UHF 2-Bay Hourglass-Loops analyzed using 4nec2. All dimensions were determined using nikiml's Python Optimization Scripts.
SAME as analysis for Vertical Stacked Hourglass-Loops found here: http://imageevent.com/holl_ands/stacked/verticallystackeduhf/vertstackuhfhourglassloopnorefl
UHF Hourglass-Loop has a VERY WIDE Beamwidth of 80-deg at 470 MHz, decreasing to 70-deg at 698 MHz. Vertically Stacked, remains 80-deg at 470 MHz, decreasing to 60-deg at 698 MHz (to within 10-deg resolution).
Two versions are presented here, the first presumes the use of an RF Combiner attached to Antenna Feedpoints using Baluns & Equal Length Cables. The second avoids 0.5-1.5+ dB Loss in RF Combiner by using an Optimized Vertical Interconnection Harness.
a) RF Combiner: Vertical Stacking (Center-Center), VD = 18-in provides Max Raw Gain per Optimizer.
UHF Raw Gain = 7.6 to 9.6 dBi and SWR (300-ohms) under 1.9. Hi-VHF Raw Gain = 4.4 to 4.9 dBi and SWR (300-ohms) = 103 to 33 is Excessive.
===================================== b) Holl_ands Vertical Harness: Vertical Stacking (Center-Center), VD = 24.75-in provides Max Raw Gain per Optimizer. See 4nec2 File for all Dimensions, including Re-Optimized Hourglass-Loop sizes.
UHF Raw Gain FORWARD = 7.8 to 9.7 dBi, F/B & F/R Ratio has small (1.3 dB) increase at high frequencies (just -0.1 dB at low frequencies), and SWR (300-ohms) under 2.1. Hi-VHF Raw Gain = 4.6 to 5.6 dBi and SWR (300-ohms) = 67 to 33 is Excessive.
Dimensions of HVH wires were determined using nikiml's Python Optimization Scripts: VS = 12.25-in = Vertical Stacking Distance (Center-To-Center). VS/2 = 6.125-in, Length of Harness wires from Feedpoint to Center of each Hourglass-Loop. Diagonal = 3.25-in, Length from Harness Wires to each Hourglass-Loop Feedpoint. Hw = 0.80-in (may round to 0.75-in), Xh = -3.25-in = Harness X-Axis Separation from Hourglass-Loops. TOTAL HARNESS WIRE LENGTH (2 required) = 19.75-in = 2x6.125+2x3.25+2x0.5 (for eyelets)
Date(s): 19 Nov 2014. Album by holl_ands. 1 - 42 of 42 Total. 5723 Visits.
enlarge 58KB, 522x1024 1 Vert-Stack UHF Hourglass-Loop - NO Refl RF Combiner + Equal-Length Coax + Baluns 3D View
enlarge 174KB, 517x1024 2 Vert-Stack UHF Hourglass-Loop - NO Refl RF Combiner + Equal-Length Coax + Baluns Front View [1 large square = 2.5-inches]
enlarge 87KB, 327x1024 3 Vert-Stack UHF Hourglass-Loop - NO Refl RF Combiner + Equal-Length Coax + Baluns Top View [1 large square = 1.25-inches]
enlarge 168KB, 1024x675 4 Vert-Stack UHF Hourglass-Loop - NO Refl RF Combiner + Equal-Length Coax + Baluns UHF Raw Gain = 7.6 to 9.6 dBi
enlarge 67KB, 560x1024 22 Vert-Stack UHF Hourglass-Loop - NO Refl Holl_ands Vertical Harness 3D View
enlarge 169KB, 510x1024 23 Vert-Stack UHF Hourglass-Loop - NO Refl Holl_ands Vertical Harness Front View [1 large square = 2.5-inches]
enlarge 93KB, 304x1024 24 Vert-Stack UHF Hourglass-Loop - NO Refl Holl_ands Vertical Harness Side View [1 large square = 2.5-inches]
enlarge 161KB, 1024x675 25 Vert-Stack UHF Hourglass-Loop - NO Refl Holl_ands Vertical Harness UHF Raw Gain FORWARD = 7.8 to 9.7 dBi [F/B & F/R Ratios NOT CALCULATED]
enlarge 164KB, 1024x675 26 Vert-Stack UHF Hourglass-Loop - NO Refl Holl_ands Vertical Harness UHF Raw Gain = 7.8 to 8.8 to 8.3 dBi to REVERSE UHF F/B & F/R Ratio shows slight (1.3 dB) increase towards the FRONT at higher frequencies
enlarge 192KB, 1024x675 27 Vert-Stack UHF Hourglass-Loop - NO Refl Holl_ands Vertical Harness UHF SWR (300-ohms) Under 2.1
enlarge 309KB, 1024x1024 28 Vert-Stack UHF Hourglass-Loop - NO Refl Holl_ands Vertical Harness Azimuthal Pattern at 470 MHz
enlarge 310KB, 1024x1024 29 Vert-Stack UHF Hourglass-Loop - NO Refl Holl_ands Vertical Harness Azimuthal Pattern at 530 MHz
enlarge 310KB, 1024x1024 30 Vert-Stack UHF Hourglass-Loop - NO Refl Holl_ands Vertical Harness Azimuthal Pattern at 590 MHz
enlarge 310KB, 1024x1024 31 Vert-Stack UHF Hourglass-Loop - NO Refl Holl_ands Vertical Harness Azimuthal Pattern at 650 MHz
enlarge 310KB, 1024x1024 32 Vert-Stack UHF Hourglass-Loop - NO Refl Holl_ands Vertical Harness Azimuthal Pattern at 698 MHz
enlarge 304KB, 1024x1024 33 Vert-Stack UHF Hourglass-Loop - NO Refl Holl_ands Vertical Harness Azimuthal Pattern at 758 MHz
enlarge 300KB, 1024x1024 34 Vert-Stack UHF Hourglass-Loop - NO Refl Holl_ands Vertical Harness Azimuthal Pattern at 806 MHz
