Argh Marty, that’s a huge upgrade step 
Why not a fresh install?
Please make sure that the PPA points to the correct repository version and that you have no old versions lying around from 15.04 - and in particular no source installations.
There is a well known issue on 16.10 - even an official Ubuntu bug - that I tried working around as also mentioned by Josh. I have tested the PPA on a clean installation of 16.10, though not with limesdr, So it should be working but it may not.
At the end of the day, if you objective is to run gqrx on a stable system, do a fresh install of 16.04 and stick to LTS releases.