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Letter to the Editor: AM Stereo Is Still an Option

Want revitalization? Mandate AM stereo in any FM stereo radio.

The website of WION(AM) in Ionia, Mich., promotes its AM stereo service.

A recent Radio World article about an AM monitor receiver included the author’s comment, “No, analog AM stereo is not making a comeback.”

Please know 100 stations in the United States still broadcast in C-QUAM AM stereo, and there are more returning. A Class B AM station in the New Orleans market will be starting C-QUAM as I write. There is one in Texas and more thinking about it. Australia has announced four stations there will be begin C-QUAM stereo transmissions in the next month or two.

It’s a shame that auto receiver manufacturers do not include C-QUAM in their products. But thousands of AM stereo car radios are still in use in Australia. In the U.S., that number will likely be higher since cars are now peaking in their lifespan, averaging as much as 17 years; with over 250 million on the road, that can mean a fairly large number out there still with a C-QUAM-capable radio, not to mention that certain HD car radios can decode C-QUAM, though not in wide bandwidth fidelity.

The HD Radios only need some code written to decode it and open up the bandwidth for full analog fidelity while also doing DSP-based noise blanketing to reduce static noise and do signal-based adaptive bandwidth so the adjacent channel is not a problem on weak signals.

Wanna hear AM stereo? Go to WION’s web site and listen to their stream off their Carver TX11B receiver.

If the FCC really wants to do AM revitalization, they should and could issue a mandate that AM stereo be included in any FM stereo radio and include AMAX performance plus DSP NB where applicable.

As a former AM stereo owner (KLLS facility 31108), I found people want to listen to AM with a good format, especially if they have a decent receiver. I had people with 1990s cars with C-QUAM radios enjoying the rich full sound of my AM stereo station. It can be made to work with today’s technology, if my years of being associated with Land Mobile Radio and experts on noise abatement like George Munsch, W5VPQ (formerly with GE, who wrote the book on the subject for the U.S. Navy!) has taught me.

A decent noise blanker can take a noise situation down 20–40 dB. I experienced such with Midland LMR FM radios on VHF low-band FM; they even outperformed Motorolas! Now if that can be done on a 20 kHz wide FM signal, I’m sure at medium-wave the technology can work with a 20 kHz AM signal.

The opinions expressed here are not intended to represent those of my employer; this is my personal opinion as an engineer for 40+ years, a former AM C-QUAM station owner and group admin of the Facebook group AM Stereo C-QUAM.

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