I was doing some research on digital modes today when I came across this great JT65 power calculator:

http://dwestbrook.net/projects/ham/dBCalc/

Basically, you feed it your power level, for example, 5 watts, then input your signal report from a recent QSO, for example, -06, and the app will calculate how much power you actually needed to complete that QSO successfully.

Last night I parked on the 40 meter JT frequency and called CQ for a half hour or so. I had four stations respond to me, all from the US. The “worst” signal report I received was -06 from an Indiana station, with the best at -04 from a station out of Kentucky. Now, both of these reports are excellent as far as I’m concerned. When I run 2.5 watts and work Europe, I typically have signal reports closer to -15 to -18. So last night on 40 meters, I was definitely getting out with a “booming” signal.

And that’s where the calculator comes in handy. Did I actually need to run 5 watts to make stateside contacts? Heck no. According to the calculator I could have worked that Kentucky station with less than half a watt and would have still been comfortably heard. See the chart below:

Next time I work 40 again, it will be at much lower power, and hopefully reduce wear on the FT-817’s transmitter. But it’s also good amateur practice to only use a level of power needed to complete a QSO. Last night running 5 watts was just downright wasteful.