Wide - Band Test Antennas

As part of an indoor mutt/path measurement system, discone antennas featuring simple N~onnector feed systems have bHn designed for the 1.0 to 2.0 GHz band. Extensive experimentation reveals that excellent performance (VSWR < 15:1 across the band) can be obtained with a simple "snap-on" feed/mount method, and that VSWR is most sensitive to the diameter of the disc feed conductor. Per· formance data from over 70 discone antennas having a variety of flare angles, disc-to-cone spacings and feed conductor diameters are summarized here. Data shows that for N-conn&Ctor mounts, best flare angles range between 45° and 75°, and that the disc feed conductor should be 0.33 times the diameter of the cone top. The empirical data reveals that the antennas may be tuned for even better match by using a simple clamp nut tuning scheme. Design equations, which differ from Nail's (2) because of the large mini· mum cone diameter; are presented.