Wiktionary
adv. (context idiomatic English) In rapport or complete accord.
Usage examples of "on the same wavelength".
Rhodan and Bell were communicating on the same wavelength, since that was how the Arkonides of 10,000 years ago had designed the system.
When they do, then both the spirit and I are on the same wavelength.
It was the only time I ever felt we were on the same wavelength -- and then for only an instant.
Any sign that they were on the same wavelength felt doubly welcome.
Selby never quite seemed to be on the same wavelength as everyone else.
But if you'll pardon my saying so, it's pretty obvious the two of you just aren't on the same wavelength, and I don't think it's because you haven't tried.
And these unknown people did not even risk anything while putting us onto their scent for it will be found and traced only by those who vibrate on the same wavelength.