FYI: I've added 4nec2 analysis for several Yagi Antennas:http://imageevent.com/holl_ands/yagis
New ones include:
a) UHF 7-Element Folded Dipole (FD) Yagi
, Optimized by nikiml, UHF Raw Gain = 8.3 to 12.1 dBi, F/B & F/R Ratio Minimum = 10.4 dB (FAIR).
b) UHF 7-Element Folded Dipole (FD) Yagi
, with UHF Raw Gain = 7.8 to 11.2 dBi (slight reduction) with increased F/R & F/B Ratio Minimum = 14.6 dB (GOOD).
c) UHF 8-Element Folded Dipole Yagi (with 2 Reflector Rods), provides UHF Raw Gain = 8.2 to 11.7 dBi, F/B & F/R Ratio Minimum = 20.6 dB (EXCELLENT).
d) UHF 12-Element Folded Dipole Yagi
, provides UHF Raw Gain = 8.2 to 12.7 dBi, F/B & F/R Ratio Minimum = 15.6 dB (GOOD), but SWR under 3.2 (FAIR) needs improvement.
e) UHF 13-Element Folded Dipole Yagi (with 2 Reflector Rods), provides UHF Raw Gain = 9.3 to 13.4 dBi, F/B & F/R Ratio Minimum = 22.3 dB (EXCELLENT).
BTW: Although I "requested" only 1 dB Gain increase across the New UHF Band (to compensate for higher Balun Loss prior to Preamp), the result curves were much more than needed: 3.5 to 4 dB increase....so the lower frequencies are disadvantaged when using a Preamp...but the larger difference is in the desired ballpark if NOT using a Preamp.
PS: When I deleted the F/B & F/R Ratio Optimization requirements, Raw Gain only increased 0.5 to 1.0 dB...hardly worth throwing away the above Good to Excellent F/B & F/R Ratio performance.
I also recently uploaded 4nec2 analysis for:
f) Vertically Stacked UHF 8-El Folded Dipole Yagis (2 Reflector Rods Each):
UHF Raw Gain = 11.3 to 14.5 dBi, F/B & F/R Ratio Minimum = 22.2 dB (EXCELLENT) and SWR Under 3.0.
g) Various UHF 7-El Bi-Quagi, 7/8-El Bi-Quad Yagis and a 15-Element "Double Bi-Quad"
that did not compare very well to the Stacked 8-El FD-Yagis just referenced
h) UHF 7-El and 8-El "VEE" LPDA's:
Raw Gain was EXTREMELY FLAT: 8.6 dB (+/- 0.2 dB), F/B & F/R Ratio Minimum = 27.2 dB (EXCELLENT).Edited by holl_ands - 7/6/13 at 6:28pm