SDR Recording of WWFD-Am Radio, Frederick MD?

3 points

5 years ago

All-digital AM is an accepted, but not widely-used, standard. It could make the AM broadcast band better suited for music and performance, instead of just talk.

As far as I know, WWFD-AM radio, 820 kHz, based in Frederick MD, is the only fully digital AM broadcast radio station in the US. A radio amateur based in Mayland or Washington DC, using SDR techniques, would be well-placed to make an I/Q recording of WWFD and share it so that the rest of us can study the format.

Here is something to shoot for:

- record I/Q samples (not Q-branch), so that signal structure and phase information is preserved - from on-air digital WWFD-AM, not the repeater on WWFD-FM - preferably a recording that crosses the top of an hour (includes a time hack and station call) - sample passband of 22 kHz centered on 820 kHz (809-831 kHz) or wider (captures adjacent sidebands) - sampled at 45,000 samples/sec or faster, for about 300 seconds or longer - share on GitHub or the like, and notify https://github.com/theori-io/nrsc5 (for whom I do not speak)

A 300 sec recording should come in under 100 MBytes. Recordings from various times and locations would be welcome.

Please help make this request better with your suggestions. Thank you!