Near Vertical Incident Scattering Antenna

11/17/98


Table of Contents

Why use an NVIS antenna?

Limitations

NVIS Antenna Dimensions

Parts List

Construction of NVIS Antenna

Author: Dr. Carl O. Jelinek N6VNG (SK)

  • Usable on all HF ham bands.
  • To work the Skip Zone {out to about 1000 miles}.
  • Areas behind obstructions and in dense foliage.
  • To hear the near in stations just beyond ground wave range.
  • Great for Field Day and contesting as a “Gap Filler” antenna.
  • Easy antenna for HF mountain topping and camping trips to get RF out of deep canyons.

  • Must work frequencies below the Maximum Usable Frequency (MUF).
  • This is not a DX antenna.
  • Needs to use an antenna tuner for good match.
  • Power Limited to about 200 Watts.
  • Beverage Mode Losses limit achievable gain.

    NVIS Antenna Dimensions

  • Drill PVC Cap to accept SO-239 and 4 screws and nuts
  • Mount SO-239 to PVC Cap with screw heads down
  • Cut off the head of a brass screw
  • Solder a brass screw to center post of SO-239
  • Cut antenna wires to length plus a little
  • Fit one end of each wire with solder lugs
  • Fit the other with the egg insulators
  • Install wires to SO-239 using brass nuts and washers {as shown in the figure}
  • Erect antenna (2 men ~ 5 minutes)
  • Tune antenna match for minimum VSWR (also could adjust mast height and wire lengths)