Fig. 1. Diagram of vehicle engine ignition system

Fig. 2. Noise power ratio of vehicle engine ignition on and off

Fig. 3. Time domain waveforms and spectrums of three rectangular pulse signals

Fig. 4. EM model of the effect of car ignition on the monopole antenna

Fig. 5. Transmission loss of the car ignition-equivalent antenna to 10 m monopole antenna

Fig. 6. EM model of 2-car ignition-equivalent antenna and the transmission loss

Fig. 7. Input impedance and reactance of the truck ignition-equivalent antenna

Fig. 8. Radiation pattern in x-y plane of the truck ignition-equivalent antenna

Fig. 9. Transmission loss of the truck ignition-equivalent antenna to 10 m monopole antenna（in 50 m）

Fig. 10. Man-made noise at typical frequency

Fig. 11. Comparison of the spectrums with vehicle ignition at the location D and E

Fig. 12. Comparison of the noise floor after signal smoothing