Read this: On March 5, 2005, CBC Television launched a high definition simulcast of its Toronto (CBLT-DT) and Montreal (CBMT-DT) stations. Since that time, the network has also launched HD simulcasts in Vancouver (CBUT-DT), Ottawa (CBOT-DT), Edmonton (CBXT-DT), Calgary (CBRT-DT), Halifax (CBHT-DT), Windsor, (CBET-DT), Winnipeg (CBWT-DT) and St. John's (CBNT-DT). CBC HD is available nationally via satellite and on digital cable as well as for free over-the-air using a regular TV antenna and a digital tuner (included in most new television sets) on the following channels:

Where is CBC available for free?
What is the answer? (If it cannot be answered, return "unanswerable")
over-the-air