[Discuss-gnuradio] NOAA Weather Radio receiver flowgraph

Someone on IRC had asked about building a NOAA Weather Radio (NWR)
receiver flowgraph for an RTL-SDR.

Since I had time, and no chores :), on my weekend, I came up the
attached flowgraph that handles the WX1-WX7 using an RTL-SDR.

It doesn't do the digital decoding of the NWR Specific Area Message
Encoding (SAME) data. Also, since the WX stations are a continuous
broadcast, there is no squelch and no volume control.

However, the flowgraph does have automatic frequency control (AFC) to
track with crummy RTL-SDR units, like mine, that are off frequency and
drift around.

Regards
-Andy