She used an open frequency so the miners could hear.

They had tested the radios, keeping both on open frequencies.

Someone was going to have to contact that plane on an open frequency.

- you should not discuss on an open frequency, however secure.

Then the voice paused as if listening to itself, testing the open frequencies.

It would have to be on an open frequency, one that the rebels might be monitoring as well.

So, yes, there are issues with using the "open" frequencies, but they're not insurmountable.

The other had a radio that didn't appear to be picking anything up on its open frequency.

Richardson looked to make sure he was on an open frequency.

I can think of two more I'd use if we weren't on an open frequency.