Mysterious Yosemite Sam Transmission

The Yosemite Sam signal is an AM broadcast which has been happening like clockwork since February 2005. It was first reported on December 19, 2004, but went off the air 5 days later and did not start back up until the following February). It is a recording of Yosemite Sam saying: Varmint, Im a-gonna b-b-b-blöow yah tsmithereens!\r
The transmission is sent from somewhere in the southwestern desert of the United States, and begins at exactly seven seconds after the top of the hour. It is repeated on 4 different frequencies in ascending order, and exactly 10 seconds pass before the transmission is repeated on the next frequency. The processes is then repeated twice, and therefore takes 2 minutes to complete.\r
Here are the frequencies:\r
3700 kHz\r
4300 kHz\r
6500 kHz\r
10500 kHz\r
The sound clip was apparently taken from the 1949 cartoon Bunker Hill Bunny, and is preceded in the transmission by an 800 millisecond data burst.\r
It is believed that the broadcasting station is somewhere near Albuquerque, New Mexico, which is interesting because in many episodes of Merry Melodies Bugs Bunny would become lost and repeat the phrase: I knew I should have taken that left turn at Albuquerque.