Radio Thailand's 15590kHz/9390kHz are by far the strongest, steadiest, most consistent signals on shortwave at my location. The PL880 often shows a 50-65dbv signal level, sometimes stronger and a S/N ratio of 05-20, usually in the low teens.
Two recent loggings, with audio:
Radio Thailand World Service in English 15590kHz on October 13, 2016 from 0000 to 0100UTC (4pm to 5pm) local time. National Thailand and international world news with several sponsor ads.
SINPO Rating: 55455
Audio here:
https://youtu.be/ETAkwLWu4scRadio Thailand World Service in English 9390kHz on October 9, 2016 from 1900 to 2000UTC (11am to 12noon local time.) National Thailand and international world news with several sponsor ads.
SINPO Rating: 55555
Audio here:
https://youtu.be/pPeGwFCQ9FcLocation: Galena, Alaska. Rural Central Interior, 300 miles west of Fairbanks and 300 miles east of Nome.
Equipment used: Tecsun PL880, Wellbrook ALA1530LNP, DXEngineering HF PreAmp and EmTech ZM2 Antenna tuner.