17 Mar
2013
17 Mar
'13
4:34 p.m.
Alan,
I believe the subcarriers you mention are the HDRadio sideband. I've tried
decoding this band but have been unable so far - it seems that iBiquity
holds their proprietary standards close and I guess the community hasn't
yet figured out how to decode it. If anyone is aware of an approach to
decoding HDRadio, I'd love to know.
http://en.wikipedia.org/wiki/HD_Radio
Ethan
On Sun, Mar 17, 2013 at 10:48 AM, Alan Corey <alancorey(a)yahoo.com> wrote:
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.
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?
Alan
-----
Radio Astronomy - the ultimate DX