to Block RF from outside such as WiFi of the neighbor, cell tower(近隣からのWiFi、携帯電話の電波塔などの高周波=ラジオ波からの防護のため)
one of the solution is put paint on your room especially bed room
Using Y shiled is a good way.(寝室をYshieldというペンキで塗るのは良い方法です)
I paint my bedroom with this.(我が家もぬっています)
Click here for the best prices of radiofrequency Y shield(ここから購入できます)
how to use Y-SHIELD
for grounding fabric (アーシングのための銀繊維布)
Click here for the shielding fabric
I personally use this one for bedding.
ArgenMesh
for windows 高周波ブロックのための窓のフィルム
Click here for the best window films()
I use SCOTCHTINTTM SHIELDING WINDOW FILM