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Yosemite Sam

Yosemite Sam is the nickname that has been given to a mysterious station that was first reported on December 19, 2004. It transmits on four frequencies:
3700 kHz
4300 kHz
6500 kHz
10500 kHz
All transmissions are in DSB, double side band. That is, they can be tuned in either USB or LSB modes. It's essentially AM with no carrier.

A transmission is made on one of the frequencies. Then ten seconds later, it is repeated on the next higher frequency, and so on. Since there are four frequencies, a transmission is made on a given frequency every 40 seconds. The entire pattern takes two minutes (120 seconds). Transmissions always start at an offset of 7 seconds, such as at 10:00:07 UTC. The timing of the transmissions seems to be excellent.

Each transmission starts with what sounds like a data burst, followed by the phrase: "Varmint, I'ma Gonna Blow Yah T'Smithereens" said by what sounds like the voice of Yosemite Sam, of the Looney Tunes cartoon fame. The clip is apparently from the cartoon "BUNKER HILL BUNNY", 1949. An audio clip of a transmission is here: ys.wav

The data burst is 800 milliseconds long.

Here's an example schedule:

3700          4300          6500          10500
15:40:57      15:41:07      15:41:17      15:41:27
15:41:37      15:41:47      15:41:57      15:42:07
15:42:17      15:42:27      15:42:37      15:42:47
15:42:57      15:43:07      15:43:17      15:43:27
15:43:37      15:43:47      15:43:57      15:44:07
15:44:17      15:44:27      15:44:37      15:44:47

Reception reports seem to indicate the transmitter site is likely in the desert SW USA. This is due to the fact that the 3700 kHz freq has been monitored during the local daytime in Tucson Arizona, as well as from other observations, taking propagation into account.

Sam vanished from the air around 1830 UTC on December 23, 2004.

From the ARRL Intruder Watch:

This is to inform you that the FCC monitoring station did provide us with an approximate area that the "Yosemite Sam" signal was coming from, and the local Official Observers and Section Manager have been notified. Hopefully they will be able to pinpoint the source for us. However, due to the holiday season it may be a while. The location was given as near Albuquerque, NM.

Sam has returned! Sam has been heard again in February 2005, on the old frequencies, as well as on WWV frequencies of 10 and 15 MHz (and perhaps others).