| Issues in the
use of Radio-Frequency Spectrum |
|
| The current generation of radiosondes use a
single-stage transmitter design demanding large portions of the frequency
spectrum, namely 1670 through 1690 MHz. This design uses a greater portion of
the frequency spectrum compared to more expensive components capable of
maintaining a more stable transmission frequency. The current ground receiving
equipment receives signals across the same large range, matching the
radiosondes. As a result of the Omnibus Budget Reconciliation Act of 1993, the
Government has reallocated 5 MHz (1670-1675 MHz) to the private sector as of
January 1, 1999. The current ground systems will be very susceptible to
interference from new transmitters operating in this broad frequency band. This
would result in lost data during portions of the radiosonde flights and cause
an inability to operate the system at some locations. Furthermore, the
radiosonde transmitters will be required to be tuned to a higher frequency to
prevent interference with new receivers operating in the 1670-1675 MHz
frequency band. Use of higher frequencies in the approved range for radiosonde
operations will increase the existing interference between radiosondes and data
transmissions from meteorological satellites to various users across the
country. |
|
Meteorological Aids Allocation: 1670 to 1710 MHz |
 |
|
The other frequency spectrum band allocated to
meteorological aids is the 400.15 to 406 MHz band. The NWS operates
several radiosonde systems in this band, which is generally more crowded and
has more interference than the 1680 MHz band. Most radiosonde systems
sold to private industry, local governments, and educational institutions in
the United States utilize this band. |
|
Meteorological Aids Allocation: 400.15 to 406 MHz |
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| Links to other sites related to radio-frequency
issues:
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