Question about Huawei B535-232

The router itself is great and can also pick up weak signals. I have also tried several external antennas, but did not really have the feeling that the antennas brought an improvement... Firstly, I tried using small amplifier antennas directly on the router and once with an external antenna with cable over the balcony. Since neither of these brought any improvement, it could also be that I forgot to change something in the device so that it takes the signal via the antenna...