June 14, 2005
Add the National Academy of Sciences to those worried about the use of cell phones on airplanes. The Academy says the devices could interfere with radio astronomy.
However, the academy's National Research Council Committee on Radio Frequencies (CORF) said it could support the use of so-called "picocells" on aircraft -- miniature repeating stations that would collect all of the individual calls being made by passengers and beam them to the ground for further handling.
The frequencies at which radio astronomers observe are dictated by the laws of nature, the scientists noted. Furthermore, the emissions that radio astronomers receive at these frequencies are extremely weak - a typical radio telescope receives only about one-trillionth of a watt from even the strongest cosmic source.
Because radio astronomy receivers are designed to pick up such remarkably weak signals, such facilities are particularly vulnerable to interference from spurious and out-of-band emissions from licensed and unlicensed users of neighboring bands, and those that produce harmonic emissions that fall into the radio telescope bands.
The Federal Communications Commission (FCC) and the Federal Aviation Administration (FAA) have been considering various options that would allow the use of cell phones in flight and there have been several successful demonstrations using picocells.
Wireless Internet service is also in the works but does not pose an interference problem since, like the picocell protocol, transmissions will be collected and handled in the same way as the seat-back phones still in use on some airlines.
"CORF takes no position as to whether the Commission should authorize the airborne use of cellular telephones, but CORF strongly supports the proposal to permit airborne use only if the handsets are controlled by an airborne picocell so that the likelihood and severity of interference to RAS facilities is minimized," the Research Council said in a statement.
CORF also said it supported modifying the required emission mask for cellular telephone hand units, which could reduce the possibility and severity of interference.
