In these longer nights of winter, the AM band is especially cluttered with the hissing of IBOC carriers slopping over two stations above and below the licensed carrier frequency. Before the FCC cleared the way for nighttime authorization of IBOC back in 2007, there was no issue of getting stations one or two frequencies up or down from a local 50,000 watter. For example, one local station, once the "cream of the crop" (pre-IBOC) in terms of high fidelity audio today sounds no better than the best dialup POTS line. The brickwall filtering mandated by IBOC operation really attenuates any audio higher than 4K to 5K cycles. This is to "protect" the IBOC digital carriers. Prior to IBOC, I had no problem whatsoever listening to 1010/WINS, KDKA or 1050/WEPN. The three CBS stations at 1010, 1020 and 1030 are basically having a slugfest every night trying to be "channel master" with their high powered IBOC signals splattering each other. The noise is deafening. Many other AM signals from other radio markets running IBOC at night cause considerable damage to adjacents many hundreds of miles away, even when you cannot hear the main carrier frequency clearly itself. AM HD does not work. It was a great try to digitize the AM band. But the results (the hissing factor) speaks for itself. If even a 50,000 watt IBOC station cannot be heard in crystal clear HD Stereo (without dropping out to mono) within 15-20 miles from its' transmitter site, that pretty much says it. It's not worth the investment. AM would be better off without IBOC and without NRSC filtering/pre-emphasis (pre-1990's). The IBOC radios with AM Stereo ability could be re-purposed for better fidelity (mono or Stereo). Many people have put a considerable investment for their AM plants. Those without IBOC are capable of much higher fidelity than radios produced today are capable of reproducing. The efforts of the station owners have been thwarted by the radio manufacturers who put virtually "zip" into their AM sections of the radios and by the use of AM IBOC to destroy what little high-fidelity there was left on the AM band. FM IBOC is a forgone conclusion. It will either sink or swim within the next two years. Given the lukewarm "reception" of sales (pun intended), well...... you do the math. There's got to be a better way of go digital without interfering with adjacent channel stations, both AM and FM.