A cartoon rabbit threatened shortwave listeners for four days
2026-07-06 · EA5IYR
Seven seconds after the top of the hour, on 19 December 2004, four shortwave frequencies began doing something odd.
A burst of data lasting 0.8 seconds. Then a voice: "Varmint, I'm a-gonna b-b-b-bloooow yah t'smithereenies!" — Yosemite Sam, lifted from the 1949 Warner Bros. cartoon Bunker Hill Bunny.
Then the same thing ten seconds later on the next frequency up. And the next. And the next. The schedule is the interesting part
Take the joke away and look at the engineering.
Four frequencies — 3700, 4300, 6500 and 10500 kHz — worked in sequence, low to high, ten seconds apart, the whole cycle taking exactly two minutes and starting precisely seven seconds past the hour. Transmitted in double sideband. Repeating for hours.
That is not somebody messing about with a transmitter. Frequencies spread over that range are chosen so that whatever the ionosphere is doing, at least one of them gets through — the same logic the US Air Force uses on four frequencies at once. Somebody wanted this received, reliably, by someone. Nobody has read the burst
The 0.8 seconds of data has been recorded thousands of times by listeners around the world. It has been analysed, stretched, spectrogrammed and argued over for twenty years.
It has never been decoded.
That is less mysterious than it sounds. Eight-tenths of a second is not much material, and if it is encrypted at all then no amount of listening will help — the same arithmetic that protects a numbers station applies to a data burst. Where it came from
Listeners with directional antennas triangulated the transmissions to the New Mexico desert. That is a region with a great deal of US government radio infrastructure in it, which is suggestive and proves nothing whatsoever.
It stopped on 23 December 2004 — four days — then came back in February 2005 on the old frequencies plus new ones, including some uncomfortably close to time signal stations. Then it went quiet. The most likely explanation is dull
The best guess anyone has offered is a transmitter test: somebody proving out equipment, needing a distinctive marker that would be instantly recognisable in a recording and could not be confused with real traffic, and reaching for a cartoon.
If that is what it was, the choice was good engineering. There is no mistaking it for anything else on the band.
Nobody has ever confirmed it, and after two decades nobody is likely to. It sits in the odd category of signals that are completely documented — you can hear the recordings, you know the frequencies, you know the schedule to the second — and completely unexplained.
---
Sources: Wikipedia — Yosemite Sam (shortwave)), HFUnderground — Yosemite Sam, SpyNumbers.com — Yosemite Sam.