• Public Gallery  • Help
		• Join Now!  • Log In  • Feature Tour

holl_ands | Home > Parabolic Antennas > Browse:Comparison Charts - ParabolicsCM4251 7-ft Parabolic + 2-Bay Refl FeedCM4251 Parabolic + 4-Wire FBmodCM-4251 Parabolic+FBmod - Bigger 2-BayCM4251 Parabolic+FBmod - Opt. 2-Bay 9-RRCM-4251 Parabolic+FBmod+8-El LPDACM-4251 Parabolic+FBmod+9-El LPDAUHF 2-m Parabolic + 8-El LPDA Feed
CM-4251 Parabolic+FBmod+9-El LPDA CM4251 Parabolic Reflector with 4-Wires added to Reflector (FBmod) and 9-Element LPDA (Log Periodic Dipole Array) Feed analyzed using 4nec2. CM4251 2-Bay Feed is replaced by 9-Element LPDA, see fol. analysis: http://imageevent.com/holl_ands/zigzaglpa/uhflpda/uhf9ellpcad34 Note uniformity of Raw Gain with small loss at higher freqs, low SWR and excellent F/B and F/R Ratios across entire UHF Band. When 9-El LPDA is used with CM4251, the small loss in Gain with frequency stayed about the same with a small improvement in SWR.   However LPDA's excellent F/B & F/R Ratios were reduced across all freq, esp. on lower channels. Hence this reduction is attributed to inadequacies in the CM4251's Reflector. Date(s): 21 Mar 2013. Album by holl_ands. 1 - 15 of 15 Total. 5205 Visits.
enlarge 138KB, 772x1024 1 CM-4251 Parabolic+FBmod+9-El LPDA 3D View enlarge 242KB, 987x1024 2 CM-4251 Parabolic+FBmod+9-El LPDA Front View [1 large square = 12.5 inches] enlarge 151KB, 618x1024 3 CM-4251 Parabolic+FBmod+9-El LPDA Top View [1 large square = 12.5 inches] enlarge 193KB, 1152x678 4 CM-4251 Parabolic+FBmod+9-El LPDA UHF Raw Gain Note loss of F/B & F/R Ratios on lower freqs enlarge 192KB, 1152x678 5 CM-4251 Parabolic+FBmod+9-El LPDA UHF SWR (300-ohms) Under 1.9 enlarge 253KB, 1152x678 6 CM-4251 Parabolic+FBmod+9-El LPDA UHF Impedance enlarge 301KB, 1024x1024 7 CM-4251 Parabolic+FBmod+9-El LPDA Azimuthal Pattern at 470 MHz enlarge 301KB, 1024x1024 8 CM-4251 Parabolic+FBmod+9-El LPDA Azimuthal Pattern at 530 MHz enlarge 303KB, 1024x1024 9 CM-4251 Parabolic+FBmod+9-El LPDA Azimuthal Pattern at 590 MHz enlarge 300KB, 1024x1024 10 CM-4251 Parabolic+FBmod+9-El LPDA Azimuthal Pattern at 650 MHz enlarge 298KB, 1024x1024 11 CM-4251 Parabolic+FBmod+9-El LPDA Azimuthal Pattern at 698 MHz enlarge 300KB, 1024x1024 12 CM-4251 Parabolic+FBmod+9-El LPDA Azimuthal Pattern at 758 MHz enlarge 303KB, 1024x1024 13 CM-4251 Parabolic+FBmod+9-El LPDA Azimuthal Pattern at 806 MHz enlarge 135KB, 602x1024 14 CM-4251 Parabolic+FBmod+9-El LPDA Side View [1 large square = 12.5 inches] enlarge 46KB, 791x1024 15 CM-4251 Parabolic+FBmod+9-El LPDA 4nec2 File
Select All.
Sign the Guestbook. There are no entries.