IF you erect new additional antennas in the near field, you will find they change existing antennas swr/resonance. Especially on 160/80. antennas interact dramatically. Ive noticed this with my AD 160/80/40M Shorty antenna ( 100 ft total length inverted v and any other 40/80/160m antennas Ive put up within 100 ft. Everything affects everything at those frequencies.