The Effect of Chaotic Vibrations on Antenna Characteristics

The radio signal transmitted from a vibrating antenna is modulated producing spectral content that can interfere with a nearby receiver. The additional spectral content is centered at the transmitted RF signal, and with chaotic vibrations, the spectrum has significant content beyond the fundamental frequency of vibration. Thus, the effect of vibration on co-site interference is much greater than expected. A controlled experiment using a monopole antenna driven at 900 MHz and vibrating at 150 Hz has significant RF spectral content extending to 5 kHz.