------------------------------------------------------------------------------------------------------- | Ground System | Explanation | ------------------------------------------------------------------------------------------------------- | 72.2 MHz | A short-wave receiver operating a 72.2 MHz. Audiomodulated signals are | ------------------------------------------------------------------------------------------------------- | ADRES | Canadian computerized ground station. See Gaffen (1993). | ------------------------------------------------------------------------------------------------------- | GMD | Ground Meteorological Direction-finding. Electronic theodolite and radio | ------------------------------------------------------------------------------------------------------- | GMD-1 | First operational version of the GMD system. See U.S. Weather Bureau (1964) | ------------------------------------------------------------------------------------------------------- | GMD-1A | Version of the GMD-1 system. | ------------------------------------------------------------------------------------------------------- | GMD-1B | Version of the GMD-1 system. | ------------------------------------------------------------------------------------------------------- | GMD-4 | Version of the GMD system, presumably with a transponder system, allowing the | ------------------------------------------------------------------------------------------------------- | LORAN | System using Loran navigational aids. | ------------------------------------------------------------------------------------------------------- | OPTICAL THEODOLITE | Visual tracking of balloon using optical theodolite. | ------------------------------------------------------------------------------------------------------- | RADIOTHEODOLITE | Radio tracking of balloon using radiotheodolite. | ------------------------------------------------------------------------------------------------------- | SCR 584 | Signal Corps Radio-direction-finder. Manually operated electronic tracking | ------------------------------------------------------------------------------------------------------- | SCR 658 & METOX | Signal Corps Radio-direction-finder. Manually operated electronic tracking | ------------------------------------------------------------------------------------------------------- | WBRT-57 | U.S. Weather Bureau radiotheodolite, based on the GMD technology. | ------------------------------------------------------------------------------------------------------- | WBRT-60 | U.S. Weather Bureau radiotheodolite. | -------------------------------------------------------------------------------------------------------