Zzzap can see radio waves from the east coast

“There’s the other side of that coin,” said Danielle. “We don’t know they’re alone. For all we know there are military installations and population centers all over the country that are connected.”
“We have seen no evidence of such a thing,” said Stealth.
“And I’ve never heard it,” said Barry, waving his half-sandwich in the air. “Even if they were all on the East Coast, I’d see something in the air now and then.”

Excerpt From Ex-Patriots, pg 109
Peter Clines
https://books.apple.com/us/book/ex-patriots/id585738393