AGENDA ITEM 1.15: 3-50 MHZ, OCEANOGRAPHIC RADAR

To consider possible allocations in the range 3-50 MHz to the radiolocation service for oceanographic radar applications, taking into account the results of ITU R studies, in accordance with Resolution 612 (WRC 07).

Earth Exploration-Satellite Service

Agenda Item 1.15 seeks to provide a formal allocation for oceanographic radars which have operated on an experimental basis between 3 and 50 MHz in the past. A number of systems are deployed along the U.S. coast that support oceanographic observations of winds and currents.1 The frequencies and power levels of these wave radar (WERA) systems vary (see Table 2.9). Bandwidths of WERA systems depend on resolution and typically are 50 kHz or 125 kHz, though 500 kHz is desired for high resolution applications.2 The systems could potentially be used for tsunami warnings and sea ice motion. They are also used for monitoring oil spills, ship movements and search and rescue applications and have become essential for both safety and meteorological applications. A formal allocation is sought to continue to support these uses.

TABLE 2.9 Example Systems with Center Frequencies and, where available, Transmit Power Levels


WERA System Location Frequency and Transmit Power Levels (where applicable)

OSCR U.S. 24.5 MHz
NASA U.S. 50.0 MHz
NiCT Japan 9.25 MHz
WERA Germany 29.85 MHz, 27.65 MHz, 16.045 MHz, 12.50 MHz (30 W)
WERA Florida 12 MHz 16 MHz (30 W)
WERA South Carolina 8.3 MHz (30 W)

Conclusion: Oceanographic radars operating in 3-50 MHz do not adversely affect any other known EESS bands and are thus not of concern for EESS(passive), so long as out-of-band RFI is maintained at levels compatible with Recommendation ITU-R RS.1029.

Radio Astronomy Service

The primary concern for Radio Astronomy is the Radio Astronomy Service (RAS) bands in the 3-50 MHz range (which include 13.36-13.41, 25.56-25.67 and 37.50-38.25 MHz) should be protected from unwanted emissions due to new allocations.

Use of 10-50 MHz is important to current and future radio astronomy. Features essential to understanding the earliest cosmic structures (redshifted hydrogen from the “Dark Ages” before the first generation of quasars) are expected to appear in the lowest frequencies accessible through the ionosphere. Signals in this frequency range propagate on continental to global scales due to ionospheric refraction and other mechanisms. Every effort should be made to ensure that the oceanographic radars do not impact the radio telescopes operating between 3-50 MHz.

Scientific frontiers in this frequency range include: (1) The periodic or transient universe such as the emission from extra-solar planets, gamma-ray bursts, ultra-high energy cosmic rays, and new sources

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1 See http://sampit.geol.sc.edu/radar.html.

2 See http://ifmaxp1.ifm.uni-hamburg.de/WERA_Guide/WERA_Guide.shtml.



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