Hi friends. I have a weird problem with my Unifi TV. Whenever is is showing an HD channel, my 30mbps internet will go down to around 18mbps. I am using the Netis DL4480V modem / router from TM. The max speed I can get in my area is only 30mbps because of high rise building. What could be the problem? Is the building copper lines causing this? Or something wrong with the modem?