IBOC on FM…Just as Inefficient!


Now that In-Band, On Channel Digital Audio Broadcasting (IBOC-DAB), or low-definition radio, has arrived on FM in St. Louis, portions of the band are now suffering from interference from the IBOC sidebands; several channels have been wiped out because of it. Three of the ten FM stations broadcasting in IBOC are owned by the bully of broadcasting, none other than Clear Channel Communications. Three are owned by Bonneville International, two by Emmis Communications and one each by CBS Radio and the University of Missouri-St. Louis. The results of IBOC’s arrival on FM in St. Louis are presented here, measured at Hazelwood, MO using a modified Kenwood AR-304 AM/FM/FM Stereo tuner and an Antenna Performance Specialties APS-9B nine-element outdoor FM antenna:


Bonneville International: WIL-FM 92.3 St. Louis, MO WMVN 101.1 East St. Louis, IL WARH 106.5 Granite City, IL


Clear Channel Communications: KSD 93.7 St. Louis, MO KATZ-FM 100.3 Alton, IL KLOU 103.3 St. Louis, MO KMJM 104.9 Columbia, IL KSLZ 107.7 St. Louis, MO


Emmis Communications: KSHE 94.7 Crestwood, MO KFTK 97.1 Florissant, MO KPNT 105.7 Ste. Genevieve, MO


Radio One: WFUN-FM 95.5 Bethalto, IL


University of Missouri-St. Louis: KWMU 90.7 St. Louis, MO


CBS Radio: KYKY 98.1 St. Louis, MO


This is more proof that going digital is not a good idea for FM radio, either. Engineers who are supportive of IBOC (and the logic is seriously questioned by the vast majority of broadcast engineers) don’t seem to realize the damage they’re doing to first and second adjacent channel signals. Digital signals will only be capable of audio quality below FM quality. If you’ve ever made a cell phone call in a weak signal area…this is what IBOC will sound like in weak signal areas. Speech and music will be unintelligible. FM radio is already capable of multi-channel audio (it’s called Subsidiary Communications Services, or SCS). In addition, stations broadcasting in “HD Radio” have little or no Stereo separation on their analog signals. With no market for IBOC in the United States, then it’s no wonder the logic of the National Association of Broadcasters and the Corporation for Public Broadcasting is fatally flawed in this area. Analog is the only way to preserve the technical integrity of FM broadcasting.