|C-Band - WRC 2015|
Why the WRC Spectrum Fight Matters to You – And What You Can Do About It
You probably know that the World Radiocommunications Congress will take up the issue of opening parts of C-Band for use by the mobile industry at its meeting in November 2015. Many teleport operators tell us that they think this is not their problem – that the satellite operators will fight the battle or that an attack on C-Band won’t succeed. The truth is, we all need to help. Mobile technology companies are funding an aggressive fight, and they have already convinced the European Union to go on record in support of opening up the band. The Satellite Spectrum Initiative – a collaboration of many organizations including WTA – is working hard but does not have the same resources.
So, you can help today by contacting your regulatory authority and stating your opposition to allowing mobile carriers to use C-Band. The plain fact is that C-Band transmitters on the ground – from base stations to individual mobile phones – will drown out any earth station within range. So if your business uses C-Band, the time to register your opinion is now!
Why Do Satellites Need Their Own Radio Bands?
The hundreds of communications satellites in orbit today circle the earth at an altitude of 22,000 miles or 36,000 kilometers. That’s 1-1/2 times the distance you would travel on an around-the-world trip. It’s a long way for anything to go, including radio waves.
Radio waves start out the journey strong, but by the time they reach their destination, a lot of their energy has been lost along the way. It is like the way the sound of your voice fades with distance, no matter how loudly you shout.
Radio signals beamed up into space reach satellites in pretty faint condition, but there is not much else going on in high earth orbit, and the radio receivers on the satellite can usually pick them up.
The job of a communications satellite is to receive a signal and send an exact duplicate of it back to earth. As it crosses space and enters our atmosphere, this signal too loses power. By the time it reaches the ground, it is very faint, and it takes specialized satellite antennas to pick it up. But it only works if there is no stronger signal in the same frequency range nearby.
In the Interference Battle, Satellite Loses
Let’s say you have a radio on the ground and start transmitting in the same frequency band as a satellite antenna in the neighborhood. What happens? Your signal completely overwhelms the faint signal from space, and the satellite connection is lost.
The neighborhood in this case can be pretty big. It may be thousands of feet or meters; it can also be dozens of miles or kilometers.
That’s why satellites were given their own frequency bands to begin with. And it is why the satellite industry is resisting efforts to open up those frequency bands for other uses. The mobile industry would like to start sharing satellite bands to help meet the needs of their customers for mobile voice and data.
Sharing is nice, and we all like our mobile phones. But in this case, once a satellite band is shared with users on the ground, it is “game over” for satellite.
Mobile phones and base stations would become loudspeakers that throw every nearby satellite antenna off the air. And with it may go television programs, Internet access, retail store sales data, weather data, school lessons and lifeline telephone service for people in need – all of the essential communications that make the world a better place.
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