Listening to shortwave radio, in stereo

The JRC NRD-545 (Photo: Universal Radio)

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:

If you would like to receive C-Quam AM stereo on your SDR, check out this informative discussion thread on HF Underground.

Many thanks, Dave for sharing your recording!

Readers: Dave’s website has numerous in-depth radio reviews. I encourage you to check them out!

Pirate Radio Recordings: X-FM

"Turn up the radio, I hear Stereophonics!"

“Turn up the radio Jim, I think I hear Stereophonics!”

For your listening pleasure: three hours of the pirate radio station X-FM.

This broadcast was recorded this morning, starting around 2:00 UTC, on 6,950 kHz AM. X-FM can even be received in C-Quam stereo–something I have yet to try.

This is a 10 year anniversary broadcast of X-FM and has an excellent mix of music (everything from Indie rock to trance) and Redhat’s live commentary. Superb signal strength, too.

You can download the recording of X-FM by clicking here, or simply listen via the embedded player below (note that I included X-FM’s full seven minute interval signal/leader):

Standard Pirate Radio Disclaimer: Though X-FM is quite a professional pirate (is there such a thing?), this is a recording of a real pirate radio broadcast, and as such, may include colorful language. In general, if you are easily offended by the words, ideas, music lyrics, or music herein, you should slowly…back… away…