My SOTA friend and collaborator Andrew Moseley VK1AD has proposed a QRP challenge for 2017. He is going to aim to use 2.5w when activating summits during 2017.
I have started to do the same and my activation at Mt Ginini on 27th December was made at 2.5w for SSB and 0.5w on CW. I made about 20 contacts and although some chasers found lower signals a problem, I not only qualified the summit on several bands, I also qualified with CW at 0.5w. One contact was with Steve VK7CW who also used an FT817 at 0.5w, the lowest power setting of the radio.
The radio used was an FT817, powered by an internal LIPO 3S battery (windcamp). I had a spare battery but it was not needed. The 817 will not be as efficient in terms of output power/DC power consumed, as the bias current on the final amplifier stage will remain the same as it would be at 5w.
A fringe benefit from using lower transmitted power is that battery life will be improved. I had previously used the 817 with the internal battery at Mt Mundoonen on 26th December for a short activation. I did not recharge the battery after that activation as it was only used for 5 contacts plus some listening. After the Mt Ginini operation, the battery voltage according to the meter on the 817 was above 11v. It can go down to 10v without any problem for the 817.
Although we were on the downward slope of sunspot activity, making HF communications less certain, there are still sunspots and occasional sporadic E openings on HF bands.
It will be interesting to see how the QRP challenge goes during 2017. Progress reports will be made by both Andrew VK1AD and me.