C-Quam AM Stereo | The SWLing Post

Many thanks to SWLing Post contributor, Dave Zantow (N9EWO), who writes:

Just how many MW stations in North America are broadcasting in “C-QUAM AM Stereo” these days?? I found this reference which appears to be the most accurate list around the internet.

http://www.meduci.com/stations.html

I have taken this list and have edited it and converted to a PDF file [click here to download].

Best way to catch a AM Stereo signal these days is with a SDR device. We have been using Bernd Reiser’s “SoDiRa” program (version 0.100 Preview 24) with a SDRPlay RSP1 and does an excellent job with C-QUAM AM Stereo decoding.

http://www.dsp4swls.de/sodira/sodiraeng.html

During sky wave nighttime conditions we received CFCO in Chatham Ontario well of late on 630 kHz in AM STEREO (country music format). Program also appears to have built in DRM and DRM+ decoding (we have not tested this part of the program). IMPORTANT NOTE : We found we needed to use the older EXTIO version 3.7 otherwise we encountered errors with OUR connected Windows 7 PC’s (your situation may vary).

Dan Robinson’s JRC NRD-545

Not to forget that the JRC NRD-545 receiver has “built in” AM Stereo decoding (AMS mode). One MUST use the phono jack “line outputs” on the rear panel connected to an external amplifier etc. It does NOT output via it’s headphone connector. Speaking of the JRC NRD-545, please see my web page for late important service information on my “Radio News” webpage.

http://webpages.charter.net/n9ewo2/news.html

Thanks for the tip, Dave!

The last time I listened to a C-QUAM AM stereo station it was with WNNC station owner/manager, Dave Lingafelt. We sat in his beautiful red Buick Reatta, parked at the station and transmitter site and listened to 1970s rock on 1230 kHz. Needless to say, it sounded absolutely amazing! Indeed, all of Dave Lingafelt’s stations (WNNC, WAIZ and WXRC) sound amazing.

To listen to an AM station in stereo is a real treat. Thanks for reminding us, Dave!

Spread the radio love

The JRC NRD-545 (Photo: Universal Radio)

Recently, my buddy Dave Zantow (N9EWO) told me that his Japan Radio Company JRC NRD-545 could natively decode Motorola C-Quam AM stereo (the “AMS” function). To be honest, I wasn’t aware that AM stereo had ever been an option on a tabletop receiver.

Of course, C-Quam (Compatible—Quadrature Amplitude Modulation) was intended to be used on the AM broadcast (medium wave) band. It was one of several techniques AM broadcasters championed in the mid to late 1980’s to transmit and receive AM stereo.

Incidentally, AM stereo never really caught on. Much like DRM (Digital Radio Mondiale), AM stereo was being transmitted by broadcasters, but there were very few stand alone receivers on the market that could decode the signal. To make matters worse, there were at least five different AM stereo formats being promoted simultaneously and they weren’t compatible. In the end, C-Quam was the most widely adopted.

Of course, C-Quam can be used on the shortwave bands as well, providing there’s enough signal to make a stereo lock. On December 1st, 2013, Dave recorded the shortwave radio pirate XFM who routinely broadcasts in C-Quam stereo. Note that XFM‘s signal was marginal, thus you’ll hear the stereo lock slip several times. Still, pretty amazing to hear:

When Dave sent his recording to XFM, he was told that it was the first stereo recording they had ever heard from a “stand alone” type receiver. Most listeners who listen in C-Quam do so with an SDR like the Perseus.

Here is a good example from YouTube: