IT on the road

Any experts out there re IT on the road? I run a Telstra 4gx Aircard, and its haemorrhaging every time I leave the signal. Thrashes itself it death if the signal is low to zero, and goes into a lockup, uses all the battery etc. So external aerial, and I have one- 7.5 DB, bulbar mounted (way too low for my judgement)

But the patch cable is the wrong one apparently, spoke to a very clued up visitor at the camp site, he directed me to
https://www.telcoantennas.com.au/
and I ordered some patch cables etc.
Seems 4g mobile modems like 2 antennae's, not one. I have 2 of them, but not here, one is one the way. Will try it with the one on the truck, and the one in the mail (once it gets here)- and the 2 correct patch cables. Do 2 dissimilar aerials work ok? One is bulbar, the other is a magnetic roof jobbie

But regardless of the DB rating of the antennae, I am told that height is everything, put it up high by whatever means? Any experiences? Can a lesser Db antennae work ok (stationary) at increased height?
We are heading back to civilisation, Hitch issues etc, and I am determined to sort this. What do I buy? I have a mate with a basic magnetic aerial on the roof, and an old phone that has an external aerial socket that romps in? He is currently at Kilcowera Station and has a very good signal
I don't want a big bux solution.
We really, really need halfway decent IT as we have a couple of businesses. I am aware that when there is no signal, there is no signal. But Telstra have done a pretty good job of spreading it round.
thanks in advance
Jim