Super-Sized M2 (9.5"x9.0") 2-Bay Bowtie antennas with various alternative reflectors analyzed using 4nec2. Reflector Separation for all simulations is 4.5", measured from centerline of Bowties. No SWR reoptimization (e.g. readjust Feedline Separation) has been performed, so there may be room for minor improvements.
The single Vertical or Horizontal BBQ Grates were TOO SMALL, giving away several dB of Gain, but might still be useful. A pair of BBQ Grates (22"x24") provided slightly MORE gain than a Screen Reflector (2"x4" Grid), although SWR increased a bit. An 18-in diameter "Pizza Pan" Reflector fell in-between the one and two BBQ Grate alternatives.
Note that a somewhat larger 2-Bay would have improved Raw Gain and SWR performance on the lower frequencies with minor or no impact on higher frequencies.
Screen reflector (24"x24") using 2"H x 4"W grid was compared to various alternatives based on one or two 11"x25" BBQ Grates (Lowes #201757):
a) M2 (9.5"x9.0") 2-Bay, 24"x24" Grid Reflector: UHF Raw Gain = 9.9 to 13.2 dBi with SWR under 2.4. Hi-VHF (Ch7-13) Raw Gain = 6.9 to 3.1 dBi but SWR is EXCESSIVE.
b) M2 (9.5"x9.0") 2-Bay, One Vert. Polarized 11"x25" BBQ Grate: UHF Raw Gain = 6.8 to 9.8 dBi with SWR under 2.7 thru Ch51.
c) M2 (9.5"x9.0") 2-Bay, Two Vert. Polarized 11"x25" BBQ Grates: UHF Raw Gain = 7.3 to 9.3 dBi with SWR under 2.3 thru Ch51.
d) M2 (9.5"x9.0") 2-Bay, One Horiz. Polarized 11"x25" BBQ Grate: UHF Raw Gain = 8.7 to 11.3 dBi with SWR under 3.0.
e) M2 (9.5"x9.0") 2-Bay, Two Horiz. Polarized 11"x25" BBQ Grates: UHF Raw Gain = 10.6 to 13.3 dBi with SWR under 3.0.
f) M2 (9.5"x9.0") 2-Bay, Two BENT Horiz. Polarized 11"x25" BBQ Grates: UHF Raw Gain = 10.6 to 13.3 dBi with SWR under 3.1. Hi-VHF (Ch7-13) Raw Gain = 3.7 to 4.5 dBi but SWR is EXCESSIVE.
g) M2 (9.5"x9.0") 2-Bay, 18" Pizza Pan Reflector: UHF Raw Gain = 8.9 to 9.4 dBi with SWR under 2.5.
Date(s): 31Jan2011. Album by holl_ands. 1 - 48 of 48 Total. 4467 Visits.
enlarge 152KB, 1152x717 7 M2 (9.5"x9.0") 2-Bay, 24"x24" Grid Reflector Hi-VHF (Ch7-13) Raw Gain = 6.9 to 3.1 dBi HIGHER towards the REAR on Low Channels
enlarge 128KB, 1024x686 8 M2 (9.5"x9.0") 2-Bay, 24"x24" Grid Reflector Hi-VHF (Ch7-13) Raw Gain = -2.5 to 7.5 dBi Higher FORWARD only on Highest Channels
enlarge 245KB, 880x1024 34 M2 (9.5"x9.0") 2-Bay, Two BENT Vert. 11"x25" BBQ Grates 3D View
enlarge 300KB, 1024x873 35 M2 (9.5"x9.0") 2-Bay, Two BENT Vert. 11"x25" BBQ Grates Front View [1 small box = 0.5 inch]
enlarge 41KB, 791x1024 36 M2 (9.5"x9.0") 2-Bay, Two BENT Vert. 11"x25" BBQ Grates 4nec2 File
enlarge 181KB, 1152x717 37 M2 (9.5"x9.0") 2-Bay, Two BENT Vert. 11"x25" BBQ Grates UHF Raw Gain = 10.6 to 13.3 dBi
enlarge 169KB, 1152x717 38 M2 (9.5"x9.0") 2-Bay, Two BENT Vert. 11"x25" BBQ Grates UHF SWR (300-ohm) under 3.1
enlarge 168KB, 1152x717 39 M2 (9.5"x9.0") 2-Bay, Two BENT Vert. 11"x25" BBQ Grates UHF Impedance
enlarge 150KB, 1152x717 40 M2 (9.5"x9.0") 2-Bay, Two BENT Vert. 11"x25" BBQ Grates Hi-VHF (Ch7-13) Raw Gain = 3.7 to 4.5 dBi Gain is LARGER to the REAR (Azimuth = 270-deg)
enlarge 189KB, 1152x717 41 M2 (9.5"x9.0") 2-Bay, Two BENT Vert. 11"x25" BBQ Grates Hi-VHF (Ch7-13) SWR (300-ohm) is EXCESSIVE
enlarge 160KB, 1152x717 42 M2 (9.5"x9.0") 2-Bay, Two BENT Vert. 11"x25" BBQ Grates Hi-VHF (Ch7-13) Impedance
enlarge 175KB, 1024x955 43 M2 (9.5"x9.0") 2-Bay, 18" Pizza Pan Reflector 3D View
enlarge 266KB, 1024x790 44 M2 (9.5"x9.0") 2-Bay, 18" Pizza Pan Reflector Front View [1 small box = 0.5 inch]
