Why does ubuntu 14.04 only connect to a wifi network in close proximity to a router?

Question

WiFi

I installed ubuntu 14.04 on my laptop, the OS does not find third-party wifi networks, except for those that I already tried to connect to (without setting up new connections).
I noticed that you can connect to a wifi network if you are located two to three meters from the router. At long distances, after trying to connect to the network, the message "DIssconnect" pops up.
Realtek RTL8723BE 802.11b/g/n Wi-Fi Adapter

Answer 1

Did you turn off the microwave? To increase the power of the transmitter on the router ... Can the broadcast channel be set manually, after filtering out the freest one? and what do we know about the wifi interface?