Now, my LTE modem/router doesn't support a frequency lock. An oversight on my part, when I bought it a couple of months earlier.
That's an inconvenience, however, as the base station I'm using serves both LTE 800 DD and 1800 Mhz, and my router keeps switching between the two. Not sure why.
Anyway, I need to buy a router that supports a frequencey lock, so that i can lock down -- as it were -- to the frequency that provides the best speed.