frequencies for IRI operation. The HAARP makes current and historic digisonde information available online. An induction magnetometer, provided by the University of Tokyo, that measures the changing geomagnetic field in the Ultra Low Frequency (ULF) range of 0–5 Hz. The facility is powered by a set of five 2500 kilowatt generators being driven by EMD 20-645-E4 diesel locomotive engines. Site The project site () is north of Gakona, Alaska just west of Wrangell-Saint Elias National Park. An environmental impact statement led to permission for an array of up to 180 antennas to be erected. HAARP was constructed at the previous site of an over-the-horizon radar (OTH) installation. A large structure, built to house the OTH now houses the HAARP control room, kitchen and offices. Several other small structures house various instruments. The HAARP site was constructed in three distinct phases: The Developmental Prototype (DP) had 18 antenna elements, organized in three columns by six rows. It was fed with a total of 360 kilowatts (kW) combined transmitter output power. The DP transmitted just enough power for the most basic of ionospheric testing. The Filled Developmental Prototype (FDP) had 48 antenna units arrayed in six columns by eight rows, with 960 kW of transmitter power. It was fairly comparable to other ionospheric heating facilities. This was used for a number of successful scientific experiments and ionospheric exploration campaigns over the years. The Final IRI (FIRI) is the final build of the IRI. It has 180 antenna units, organized in 15 columns by 12 rows, yielding a theoretical maximum gain of 31 dB. A total of 3.6 MW of transmitter power will feed it, but the power is focused in the upward direction by the geometry of the large phased array of antennas which allow the antennas to work together in controlling the direction. , all the antennas were in place, the final phase was completed and the antenna array was undergoing testing aimed at fine-tuning its performance to comply with safety requirements required by regulatory agencies. The facility officially began full operations in its final status of 3.6MW transmitter power in the summer of 2007, yielding a maximum effective radiated power (ERP) of 5.1gigawatts or 97.1dBW. However, the site typically operates at a fraction of that power due to the lower antenna gain exhibited at frequencies used in standard operation. Related facilities In the United States, there have been two related