[1]

HDRadio begins all night transmission on the AM Band

DXing on the band starts to suffer

On Sept. 14, the [2] FCC let AM stations start full-time HDRadio broadcasting after sunset. Reception check last night from Oceanside had KFWB-AM in LA, and KFBK-AM in Sacremento two stations on the AM band receivable in HD.
Locally, KOGO did not have the HD indicator on; however the roll out nationwide is expected. Mexico has objected to full-time HDRadio broadcast on the AM band claiming reception issues to stations adjacent to the HDRadio broadcast. For example, KOGO-HD would make AM 590 and AM 610 have hash sounds in the AM 600 night time pattern. The night time pattern for KOGO south of San Diego is extensive.

Previously, the FCC mandated that the digital transmission on AM had to stop at sunset and could begin at sunrise local time. Last winter, I was able to get KOA 850 from Denver in HDRadio prior to sunrise here. The listening to 840 and 860 AM was difficult as the HDRadio sideband hash was underneath the analog signals.

Stay Digitally Tuned as night time reception of distant and local stations on the AM band can become difficult …..