@neilh20 – thanks for your very detailed post and information!!
I hadn’t really considered the relationship between connectivity and packet size. I do have some issues at some of my sites with connectivity but always thought about it in terms of local interference. About half of my sites are buoys and someone has suggested to me that the ground plane of the water can interfere with the cell signal reception, but I’ve not had time to test that out. I’m also saving the data to an onboard SD card so, theoretically, nothing is being lost when I drop the cell signal.
I did look at the site you described as being the worst for connectivity TUCA_GV01, downloaded and graphed the RSSI data just to get an idea about what the worst might look like and notice that it seems to drop out beyond about -80 and seems to have improved over time, although I’d really have to put a little more work into the graph to prove it.
I’m not capturing regular RSSI data from my sites but it looks like that would be a good piece of info to trend, so I’ll have to look into modifying my code to get it. Assuming RSSI is a significant parameter, are there particular ranges for what you consider excellent, good, and poor?