ION Media said it conducted two successful mobile DTV field trials in Chicago and Denver, at WCPX-TV and KPXC-TV, respectively. Harris, LG and Zenith provided the receivers and transmission gear for the tests. All three have been integral in developing the mobile broadcasting technology, including a standard for transmission, which is being vetted by the Advanced Television Systems Committee.
Stations affiliated with networks other than ION in Raleigh, N.C. and Baltimore have previously conducted mobile DTV tests. There is some concern about the required bitload to transmit receivable mobile DTV. In Raleigh, 4.5 Mbps--about one-fifth of a broadcaster’s total bandwidth--was necessary to transmit signals at 600 and 300 kbps.
In the ION tests, both stations were simultaneously transmitting two mobile DTV streams as well as four multicasts, within the roughly 19.4 Mbps pipe of a 6 MHz TV channel. ION did not include the breakdown allotted to each in its release.
WCPX transmitted from atop the Sears Tower, and KPXC, from a Fort Lupton, Colo.-based tower. Receivers included handheld mobile phones, laptops fitted with USB receivers, and screens installed in traveling test vans throughout the areas.
