Unclassified-the Naval Postgraduate School GBS testbed

A downlink testbed for the Global Broadcast System (GBS) has been installed at the Naval Postgraduate School in the NPS Systems Technology Laboratory (STL). The purpose of the testbed is to conduct research on the link characteristics of GBS broadcasts that can be received in Monterey. The GBS Conus transmission is a Ku-band signal from the uplink testbed at the Pentagon via the medium power SBS-6 satellite located at 79 degrees West. In addition, the testbed receives and analyzes commercial Direct TV and Dish Net Ku-band broadcasts. The testbed has been instrumented to monitor carrier power levels and background noise levels for each of the active transponders. Statistical analysis of this data is planned to develop distributions of C/No and Eb/No for the different transmissions. Values are compared with computed link budgets. Correlation with local meteorological measurements is planned. Bit error rate testing is included to evaluate receiver/decoder losses and to validate effects of variable data rate