<html><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:12pt"><div><span>This might be a better question for the Gnuradio list, but for years I've known that some broadcast FM stations actually transmit a second audio program which is somehow modulating a subcarrier in the main transmission. It probably carries mostly elevator music type junk but is rumored to be commercial-free (a rare thing in the US!). I remember seeing dedicated receivers advertised for this, but never actually bought one because I wasn't sure it was active in my area. These date back to Lafayette Electronics days I think and ever since so 40 years or more.<br></span></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: times new roman,new york,times,serif; background-color: transparent; font-style: normal;"><br><span></span></div><div style="color: rgb(0, 0, 0); font-size: 16px;
font-family: times new roman,new york,times,serif; background-color: transparent; font-style: normal;"><span>I've noticed (in SdrSharp) that on some FM stations I can see what look like they might be subcarriers on either side of the main signal. Anyone decoded those?</span></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: times new roman,new york,times,serif; background-color: transparent; font-style: normal;"><br><span></span></div><div style="color: rgb(0, 0, 0); font-size: 16px; font-family: times new roman,new york,times,serif; background-color: transparent; font-style: normal;"><span> Alan<br></span></div><div> </div><div>-----<br>Radio Astronomy - the ultimate DX<br></div></div></body></html>