OK2SAM, double spaced signal

Although I sometimes decode OK2SAM's WSPR signal, it always need to be strong...
On the attached file, OK2SAM signal is around -10 but getting no decoding. On the other hand the upper signal at 11:40z got decoded at -26 (the stronger one in the same period is 7L4IOU at -10.)
OK2SAM, if you ever read this post, please explain what kind of settings you are using to produce such a signal, resisting to WSPR decoder ! (You may also want to fix it !)

Regards
Patrick

PS: you may wonder how I know it is your signal: easy you are the only one having such a signal !