During a QSO, you transmit 50% of the time and listen >50% of the time. You use CW, so your duty cycle is 50%. This will cost you >3KW * 10h * 0.5 * 0.5 * 0.5 = 3.75KWH, or, at the specified rate, about 48 >cents a week, or $25 a year if you always use the amplifier and don't take a >vacation.
 
Actually a bit more.
 
If the amplifier draws, say, 250 W key up (to keep the heaters hot, fans turning, and B+ caps charged) then you have an additional 8.75 hours x .25 = about 2.2 kWH. So the weekly total is really more like 70 cents a week.
 
Of course in most cases merely leaving a few lights on a few hours each day will use more kWH in the course of a year. 
 
 
>SSB will be cheaper.
 
How do you figure? The duty cycles are about the same. SSB may even have a higher duty cycle if you turn the processor on.
 
btw, the duty cycle of CW is about 44%: Consider the standard word "PARIS". With all the spaces, it's 50 time units long. But the key is down only 22 of those times. 
 
73 de Jim, N2EY