Dr. Pedro E. Colla (LU7DID)
The power meter is a cheap one, I didn't opened it but I assume it's rms voltage sensing with some assumptions on how to change it into a power meter; the value yield it's very low in my case, but I don't think it has anything to do with the waveform.
My computation was using the value provided by Adam as being the typical to be found (17 Vpp) and aplying an approximation to compute the rms voltage from it and the power from it, this computation yield 700 mW over 50 Ohms.
Both are approximate figures.
73 de Pedro, LU7DID