GNU Chirp Sounder 1.23

During the gnuradio conference hackfest last week, I migrated all of my gnuradio blocks to the cmake build environment and gnuradio 3.7. As a consequence of this, GNU Chirp Sounder was also updated. I also wrote a new adaptive filter block to remove HF broadcast band signals.

The new version can be downloaded here: http://www.sgo.fi/~j/gnu_chirp_sounder/

I've attached a plot and a video that resulted from testing the migrated code. It shows chirp sounders presumably in Virginia and Puerto Rico. The receiver was located in Boston.

A sounder possibly in Puerto Rico. The new version has a feature that reduces HF broadcast band noise in amplitude domain before chirp downconversion.