Out of curiosity, do you happen to know what kind of throughput we could expect on a simplex 2.8/2.5khz carrier? Assuming something like -75dbm SNR. I'm not familiar with anything modern that does bandwidths that small.

I ran the calculations for LTE in a FM radio station allocation a few years back and came up with something like 1.4Mbps on a CAT4 radio (no idea what modulation and FEC levels I assumed).