RFI ANALYSIS APPLIED TO THE TDRSS SYSTEM

• Main Author: Jenny, J.A.
• Other Authors: ESL Incorporated
• Language: en_US
• Published: International Foundation for Telemetering 1973
• Online Access: http://hdl.handle.net/10150/604598; http://arizona.openrepository.com/arizona/handle/10150/604598

International Telemetering Conference Proceedings / October 09-11, 1973 / Sheraton Inn Northeast, Washington, D.C. === The effect of radio frequency interference (RFI) on the proposed Tracking and Data Relay Satellite System (TDRSS) was assessed. The method of assessing RFI was to create a discrete emitter listing containing all the required parameters of transmitters in the applicable VHF and UHF frequency bands. The transmitter and spacecraft receiver characteristics were used to calculate the RFI contribution due to each emitter. The individual contributions were summed to obtain the total impact in the operational bandwidth. Using an as yet incomplete enitter base, we have concluded that the 136-137 MHz band should be used by TDRS rather than the whole 136-138 MHz band because of the higher interference levels in the 137-138 MHz band. Even when restricting the link to 136 to 137 MHz, the existing link design is marginal and it is recommended that interference reduction units, such as the Adaptive Digital Filter, be incorporated in the TDRS ground station. RFI is less of a problem in the 400.5 to 401.5 MHz band and can probably be handled by restricting command transmissions to low RFI areas or if that is not acceptable, by using simple automatic notch filters to notch out the few interferers present.