Hi, it looks like you are listening in on the 10th overtone or something, thats usually what it looks like then, also its way out of wspr band pass but that will probably sort when you get it going like it should be.
Dont know gqrx but as you can decode other stations thats a good indicator that your rx is correctly setup.
First thing that comes to mind, what speed of the xo for the 5351 are you using?? have you checked you have it corresponds to the speed set in the ict fw?
/Mikael
