SNR for satellite signals

I have worked on several satellite projects, such as SATCOM. Based on my past experience, satellite signals usually have high SNRs (or LOS signals) compared to cellular signals in the city environment, The received satellite signal's SNR would be approximately 10dB ~ 20dB, or even higher. I am currently working on a TETRA project, which would be some low earth orbit signals (terrestrial signals). What could be the range of TETRA signal SNRs? The received signal's SNR plays a very important role on the receiver structure design.