I live in India, Bangalore. I have an Airtel Huawei B310s-927 4G router. Since the network coverage in my area is very bad, I want to improve the 4G signal strength by using an antenna. But what antenna should I use? I tried searching elsewhere and found I can use an "SMA male" antenna, but what specifications Mhz? Can I buy a 900MHz SMA Male antenna?
Following is the instruction page of the router next to the router next to a USB drive for size.