New CM4228HD (8" Whiskers x 8" Spacing) with Hollands Horizontal Harness (HHH) replacing the Original Harness analyzed using 4nec2. Dimensions of HHH OPTIMIZED using nikiml's Python Control Scripts were the WIDTH of the Feedline and X-Axis SEPARATION from the Center of the Bowties, similar to 2x2 4-Bay (H4) as well as the Vertically Stacked 4-Bay Antenna designs.
Optimized Dimensions: Xh = - 2.60-in = Separation between Feedlines and Center of Bowties. Diagonal Wire Lengths, Harness to Feedline = 3.18-in (Top-Left & Bottom-Right) AND = 2.84-in (Bottom-Left & Top-Right). Yinner = 10.80-in = Y-Axis Distance from Harness to INNER Bowtie Feedline (Top-Left & Bottom-Right). Youter = 10.85-in = Y-Axis Distance from Harness to OUTER Bowtie Feedline (Bottom-Left & Top-Right).
[Since difference of +/- 1/8-inch won't make much difference in performance, can round Harness Wire Half-Lengths to 8.75-in and Diagonal Wire Lengths to 3.0-in, demonstrating there was no need for separate SYmbols.]
UHF Raw Gain = 15.0 to 14.9 to 16.5 dBi, F/B & F/R Ratio Min = 19.1 dB and SWR (300-ohms) Under 2.3. These are significant improvements over the AS-SHIPPED CM4228HD version.
Hi-VHF Raw Gain = 4.3 to 12.9 dBi and SWR (300-ohms) = 14.2 to 9.8 to 61.9 is Excessive.
PS: Views with Reflector Removed are included to facilitate seeing the HHH. Note that Optimizer determined Harness Wire Lengths, rather than constraining them to be 1/2 the Bay Separation, as presumed in some OTHER HHH designs.
===================================================== Parametric Sweeps (Calculate/Start Optimizer in 4nec2) were used to investigate sensitivity to changes in HHH Dimensions (see Images 44+).
Raw Gain and SWR were very insensitive to changes in either Gap, Xh, Youter=Yinner or Rharn with only a few tenths of change to SWR and only a few tenths of a dB change to F/B & F/R Ratios over the fairly wide range of HHH dimensions tested.
===================================================== ERRATA (12Jul2014): Typo found in above text (HHH Diagram showed correct values). Yinner = Youter = 10.8+ inches (NOT 8.8-in).
EDIT (12JUL2014): Added Parametric Sweeps to investigate HHH sensitivity to changes.
EDIT (5Apr2016): Added missing (2.84") Dimension for Upper Left Short Diagonal Wire in HHD Dimensional Drawing.
EDIT (20Mar2017): Added Tine Separation to HHH Dimensional Drawing. Added "UHF" to Labels to emphasize that THIS HHH Version was Optimized for UHF-ONLY, to differentiate from newer Hi-VHF/UHF HHH's.
EDIT (3Apr2017): Added Elevation Pattern Charts showing NULL at about 40-45 degrees.
Date(s): 26 May 2014. Album by holl_ands. 1 - 47 of 47 Total. 6174 Visits.
enlarge 206KB, 1024x1015 1 CM4228HD with UHF Hollands Horiz Harness 3D View
enlarge 270KB, 1024x817 2 CM4228HD with UHF Hollands Horiz Harness Front View [1 large square = 5-inches]
enlarge 74KB, 288x1024 3 CM4228HD with UHF Hollands Horiz Harness Top View [1 large square = 5-inches]
enlarge 175KB, 1024x675 4 CM4228HD with UHF Hollands Horiz Harness UHF Raw Gain = 15.0 to 14.9 to 16.5 dBi UHF F/B & F/R Minimum = 19.1 dB
enlarge 184KB, 1024x675 5 CM4228HD with UHF Hollands Horiz Harness UHF SWR (300-ohms) Under 2.3
enlarge 311KB, 1024x1024 7 CM4228HD with UHF Hollands Horiz Harness Azimuthal Pattern at 470 MHz
enlarge 311KB, 1024x1024 8 CM4228HD with UHF Hollands Horiz Harness Azimuthal Pattern at 530 MHz
enlarge 314KB, 1024x1024 9 CM4228HD with UHF Hollands Horiz Harness Azimuthal Pattern at 590 MHz
enlarge 314KB, 1024x1024 10 CM4228HD with UHF Hollands Horiz Harness Azimuthal Pattern at 650 MHz
enlarge 314KB, 1024x1024 11 CM4228HD with UHF Hollands Horiz Harness Azimuthal Pattern at 698 MHz
enlarge 317KB, 1024x1024 12 CM4228HD with UHF Hollands Horiz Harness Azimuthal Pattern at 806 MHz
enlarge 313KB, 1024x1024 13 CM4228HD with UHF Hollands Horiz Harness Elevation Pattern at 470 MHz
enlarge 311KB, 1024x1024 14 CM4228HD with UHF Hollands Horiz Harness Elevation Pattern at 530 MHz
enlarge 311KB, 1024x1024 15 CM4228HD with UHF Hollands Horiz Harness Elevation Pattern at 590 MHz
enlarge 311KB, 1024x1024 16 CM4228HD with UHF Hollands Horiz Harness Elevation Pattern at 650 MHz
enlarge 311KB, 1024x1024 17 CM4228HD with UHF Hollands Horiz Harness Elevation Pattern at 698 MHz
enlarge 309KB, 1024x1024 18 CM4228HD with UHF Hollands Horiz Harness Elevation Pattern at 806 MHz
enlarge 211KB, 1024x696 19 Compare 8-Bay Antennas: CM4228HD As Shipped CM4228HD with RF Combiner Mod CM4228HD with UHF Hollands Horizontal Harness
enlarge 51KB, 791x1024 20 UHF CM4228HD with UHF Hollands Horiz Harness 4nec2 File (incl. Python Control Script)
enlarge 87KB, 265x1024 21 CM4228HD with UHF Hollands Horiz Harness Side View [1 large square = 2.5-inches]
enlarge 182KB, 1024x675 22 CM4228HD with UHF Hollands Horiz Harness Raw Gain, F/B & F/R Ratio vs Tine Separation Wide Range: Up to 3 dB Variation Optimizer does NOT choose Max Gain at 470 MHz
enlarge 191KB, 1024x675 23 CM4228HD with UHF Hollands Horiz Harness Raw Gain, F/B & F/R Ratio vs Tine Separation Mid-Range: Optimizer chose TineSep = 3.87-in
enlarge 187KB, 1024x675 24 CM4228HD with UHF Hollands Horiz Harness Raw Gain, F/B & F/R Ratio vs Tine Separation Narrow Range: NOTE DISAGREEMENT with Mid-Range View
enlarge 178KB, 1024x675 25 CM4228HD with UHF Hollands Horiz Harness Raw Gain, F/B & F/R Ratio vs Bow Sweep Wide Range: CM4228HD Model sets BowSwp=0.00
enlarge 178KB, 1024x675 26 CM4228HD with UHF Hollands Horiz Harness Raw Gain, F/B & F/R Ratio vs Bow Sweep Mid-Range: Over 1 dB Loss away from BowSwp=0.00
enlarge 180KB, 1024x675 27 CM4228HD with UHF Hollands Horiz Harness Raw Gain, F/B & F/R Ratio vs Bow Sweep Takes only +/- 0.02-in to Lose over 1 dB Raw Gain
enlarge 195KB, 1024x675 28 CM4228HD with UHF Hollands Horiz Harness Hi-VHF Raw Gain = 4.3 to 12.9 dBi Hi-VHF F/B & F/R: Narrow Dropoff near 196.5 MHz
enlarge 198KB, 1024x675 29 CM4228HD with UHF Hollands Horiz Harness Hi-VHF SWR (300-ohms) = 14.2 to 9.8 to 61.9 is Excessive
enlarge 309KB, 1024x1024 31 CM4228HD with UHF Hollands Horiz Harness Azimuthal Pattern at 174 MHz
enlarge 314KB, 1024x1024 32 CM4228HD with UHF Hollands Horiz Harness Azimuthal Pattern at 196.5 MHz Bi-Directional over Narrow Freq Range
enlarge 317KB, 1024x1024 33 CM4228HD with UHF Hollands Horiz Harness Azimuthal Pattern at 216 MHz
enlarge 48KB, 791x1024 34 Hi-VHF CM4228HD with UHF Hollands Horiz Harness 4nec2 File (incl. Python Control Script)
enlarge 113KB, 711x1024 35 CM4228HD with Hollands Horiz Harness 3D View from REAR, with Reflector Removed
enlarge 195KB, 1024x768 36 CM4228HD with UHF Hollands Horiz Harness 3D View DETAIL from REAR, with Reflector Removed
enlarge 328KB, 1024x892 37 CM4228HD with UHF Hollands Horiz Harness Front View, with Reflector Removed [1 large square = 2.5-inches]
enlarge 91KB, 260x1024 38 CM4228HD with Hollands Horiz Harness Top View, with Reflector Removed [1 large square = 2.5-inches]
enlarge 89KB, 280x1024 39 CM4228HD with Hollands Horiz Harness Side View, with Reflector Removed [1 large square = 2.5-inches]
enlarge 173KB, 1024x675 40 CM4228HD with UHF Hollands Horiz Harness Parameter Sweep at 470 MHz Raw Gain vs Separation Between Harness Wires [Optimum Gap = 2.22-in]
enlarge 157KB, 1024x675 41 CM4228HD with UHF Hollands Horiz Harness Parameter Sweep at 470 MHz Raw Gain vs Separation of Harness Wires away from Plane of Bowties [Optimum Xh = - 2.60-in]
enlarge 169KB, 1024x675 42 CM4228HD with UHF Hollands Horiz Harness Parameter Sweep at 470 MHz Raw Gain vs Length of Harness Wires Parallel to Plane of Bowties [Optimum Youter = Yinner = 10.8-in]
enlarge 194KB, 1024x675 43 CM4228HD with UHF Hollands Horiz Harness Parameter Sweep at 470 MHz SWR vs Separation Between Harness Wires [Optimum Gap = 2.22-in]
enlarge 168KB, 1024x675 44 CM4228HD with UHF Hollands Horiz Harness Parameter Sweep at 470 MHz SWR vs Separation of Harness Wires away from Plane of Bowties [Optimum Xh = - 2.60-in]
enlarge 184KB, 1024x675 45 CM4228HD with UHF Hollands Horiz Harness Parameter Sweep at 470 MHz SWR vs Length of Harness Wires Parallel to Plane of Bowties [Optimum Youter = Yinner = 10.8-in]
enlarge 162KB, 1024x675 46 CM4228HD with UHF Hollands Horiz Harness Parameter Sweep at 470 MHz Raw Gain vs Radius of Harness Wires [Assumed Rharn=Rfeed=0.059-in AWG10]
enlarge 182KB, 1024x675 47 CM4228HD with UHF Hollands Horiz Harness Parameter Sweep at 470 MHz SWR vs Radius of Harness Wires [Assumed Rharn=Rfeed=0.059-in AWG10]
Great Work ! I am going to try it as I get CH 25 RF 572-578 Mhz and Ch 38 620-626 Mhz breaking up mostly. Hope the increased gain with the UHF Only Harness solves my problem. I also intend to use a N1201SA Vector Impedance Meter to see the impedance. I have a feeling it is 150 Ohms rather then 300 OHms in said case two quarter wave RG63 125 Ohm Coax (accounting for Velocity Factor) will make a 2:1 Balun or I will use a CM0089 Balun that I have. - Howard | www.fcc1.biz, Mon, 11 Mar 2019 4:24PM
Great stuff here, holl_ands. Thanks for sharing it with folks! Lots of *great* work here!!!! - Intheswamp | www.beeweather.com, Wed, 18 Oct 2017 3:50PM
