KUP was the point-to-point station of the San Francisco Examiner newspaper. It was open to private correspondence only with no fixed hours of service. It used A1 emission on 5585kc, 6530kc, 8230kc, 11170kc and 16460kc. It was presumably located in the offices of the newspaper in downtown but the ITU "Berne List" for 1930 shows it only as being in San Francisco, with no geographic coordinates indicated. The station does not appear in the 1932 list.
Interestingly, the Examiner was also licensed for station KUO which operated on 435kc and 500kc and was also open for private correspondence only. That's not too odd but if the 1930 Berne List is to be believed, KUO used A3 emission! They probably meant A2.
The photo below, the only one known of KUP, shows a member of the Byrd Antarctic Expedition at the station. The expedition held licenses for several stations including Main Base KFK which operated on 375kc, 400kc and 500kc in addition to 12 HF frequencies and Main Base WFA which operated on the same frequencies. No geographic coordinates are given for these stations.
The expedition was also licensed for Sub Base WFD and Sub Base WFE which operated on the same frequencies as KFK and WFA.