Trev
The Dumb One
Similarly, I'm not convinced it's 4G. Far more likely, as well as what BH said, is the fact that the lower channels (CH31 and 37) are quite a bit 'out of band' for a C/D aerial (CH 48-68), thus reducing signal strength/S/N ratio even more than just that by the lower transmitted power of -6dB and getting on for -9dB. Seems at present the OP needs a group W wideband and then, ideally, after 2019 a group K (CH21-48)