"Open" is a little subjective. We may all agree that a channel with a full power DTV is "closed", and a channel without any station within 150 miles is "open", yet the combination of intense tropo and nulling with a directional antenna could reveal another station on a "closed" channel and a station hundreds of miles away can still be a "pest".
Originally Posted by amfmtvdtvbrla
When the DTV transition was complete, many channels that had been closed became open to DX. In my case, Channel 25 had stations in Saginaw and Cleveland. After transition, the closest 25s were in Toronto and Pittsburgh.
Repacking involves moving existing stations to other channels more than stations being auctioned off.
After the repack, most people (perhaps not most of the USA' s land area) will have a station within 100 miles of them on EVERY UHF channel. Really nice ducts that allow one to DX a distant
Comparing Sporadic-E skip to skip on the AM and shortwave bands is like comparing apples and oranges.
Comparing tropo to skip is like comparing apples and bacon cheeseburgers.