Complex sentence: Therefore, one is offered in standard definition on WGFL's second digital subchannel (UHF channel 28.2, virtual channel 53.2 via PSIP) to serve as that purpose, which broadcasts from a transmitter in Newberry.
Split into simpler sentences: Therefore, one is offered in standard definition on WGFL's second digital subchannel to serve as that purpose. That airs on UHF channel 28.2 (virtual channel 53.2 via PSIP) from a transmitter in Newberry.