UHF CM4248 15-Element Folded Dipole (FD) Yagi with 14 Reflector Rod (RR) Corner Reflector analyzed using 4nec2 from a file posted by user <300ohm>, which was based on Measurements by Ken Nist, posted in an EZNEC file on http://www.hdtvprimer.com/ANTENNAS/comparing.html. CM3023 is reportedly similar (if not the SAME) as CM4248.
Several Modifications to the Corner Reflector were then analyzed, including adding 12 Reflector Rods half-way between the existing 14 RRs compared to a pair of Screen Reflectors with the same as well as larger widths.
Three versions are shown here:
====================================== a) CM4248 15El FD-Yagi (Original) with 14 Reflector Rods in Corner Reflector:
UHF Raw Gain = 12.2 to 14.5 dBi, F/B & F/R Ratio = 18 dB and SWR (300-ohms) Under 2.6.
====================================== b) CM4248 15El FD-Yagi - Plus 12 RR's Half-Way Between 14 RR's in Corner Reflector:
UHF Raw Gain = 12.5 to 15.0 dBi, F/B & F/R Min = 22 dB and SWR (300-ohms) Under 2.9.
===================================== c) CM4248 15El FD-Yagi - Plus Corner Reflector using a Pair of 23x33-in Screen Reflectors (1x1-in Grid):
UHF Raw Gain = 12.2 to 15.0 dBi, F/B & F/R Ratio Min = 20.0 dB and SWR (300-ohms) Under 2.8.
===================================== All THREE versions are plotted in the Chart, showing only a MINOR (under 0.5 dB) improvement. The second and third alternatives are essentially the SAME above 518 MHz, but the Reflector Screen version has less Gain on lower Frequencies. Wider variations for each version did NOT provide any improvement. And a variation of the second version with 3 RR's filling in the Apex also did NOT help.
Date(s): 13 Jun 2015. Album by holl_ands. 1 - 28 of 28 Total. 5213 Visits.
enlarge 97KB, 1024x799 1 CM4248 15El FD-Yagi (Original) with 14 Reflector Rods in Corner Reflector 3D View
enlarge 265KB, 1014x1024 2 CM4248 15El FD-Yagi (Original) with 14 Reflector Rods in Corner Reflector Front View [1 large square = 5 inches]
enlarge 162KB, 1024x686 3 CM4248 15El FD-Yagi (Original) with 14 Reflector Rods in Corner Reflector Side View [1 large square = 12.5 inches]
enlarge 146KB, 1024x741 4 CM4248 15El FD-Yagi (Original) with 14 Reflector Rods in Corner Reflector UHF Raw Gain = 12.2 to 14.5 dBi UHF F/B & F/R Ratio = 18 dB
enlarge 180KB, 1024x741 5 CM4248 15El FD-Yagi (Original) with 14 Reflector Rods in Corner Reflector UHF SWR (300-ohms) Under 2.6
enlarge 220KB, 1024x741 6 CM4248 15El FD-Yagi (Original) with 14 Reflector Rods in Corner Reflector UHF Impedance
enlarge 304KB, 1024x1024 7 CM4248 15El FD-Yagi (Original) with 14 Reflector Rods in Corner Reflector Azimuthal Pattern at 470 MHz
enlarge 303KB, 1024x1024 8 CM4248 15El FD-Yagi (Original) with 14 Reflector Rods in Corner Reflector Azimuthal Pattern at 530 MHz
enlarge 304KB, 1024x1024 9 CM4248 15El FD-Yagi (Original) with 14 Reflector Rods in Corner Reflector Azimuthal Pattern at 590 MHz
enlarge 302KB, 1024x1024 10 CM4248 15El FD-Yagi (Original) with 14 Reflector Rods in Corner Reflector Azimuthal Pattern at 650 MHz
enlarge 304KB, 1024x1024 11 CM4248 15El FD-Yagi (Original) with 14 Reflector Rods in Corner Reflector Azimuthal Pattern at 698 MHz
enlarge 307KB, 1024x1024 12 CM4248 15El FD-Yagi (Original) with 14 Reflector Rods in Corner Reflector Azimuthal Pattern at 758 MHz
enlarge 310KB, 1024x1024 13 CM4248 15El FD-Yagi (Original) with 14 Reflector Rods in Corner Reflector Azimuthal Pattern at 806 MHz
enlarge 32KB, 791x1024 14 CM4248 15El FD-Yagi (Original) with 14 Reflector Rods in Corner Reflector 4nec2 File includes Summary of Dimensions
enlarge 161KB, 1024x691 15 CM4248 15El FD-Yagi (Original) with 14 Reflector Rods in Corner Reflector Top View [1 large square = 12.5 inches]
enlarge 136KB, 1024x833 16 CM4248 15El FD-Yagi - Plus 12 RR's Half-Way Between 14 RR's in Corner Reflector 3D View
enlarge 284KB, 991x1024 17 CM4248 15El FD-Yagi - Plus 12 RR's Half-Way Between 14 RR's in Corner Reflector Front View [1 large square = 5 inches]
enlarge 170KB, 1024x716 18 CM4248 15El FD-Yagi - Plus 12 RR's Half-Way Between 14 RR's in Corner Reflector Side View [1 large square = 12.5 inches]
enlarge 172KB, 1024x741 19 CM4248 15El FD-Yagi - Plus 12 RR's Half-Way Between 14 RR's in Corner Reflector UHF Raw Gain = 12.5 to 15.0 dBi UHF F/B & F/R Min = 22 dB
enlarge 190KB, 1024x741 20 CM4248 15El FD-Yagi - Plus 12 RR's Half-Way Between 14 RR's in Corner Reflector UHF SWR (300-ohms) Under 2.9
enlarge 166KB, 1024x701 21 CM4248 15El FD-Yagi - Plus 12 RR's Half-Way Between 14 RR's in Corner Reflector Top View [1 large square = 12.5 inches]
enlarge 219KB, 1024x881 22 CM4248 15El FD-Yagi - Plus Corner Reflector using a Pair of 23x33-in Screen Reflectors (1x1-in Grid) 3D View [SAME SIZE as 14RR's in Original]
enlarge 386KB, 1007x1024 23 CM4248 15El FD-Yagi - Plus Corner Reflector using a Pair of 23x33-in Screen Reflectors (1x1-in Grid) Front View [1 large square = 5 inches]
enlarge 166KB, 1024x702 24 CM4248 15El FD-Yagi - Plus Corner Reflector using a Pair of 23x33-in Screen Reflectors (1x1-in Grid) Side View [1 large square = 12.5 inches]
enlarge 170KB, 1024x741 25 CM4248 15El FD-Yagi - Plus Corner Reflector using a Pair of 23x33-in Screen Reflectors (1x1-in Grid) UHF Raw Gain = 12.2 to 15.0 dBi UHF F/B & F/R Ratio Min = 20.0 dB
enlarge 184KB, 1024x741 26 CM4248 15El FD-Yagi - Plus Corner Reflector using a Pair of 23x33-in Screen Reflectors (1x1-in Grid) UHF SWR (300-ohms) Under 2.8
enlarge 171KB, 1024x690 27 CM4248 15El FD-Yagi - Plus Corner Reflector using a Pair of 23x33-in Screen Reflectors (1x1-in Grid) Top View [1 large square = 12.5 inches]
enlarge 202KB, 1024x696 28 CM4248 15El FD-Yagi - Original Corner Reflector compared to Various Alternatives
