Neighbour got a new spark smart modem 2 today and I've been conscripted into assisting.

We are semi rural and broadband for him is 4G. Prior to the new Smart Modem he had the previous generation Spark Huawei branded 4G modem.

We have very poor / no cell phone coverage, but with a Yagi antenna on the roof, up until a week ago his 4G broadband connectivity was good. Then is performance dropped off to almost nothing.

He went to the Spark shop and the assistant told him his problems were due to his old modem and sold him the new smart modem 2.

The new one doesn't work at all. It gets very poor connection, red light. The RSRP/RSRQ/SINR values (whatever they are) are -121  / -14.0 / -6.0 

The unit itself does work ok though, we drove up to the top of a nearby hill that offers cell coverage, powered the modem via a portable generator and all worked as advertised.

The user interface doesn't seem to have any way to select external antennas so I'm assuming its automatically selected.

Does anyone know how the antenna selection works? If an external antenna is sensed, does it automatically switch to it and stay with it.

I'm suspecting it is not sensing the external antenna at all, but can't be sure of this. There seems no way to determine if it's using internal or external antenna. 

I'm half thinking the root cause could be with his antenna cable or the yagi, but I don't have a way to test these.

thanks in advance,

dave