The Virtual channels for the most part are the (Legacy channel number) the channel number that the Tv station had when the station was transmitting Analog before the digital change. Some Tv stations continued to transmit on the same channel , most did not. The Tv stations continue to show the Legacy channel number because they see it as brand identity. The Real channel number is the REAL Tv Channel that the Tv station is transmitting. One needs to know the Real channels so as to use the correct antenna. . The Tv stations need to drop the Virtual number completly and have the Real channel number as the brand identity.
http://www.rabbitears.info has some comments about Real and Virtual channels.