ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, Nevada / This paper will present techniques for accurately measuring the power flux density (PFD) of interfering signals at telemetry receiving stations. The solar power flux density is measured daily by radio astronomers and will be used as a calibration signal. The electromagnetic spectrum is being used more intensely as time marches on so being familiar with interference measurement techniques is becoming more important because more interfering signals are present.