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Radio Astronomy (25.55 - 25.67 MHz)
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The band 25.55 - 25.67 MHz is allocated to the radio astronomy service. It is allocated on a primary exclusive basis in the U.S. and in all three ITU regions.
One radio astronomy facility that is being designed to make use of frequencies in this range is the Long Wavelength Array (LWA), which is co-located with the Very Large Array near Socorro, NM. The LWA design range is 10-88 MHz, with the main science goals and observing targets being relativistic particles in space (including supernova remnants, radio galaxies, and cosmic rays); cosmic evolution and the high-redshift universe; plasma astrophysics and space science; and transient cosmic radio sources.
Two major factors make radio astronomy at this low frequency very difficult. First, under normal conditions, the ionosphere heavily absorbs radio signals in this frequency range. Radio signals that are not absorbed will suffer strong and time-variable distortions due to density fluctations and motion of ionized material in the ionosphere.
Second, due to long-distance propagation of terrestrial radio signals in this range, radio frequency interference is a substantial problem, even for radio telescopes that are located at very remote sites. Within all three ITU regions, the band is allocated on an exclusive basis to radio astronomy, but individual countries can and do make allocations that do not conform with the ITU allocations.
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Frequency Bands |
| Band | Use | Service11 | Table |
| 25550 - 25670 kHz | Radio Astronomy (25.55 - 25.67 MHz) | Radio Astronomy | - |
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