210115_114630 144.174 Rx FT8 -17 -1.6 685 SIDE LOBE
This is probably the one real one of the bunch, actually! The odds of random noise decoding as a freetext message with sensible English in it are vanishingly small. This was probably from someone who worked someone on 2m FT8, and then after exchanging their grid squares, sent a followup message to ...
I'd say these are simply corrupt. Take for example:
210113_163545 144.174 Rx FT8 -17 1.3 1247 J06NQY A68ITS/R R QM30
A68ITS doesn't seem to be a real call, but if it was, it would be a UAE call. The grid QM30 is in the Pacific ocean, about 800 km off the coast of Japan. This is a pretty unlikely combination.
The FT8 protocol includes error correction ...
You have to provide the -i option to invert the signal in order to decode it properly. The lowpass filter is not really required as this is a quite strong signal (but does not harm either).
$ ./rs41ptu -i --crc -vx wav/20140717_402MHz.wav
bits : 8
channels : 1
[ 5047] (K1930308) Do 2014-07-17 12:32:13.999 lat: ...
I have version 2.1.0. Under File->Settings, select the General tab. There is a box marked "Show DXCC, grid, and worked before status" that can be check marked. I use that to identify stations I have worked before.
The distance of a point in the constellation diagram from the origin gives the amplitude while the angle each point makes with the horizontal axis gives the phase. PSK can't be the right option here because the amplitudes are different and we have the same phases with respect to the horizontal axis. However, in the case of PSK, we have the same amplitude and ...