KOPB-TV originally signed on the air as KOAP-TV, on February 6, 1961. The
call sign letters stood for "Oregon Agricultural Portland", preceded by the "K" prefix the
Federal Communications Commission uses when assigning call signs for stations west of the
Mississippi River. It was a sattilite station for KOAC-TV in
Corvallis, Oregon, whose call letters—carried over from KOAC-AM, which received them in the mid-1920s during its early years broadcasting as an AM radio station—stood for "Oregon Agricultural College" (
Oregon State University's original name). KOAP-TV was first housed in a leased building at what is now known as 2828 SW Naito Parkway, with the transmitter being located on
Council Crest. OPB was a pioneer in
HDTV. As early as March 5, 1997, OPB's experimental HDTV station transmitted a random-bit data stream. On September 15, 1997, OPB Portland was assigned the experimental call letters KAXC for channel 35. Then on October 11, 1997, at 4:37 p.m. KAXC became the first TV station in Oregon and one of the first on the west coast to transmit an HDTV picture. After experimentation ended, channel 35 was vacated. On December 7, 2001, KOPB-DT began operation on channel 27. ==Technical information==