The High Frequency Active Auroral Research Program (HAARP)
isn't your grandfather's HAM radio. Although this 3.6 million watt radio transmitter is best known for its ability to create ELF waves to signal submarines, HAARP is also used as a radio telescope to probe our Moon, Sun, coronal mass ejections, comets, and other space phenomena.
Generation of ELF/VLF Waves:
Much of the research at the facility is focused on the generation of ELF/VLF
because of the value of these frequencies to the Navy for undersea applications. Propagating radio waves in the ELF/VLF frequency range are generated at the lower edge of the ionosphere when high-power HF radio waves modulate the conductivity of the ionospheric D and E layers in the presence of a background or “electro-jet” current. The practical utility of this technique for communication systems is dependent on improving the efficiency and reliability of this process. A recent experiment was performed at HAARP to study the scaling of the ionospherically generated ELF signal with power transmitted from the HF array. Results were in excellent agreement with computer simulations confirming that the ELF power increases with the square of the incident HF power. Furthermore, no saturation effects were observed indicating that greater ELF generation efficiency is possible with greater incident power. 
The interaction of high-power radio waves with the ionospheric can produce faint optical emissions at specific wavelengths. Recent experiments at the HAARP Gakona Facility investigated the role of the HF beam pointing direction on the production of artificial airglow. The exciting result was that by pointing the HF beam directly along a geomagnetic field line, artificial emissions of greater than 200 Rayleighs (R) at 630.0 nm and greater than 50 R at 557.7 nm could be produced. This intensity was nearly an order of magnitude larger than that produced by heating directly overhead. Weak emissions of approximately 10 R were observed with effective radiated power (ERP) levels as low as 2 MW. These measurements have been repeated in other research campaigns with observations over a wide range of ionospheric conditions.
Figure 6 shows the artificially generated emission at 557.7 nm that was obtained using the NRL CCD imager during one of the experiments. (The imager used in this research uses a high resolution, cooled CCD. It was developed by NRL’s Plasma Physics Division and on loan to HAARP for the experiment.) 
In a bistatic configuration, HAARP directs signals at heavenly bodies and a secondary site, usually a receiving antenna array, receives echos from these broadcasts. In the following research projects we will see HAARP team up with the Long Wavelength Array (LWA) in New Mexico, the NASA WIND satellite (HAARP-WIND), and the Low Frequency Array LOFAR (HALO).
Some of these experiments have been done in collaboration with the NASA-WIND satellite and its HF radio wave receiver (the WAVES experiment). The unique orbit of WIND has provided a wide range of radial distances from Earth, including lunar flybys, over which we are able to study the interactions of radio waves transmitted from HAARP. The HAARP-WIND bistatic configuration has allowed new techniques for conducting HF radar experiments beyond the Earth's ionosphere. Other experiments are to be conducted with ground-based receiving arrays, such as the Wink. HF array, operated by the University of Texas. We are also planning future experiments utilizing the Low Frequency Array (LOFAR) that will provide a large collecting area array for radio astronomical research. 
HAARP-WIND, HAARP-WAVES Lunar Radar Experiment
A specific example of a recent experiment is given in Fig. 3 .and WIND spacecraft on September 13, 2001, when the :spacecraft was approaching the Moon to use lunar gravity for orbit perturbation. In a 2-hr interval, when the spacecraft was about 40,000 km from the lunar surface, the HAARP array illuminated the Moon with a series of 100-ms pulses at 960 kilowatts at a frequency of 8.075 MHz.
During the experiment, the HAARP transmission beam followed the Moon’s apparent motion across the sky in order to keep both WIND and the Moon within the radar beam Thus, the WAVES radio receiver on board WIND detected both the direct HAARP pulses as they passed by the spacecraft on their way to the Moon and the subsequent echo pulses from the lunar surface. 
HAARP-LWA Moon Bounce Experiment
The HF Active Auroral Research Program (HAARP) in Alaska, and the Long Wavelength Array (LWA) in New Mexico, conducted a bistatic low frequency lunar radar experiment in October 2007. A brief description of the experiment and an example of the lunar echo radio waves received may be found in this press release. 
HAARP and LWA are planning an additional lunar echo experiment for 19 and 20 January 2008. Interested radio amateurs and short wave listeners are invited to participate in this experiment by listening for the lunar echoes and submitting reports. The following table shows the planned schedule, where dates and times are in Universal Time (UTC):
HAARP-LWA Experiment Schedule
Date From To Transmitted Frequency
(UTC) UTC Hr:Min) (MHz)
19 January 2008 05:00 06:00 6.7925
06:00 07:00 7.4075
20 January 2008 06:30 07:30 6.7925
07:30 08:30 7.4075
Based on the previous experiment, we believe it should be possible to hear the lunar echoes with a standard communications receiver and an antenna as simple as a 40 meter dipole. If you have a 40 meter beam antenna, point it in the direction of the moon. Other antennas may also yield acceptable results. The format for the transmissions will follow a five second cycle as shown in the following figure. 
The HAARP transmitter will transmit for the first two seconds of the five second cycle. The next three seconds will be quiet to listen for the lunar echo. Then HAARP will transmit again for two seconds, repeating the cycle for the first hour using the first HF frequency. During the second hour, this periodic five second cycle will be repeated but using a different HF frequency as shown in the table above. Transmissions from HAARP during each two-second period, will be carrier only (no modulation). Therefore, listeners should use the CW mode on their receiver to hear HAARP and the lunar echo. We hope to operate this experiment using the frequencies given in the table above. However, depending on frequency occupancy at the time of operation, it may be necessary to adjust the frequency slightly.
Depending on ionospheric conditions, it may or may not be possible to hear the HAARP transmission via skywave. If conditons allow, the HAARP transmission will always be heard during the first two seconds after the five second cycle starts, for example, between 05:00:00 and 05:00:02 and again between 05:00:05 and 05:00:07. The lunar echoes will occur during the three second "quiet" period after HAARP transmits, for example during the interval 05:00:02 until 05:00:05 and again between 05:00:07 until 05:00:10. Depending on a number of factors, you may hear HAARP, the lunar echo, both or neither.
We are interested in receiving signal reports from radio amateurs who may be able to detect, or not detect, the lunar echo or the transmitted skywave pulse from HAARP. It will be helpful if your report includes your call sign and the type and location of your receiving equipment and antennas. 
HALO Solar Radar (HAARP + LOFAR)
LOFAR is the Low Frequency Array for radio astronomy, built by the Netherlands astronomical foundation ASTRON and operated by ASTRON's radio observatory. LOFAR will be the largest connected radio telescope ever built, using a new concept based on a vast array of omni-directional antennas. ... LOFAR was officially opened on 12 June 2010 by Queen Beatrix of the Netherlands. Regular observations started in December 2012. 
The possibility that the ionosphere could be modified by powerful radio waves was first noted by Ginzburg and Gurevich . The early theoretical work concentrated on the heating caused by the powerful radio wave, but later the emphasis gradually changed to plasma instabilities, turbulence, and plasma structuring. The first ionospheric modification facility was built in 1961 near Moscow, Russia, followed by facilities in Colorado, in Puerto Rico, at several additional sites in the former Soviet Union, in Norway, and in Alaska. AIT is currently being studied at research facilities located at middle (Sura, Russia) and high (EISCAT, Norway; HAARP and HIPAS, Alaska, USA) latitudes. In addition, a low latitude facility (Arecibo, Puerto Rico, USA) was active until 1998 and is now being rebuilt. Under construction in Europe is the huge LOFAR (Low Frequency Array), financed by the Dutch government. This 10–240 MHz radio telescope is of a new digital type which ensures maximum flexibility and cost effectiveness, allowing it to become the world’s largest and most efficient instrument for low-frequency radio studies of space. LOFAR is being supplemented by a likewise digital and cost effective infrastructure in Southern Sweden called LOIS (LOFAR Outrigger in Scandinavia). 
Of particular interest is to use LOFAR in combination with so called ionospheric HF interaction facilities. Such facilities are relatively simple to build, using commercially available HF radio transmitters and antennas. Existing systems today include the high-latitude facilities HAARP and HIPAS, Alaska, and EISCAT/Heating (Tromso), Norway, and the mid-latitude Sura facility, Russia.
For nearly 30 years, a low-latitude facility was available at the Arecibo Observatory, Puerto Rico. A few years ago it was destroyed in a hurricane. There are now advanced plans to build a new HF interaction facility at Arecibo. Similar facilities have been proposed for equatorial latitudes both in Africa and in Asia.
We emphasize that a major objective for the future space physics is to further investigate into the possibility that human activities near the Earth may give rise to hitherto unidentified anthropogenic effects. 
These experiments are the tip of a very large iceberg. Even though HAARP's future may be in jeopardy
, new Sky Heaters like the 10 megawatt EISCAT 3D upgrade to the Tromso heater are on the not-to-distant horizon. Welcome to the wild word of science non-fiction. 
The E3D instrument will consist of 5 phased-array antenna fields for transmission (Tx) and reception (Rx) of 233 MHz radio waves. Total transmitted power at the core site will be 10 MW and at least one remote site will have transmission capability of about 1 MW. Digital control of the transmission and low-level digitization of the received signal will allow for instantaneous beam-swinging, and multiple simultaneous transmit and receive beams, without motion of mechanical structures.
The sites will be equipped with smaller outlying antenna arrays that will facilitate aperture synthesis imaging to acquire sub-beam transverse spatial resolution. This will give the E3D radar unmatched power agility and flexibility.
The baseline design listed below suggests a core site that will be located close to the intersection of the Swedish, Norwegian and Finnish borders and four receiving sites located within approximately 50 to 250 km from the core: 
|5 sites (including one with Tx ~10 MW and one with Tx ~1 MW)
multiple outlying sub-arrays at all sites, arbitrary Tx/Rx polarization
|Antenna elements per site
|3 dB receive bandwidth
|Transverse resolution @ 100 km
|Grating lobe free radiation pattern
||out to zenith angles ≥ 45°
||≥ 25 %
||233 MHz (designed for 200 – 240 MHz)
||0.5 µs – CW
|Pulse repetition frequency
||arbitrary phase & amplitude
|operations at zenith ≥ 60°
aperture synthesis imaging
||standard mode: remote
continuous low-duty cycle mode
special high duty cycle modes
automatic response to pre-defined events (switch to special modes)
The E3D concept permits continuous pre-scheduled operations and fast and automatic switching of observation modes. It offers advanced capabilities to study atmospheric phenomena on scales of hundreds of kilometers to hundreds of meters. Atmospheric monitoring at 70-1200 km altitude is only limited by power consumption and data storage. 
- http://www.dtic.mil/dtic/tr/fulltext/u2/a475361.pdf - Naval Research Lab Review 2004
- http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA514972 - High Frequency Radar Astronomy With HAARP
- http://www.nrl.navy.mil/media/news-releases/2008/scientists-detect-lowest-frequency-radar-echo-from-the-moon - Scientists Detect Lowest Frequency Radar Echo From the Moon
- http://web.archive.org/web/20080724034637/http://www.haarp.alaska.edu/haarp/mbcalc.html - Calculation of the Expected Lunar Echo Receive Signal Strength
- http://en.wikipedia.org/wiki/LOFAR - LOFAR on Wikipedia
- http://arxiv-web3.library.cornell.edu/pdf/0707.4506.pdf - Nonlinear physics of the ionosphere and LOIS/LOFAR
- http://www.mso.anu.edu.au/~fbriggs/LOFAR_SciApp_1.0.pdf - LOFAR Scientific Applications, M.P. van Haarlem - 07-03-01
- https://www.eiscat3d.se/status2012 - EISCAT_3D description and status (October 2012)
- https://www.eiscat3d.se/status2012/baseline - EISCAT_3D Baseline design and performance