The High Frequency Active Auroral Research Program (HAARP) in Gakona, Alaska, will soon undertake its first scientific research campaigns since the facility was taken over by the University of Alaska Fairbanks (UAF) Geophysical Institute 18 months ago. Among the investigators is UAF Researcher Chris Fallen, KL3WX, who will be working under a National Science Foundation grant, “RAPID: Spatiotemporal Evolution of Radio-Induced Aurora.” Fallen says the HAARP transmissions will take place within the facility’s transmitter tuning range of 2.7 to 10 MHz and should be audible outside of Alaska and may even produce visible effects within the state.
“This time my experiments will largely focus on artificial radio-induced airglow that potentially can be photographed from nearly anywhere in Alaska — weather permitting,” Fallen told ARRL. “I plan to start and stop each experiment block with an audio Luxembourg-style broadcast — transmitting two amplitude-modulated carrier waves at different frequencies separated by about 1 MHz, with the resulting skywave signal being a mix of both frequencies.”
Fallen said that he has prior success reproducing the “Luxembourg effect” using two DTMF tones. “But this time, I have a short simple musical composition recorded by a local musician,” he said. “It was composed specifically to take advantage of the Luxembourg effect.”
According to UAF, Fallen, an assistant research professor in space physics, will create an “artificial aurora” that can be photographed with a sensitive camera within Alaska. The phenomenon has been created in the past above HAARP during certain types of transmissions.
Just which HF frequencies Fallen will use won’t be determined until shortly before he begins his research. “The specific frequency chosen during a particular experiment depends on the experiment’s objectives, FCC regulations, and ionospheric conditions at the time,” Fallen explained. He will use ionosonde data to guide frequency selection.
In an explanatory blog, Fallen explains that HAARP scientists use the ionosonde to estimate two important parameters: (1) the amount of low-level ionosphere D-region HF radio absorption that frequently occurs due to natural, but not well understood, processes that prevent HAARP radio wave energy from reaching the higher ionosphere E and F regions; and, (2) the ionosphere vertical “critical frequency” [sometimes referred to as foF2], above which any radio transmissions pass through the ionosphere into space rather than being reflected or absorbed.”
Fallen said experiment times and frequencies for his airglow and Luxembourg experiments will be updated on his blog and on his Twitter account linked in the blog. He encourages radio amateurs and SWLs to record the events they hear and post reports to social media or e-mail him.
Built and operated by the US Air Force until August 2015, HAARP includes a 40-acre grid of antennas and a very high-power array of HF transmitters to conduct ionospheric research. Scientists later this month will use HAARP to conduct other experiments that will include a study of atmospheric effects on satellite-to-ground communications and over-the-horizon radar experiments.
Research funding agencies also include the US Department of Energy’s Los Alamos National Lab and the Naval Research Laboratory. HAARP also has a Facebook page.