The only signal I can see is an unusual 2 tone one which alternates with a carrier in the middle of the 2 tones. The carrier is only there for ~2ms every 301ms. The comb extending from the 2 tones looks like an overload of the transponder (or a test). The SDR plot appears to show that the centre tone is present at the same time as the pair of tones, this is an artefact of the capture. They are mutually exclusive in time.
The centre frequency is 7397.2708MHz LHCP
This is how it looks on Crazyscan:
