Testing for FM-radio interference in motor vehicles

A comparison has been carried out between two tests for predicting the effect of motor-vehicle RF emissions upon onboard FM receivers. The tests are the Society of Automotive Engineers J551/4, an RF peak amplitude test, and the State of Texas Tex-899-B, an FM receiver SMAD test. Tex-899-B would seem a natural choice because it employs an FM receiver like that used in the vehicle, but we have found that, by making judicious adjustments in the J551/4 limits, J551/4 can also be used, and this may afford an important testing option.