Orbi 4G LTE … help please

Can anyone advise me wrt a new Orbi 4G LTE router please? I bought an aerial, connected it to the router, moved it around etc. But the speed test was rubbish. Disconnected the aerial and the speed test was the same as with the aerial attached. 

Do I have to tell the router that there's an aerial attached or is it able to work it out itself?

thank you in advance.