I'be never had any problems getting KRXO in and around Tulsa because of 107.9. Or at least as far as I could tell any problems I've had getting KRXO weren't caused by 107.9. Of course, now I just use the TuneIn Radio app when I want to listen to KRXO in Tulsa! I understand there was also supposed to be an LPFM licensed to Sapulpa at 107.7, though, as far as I know, it's never been on-air. Even going through Sapulpa, I get KRXO on 107.7.
I do, however, agree with you about 107.9's reception around Tulsa. Going from the Brookside area to my mother's house near 21st & Yale, it starts fading in and out around 31st & Harvard. This evening, going from Cherry Street to Mom's, it was spotty most of the way. When it was Jazz Tulsa a few years ago, I always preferred streaming it through my phone, even when visiting family in Tulsa. The stream was stereo, and it didn't start dropping out when driving around town. As far as I know, the new incarnation of Jazz Tulsa isn't streaming right now.