Frequency Issues
Home Up The Radiosonde Uses of the  Data Maintenance Issues Frequency Issues


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

freq1680.gif (6626 bytes)

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

freq403.gif (5232 bytes)
Links to other sites related to radio-frequency issues:


Back Home Up

This site is maintained by the:

   Programs and Plans Division
   Office of Science and Technology
   National Weather Service

Date Last Modified: December 6, 2001