CM4251 Parabolic Reflector with 4-Wires added to Reflector (FBmod) and 8-Element LPDA (Log Periodic Dipole Array) Feed analyzed using 4nec2.
CM4251 2-Bay Feed is replaced by 8-Element LPDA, see fol. analysis, which was fabricated by oldsparks: http://www.qsl.net/va3rr/hdtv/HDTV.htm GHZ24 offset & reversed the LPDA for insertion into a Parabolic Reflector 4nec2 File: http://ghz24.freeshell.org/antenna/models/newermodels/parabolas/feeds/lpda8.nec
Note glitches near 698 MHz for Raw Gain, F/B and F/R Ratios. Although probably not large enough to cause problems, this can be cured by adding a shorting stub.
Date(s): 24 May 2013. Album by holl_ands. 1 - 9 of 9 Total. 4941 Visits.
enlarge 233KB, 1024x696 1 CM-4251 Parabolic+FBmod+8-El LPDA Comparison Chart: Various x = Separation from Parabolic Reflector to Smallest LPDA Element
enlarge 149KB, 789x1024 2 CM-4251 Parabolic+FBmod+8-El LPDA 3D View
enlarge 248KB, 991x1024 3 CM-4251 Parabolic+FBmod+8-El LPDA Front View [1 large box = 12.5 inches]
enlarge 170KB, 693x1024 4 CM-4251 Parabolic+FBmod+8-El LPDA Top View [1 large box = 12.5 inches]
enlarge 157KB, 703x1024 5 CM-4251 Parabolic+FBmod+8-El LPDA Side View [1 large box = 12.5 inches]