X band 10.15 to 10.7 GHz segment is used for terrestrial broadband in many countries, such as Brazil, Mexico, Saudi Arabia, Denmark, Ukraine, Spain and Ireland. Alvarion, CBNL, CableFree and Ogier make systems for this, though each has a proprietary airlink. The Ogier system is a full duplex Transverter used for DOCSIS over microwave. The home / Business CPE has a single coaxial cable with a power adapter connecting to an ordinary cable modem. The local oscillator is usually 9750 MHz, the same as for Ku band satellite TV LNB. Two way applications such as broadband typically use a 350 MHz TX offset.
Space communications
Portions of the X band are assigned by the International Telecommunications Union exclusively for deep space telecommunications. The primary user of this allocation is the American NASA Deep Space Network. DSN facilities are in Goldstone, California, near Canberra, Australia, and near Madrid, Spain. These three stations, located approximately 120 degrees apart in longitude, provide continual communications from the Earth to almost any point in the Solar System independent of Earth rotation. DSN stations are capable of using the older and lower S band deep-space radio communications allocations, and some higher frequencies on a more-or-less experimental basis, such as in the K band. Notable deep space probe programs that have employed X band communications include the VikingMars landers; the Voyager missions to Jupiter, Saturn, and beyond; the Galileo Jupiter orbiter; the New Horizons mission to Pluto and the Kuiper belt, the Curiosity rover and the Cassini-Huygens Saturn orbiter. The new European double Mars Mission ExoMars will also use X band communication, on the instrument LaRa, to study the internal structure of Mars, and to make precise measurements of the rotation and orientation of Mars by monitoring two-way Doppler frequency shifts between the surface platform and Earth. It will also detect variations in angular momentum due to the redistribution of masses, such as the migration of ice from the polar caps to the atmosphere. An important use of the X band communications came with the two Viking program landers. When the planet Mars was passing near or behind the Sun, as seen from the Earth, a Viking lander would transmit two simultaneous continuous-wave carriers, one in the S band and one in the X band in the direction of the Earth, where they were picked up by DSN ground stations. By making simultaneous measurements at the two different frequencies, the resulting data enabled theoretical physicists to verify the mathematical predictions of Albert Einstein's General Theory of Relativity. These results are some of the best confirmations of the General Theory of Relativity.
s often use 10.525 GHz. 10.4 GHz is proposed for traffic light crossing detectors. Comreg in Ireland has allocated 10.450 GHz for Traffic Sensors as SRD. Many electron paramagnetic resonance spectrometers operate near 9.8 GHz. Particle accelerators may be powered by X-band RF sources. The frequencies are then standardized at 11.9942 GHz or 11.424 GHz, which is the second harmonic of C-band and fourth harmonic of S-band. The European X-band frequency is used for the Compact Linear Collider.
