I found similar performance with my new Ltap-Mini. Bought it to "upgrade" my 5Mbps DSL and bundle both lines.
I do have relative good LTE (compared to my DSL
) and get on 3 years old LTE phone 10+ Mbps.
I thus kicked of my first LTAP-Mini speed test on same network and SIM card and BANG 1.5Mbps!!!
Coudn't believe it and was extremely dissapointed. Same if I put the device outdoor!
(indoor test was via ethernet to Ltap, outdoor via Wifi)
Based on your advice I disabled via the GUI the band 20 and now it works in band 1 and 3 with so-so speeds (6-7Mbps).
Will try modifying the antenna setup now with ext. antennas from another LTE router device as I really want something above 10Mbps at least!
Do you know if there is anything else that can be done to improve perf (reduce Wifi power or switch of the Wifi i/f completely?).