UHF 14-Element "VEE" Log Periodic Dipole Array (LPDA) Antenna with Shorting Stub, Optimized using nikiml's Python Scripts, then analyzed using 4nec2.
Optimum sweep angle was about 2 degrees to the REAR, similar to other Optimized "VEE" LPDAs, which is very close to a non-swept LPDA.
Raw Gain increased ONLY about 1 dB more than 8-El "VEE" LPDA, illustrating the biggest disadvantage of LPDA vs Yagi Antennas. However, F/R & F/R Ratios were HUGE with very good SWR (but for 75-ohms so must use a 1:1 Balun).
UHF Raw Gain = 11.8 to 10.4 dBi, F/B & F/R Ratio Min. = 22.2 dB and SWR (75-ohms) Under 1.4.
NOTE: Python Control *.bat text File presumes that all test files are in the c:\Python33 sub-directory, whereas all earlier postings have presumed c:\Python27, so adjust as necessary. My num-cores=6 (aka "threads" for i5 & i7 with 2 threads per core) also needs to be set for your processor. I just upgraded desktop from AMD Phenom II X3 to X6 (used here) and on i7 Laptop I reserve one "thread" for web surfing & checking prelim results, so num-cores=7.
Date(s): 14 Jul 2013. Album by holl_ands. 1 - 16 of 16 Total. 2180 Visits.
enlarge 78KB, 1018x1024 1 UHF 14-El VEE LPDA + Shorting Stub - OPT 3D View
enlarge 89KB, 1152x309 2 UHF 14-El VEE LPDA + Shorting Stub - OPT Front View Shorting Stub Length = 0.25-inches, interconnecting the two rear element halves [1 large square = 1.25 inches]
enlarge 130KB, 1152x410 3 UHF 14-El VEE LPDA + Shorting Stub - OPT Top View [1 large square = 5 inches]
enlarge 188KB, 1152x678 4 UHF 14-El VEE LPDA + Shorting Stub - OPT UHF Raw Gain = 11.8 to 10.4 dBi UHF F/B & F/R Ratio Minimum = 22.2 dB
enlarge 204KB, 1152x678 5 UHF 14-El VEE LPDA + Shorting Stub - OPT UHF SWR (75-ohms) Under 1.4
