I have just fitted an LHGG LTE18 due to the LHG LTE6 units being out of stock and thought this maybe a good solution however I seem to have a problem whereby the lte modem will only connect to the carrier (EE in the UK) if bands selection is left blank or band 20 is also selected.
Generally EE in the uk on 4G use band3 that has a 20mhz bandwidth which would normally give a usable download upload connection. but selecting this band only on the LHGG LTE18 results in there being no connection even after rebooting the device.
If band 3 and 20 are selected then it will connect but with band 20 being primary and band3 being the CA secondary connection, Band 20 only has a small 5mhz bandwidth and therefore download speeds maxed out at around 7mbps whereas a neighboring property using an LTE6 model is achieving 30-40mbps on the same mast without issue.

It seems that the carrier aggregation fails to aggregate correctly, I have tried to load the connecting to hopefully bring the second carrier into use but it does not seem to.

bothe router OS and the LTE Modem are running latest firmware and I have also tried cell locking but when the band 3 connection details are added it fails to connect at all.

The Cell tower covering this area only has bands 3 and 20 available.

I have reached out to mikrotik but the procedure would involve multiple trips back to site to aid with diagnosis (downloading multiple support files). So before we venture into this or return to replace this with something that works I wanted to check If anyone else is seeing this on the LTE18 models.

The site is a few hours away so trying to avoid multiple visits........