KDZR began as the "expanded band" twin to station KPHP, which broadcast on the standard AM band. On March 17, 1997, the Federal Communications Commission (FCC) announced that eighty-eight stations had been given permission to move to newly available "Expanded Band" transmitting frequencies, ranging from 1610 to 1700 kHz, with then-KPHP, also in Lake Oswego, authorized to move from 1290 kHz to 1640 kHz.[4]
The FCC's initial policy was that both the original station and its expanded band counterpart could operate simultaneously for up to five years, after which owners would have to turn in one of the two licenses, depending on whether they preferred the new assignment or elected to remain on the original frequency,[4] although this deadline was extended multiple times. It was ultimately decided to transfer full operations to the expanded band station, and on February 23, 2006, the license for original station on 1290 kHz, which had subsequently changed its call sign to KKSL,[5] was cancelled.[6]
On October 20, 1997, the new expanded band station on 1640 kHz first signed on, as KKJY. It aired a christian radio format, and was owned by Crawford Broadcasting.[7] On November 1, 1999, the station changed its call sign to KPBC while maintaining its religious format.
On August 13, 2014, Disney put KDZR and 22 other Radio Disney stations up for sale, in order to focus on digital distribution of the Radio Disney network.[10][11]
On September 15, the Salem Media Group announced it would acquire the last five Radio Disney owned-and-operated stations still available for sale, including KDZR, for $2.225 million.[12] KDZR was acquired through Salem Media of Oregon, Inc., for $275,000.[13] The Radio Disney format ended on November 27.[14]
The sale was completed on December 4, 2015.[15] KDZR returned to the air that same day, carrying a conservative talk format, branded as "Talk 1640".[16] On April 2, 2018, KDZR made some adjustments to its program schedule and rebranded as "AM 1640 The Patriot".[17] The move coincided with Salem beginning a local marketing agreement (LMA) to operate and program another Portland-area conservative talk station, KPAMTroutdale, which began calling itself "AM 860 The Answer."
On June 1, 2021, KDZR changed their format from conservative talk to regional Mexican, branded as “La Patrona 1640”.[18]