A prominent advocate for the AM band is petitioning the FCC to allow stations to use all-digital transmissions in the United States.
Bryan Broadcasting Corp. on Monday filed a petition for rulemaking asking the commission to initiate a proceeding to authorize the MA3 all-digital mode of HD Radio for any AM station that chooses to do so.
Permitting such modernization would “give AM broadcasters a needed innovative tool with which to compete” without harming others in the spectrum ecosystem, it wrote.
Bryan is licensee of four AM stations, five FMs and six FM translators in Central Texas. Ben Downs is the vice president and general manager, and submitted the petition along with the company’s attorney David Oxenford of Wilkinson Barker Knauer. Downs also has served on the NAB board in the past, and he has been a vocal advocate for various regulatory steps to “revitalize” the AM band.
All HD Radio receivers in the market that have AM functionality would be able to receive such all-digital signals. But legacy AM receivers would not, which has long been a barrier to serious discussion of all-digital. Now, some observers say, the availability of FM translators for AM licensees has made something that once seemed unthinkable at least worth discussing.
There is one AM station in the country with special temporary authority to broadcast in all-digital. Hubbard’s WWFD in Frederick, Md., near the nation’s capital has been on the air since last summer. The station’s Dave Kolesar has been speaking in public about the ongoing experiment and will do so again at the upcoming NAB Show.[…]
A short excerpt:
“AM occurs elsewhere in nature. A lightning strike or manmade electrical discharge will produce a burst of electrical noise that varies in amplitude. Since AM radios are designed to detect variations in amplitude, this is why they are prone to interference from such things. AM held sway as the primary method of modulating a radio wave up to WWII, not only for broadcasting, but for all types of radio communications.
Every vintage consumer radio, be it standard broadcast or shortwave, up to WWII, received amplitude modulated signals. Nowadays, AM broadcast stations are associated with lower quality audio, but such was not always the case. Receiver design really came of age in the 1930s with the superheterodyne circuit and advancements in loudspeaker design. The grand floor consoles of the late 1930s leading up to WWII were capable of producing audio that was very good, even by today’s standards, the only exception being that they were monaural, as stereo technology was still a ways off.”[…]
Litwinovich’s article is a must-read as he gives a concise overview of amplitude modulation, AM vs. FM, and even covers current proposed uses of the broadcast band (something we’ve also recently mentioned).