The past couple of mornings, I noticed a familiar white-noise-like hiss under the audio of the WBZ Morning News. Pre-iHeart, that hiss was a tell-tale sign the station was transmitting in HD on AM 1030. Now, supposedly, that's been turned off under iHeart, and the only other reason for the hiss would be if 'BZ were blowing out less than its full 50-KW flame, due to say, tower and/or transmitter maintenance, and I'm hearing thermal noise in my receiver. Anyone have any info?