Radio Wave, Electromagnetic Wave
Noun
でんぱ
このビルはコンクリでできてるので、む線の電波はとどきません。
This building is made of concrete, so it can't be penetrated by radio waves.
公きょうの電波でそんな事言うなんて、最低だね。
How could he say such things on public radio! Nasty jerk.
ごめん、よく聞こえないよ。ここは電波が悪いみたい。
Sorry, you sound kind of choppy. It seems like I’ve got bad reception here.
The electricity wave is a wave of electricity going through the air. There are many words one can use to describe this, but the easiest one is reception (aka the reception on your phone, for example). Other more technical meanings are radio wave and electromagnetic waves. Which one you like is up to you, but reception is going to be the most common meaning on the street. Luckily people in Japan don't have AT&T otherwise you'd hear this word a lot more...
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well. The は from 波 rendakus to ぱ, so be careful. Maybe it's your pa who has bad reception every time you try to call him?