☰

Public Gallery>holl_ands>Miscellaneous>Browse:Olivia Newton-John concert in SF.....Pumpkin for dogsOlivia @ Feather FallsTowbe's Adventurers 2014College of the CanyonsJohn Burroughs High School StadiumCerritos College StadiumUKC GRAND CH K2'S Bad Boy HolidayVeniceEast LA CollegeLas Vegas Rock Veneer coming off 7.2014T206From_BroH-Stack UHF Hourglass-Loop + 15RRFOURTH OF JULY WEEKEND 2014Old CM4228 with Hollands Horiz HarnessApronsDog SweatersToy Rat Terrier PuppiesUKC CH Atencio's Blowing Wild of K2Led Zepagain At The Grove!Queen Nation @ The Grove of AnaheimRenovation: St. Matthew's, CharlestonUKC Ch. "PR" Slick's Whispering WindsGame Worn Football JerseysLA SANTA CECILIA AT THE RIALTO THEATRERFIModel railways 5JulianaScotland and Ireland Next 14|Show all

Old CM4228 with Hollands Horiz Harness Slideshow Old CM4228 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 (Gap) 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.  Bowtie Tine Separation and Sweep were also Optimized. When surveying the "terrain", I noticed that original CM4228a model (posted by Ken Nist on HDTVPrimer) did NOT include the two 1.25-in Diameter Tubes which support the Bowtie/Feedline structures. Since HHH could intersect or be influenced by the close proximity, I added Vertical Tubes to MY CM4228 (8.0x8.0) model, which uses MY ACTUAL MEASUREMENTS.  This significantly improved SWR and the low frequency roll-off problem found in Ken Nist's model, as shown in Charts.  To facilitate Apples-to-Apples comparisons, I also reran the RF Combiner Mod version after adding the Vertical Tubes. Two HHH versions were Optimized to determine the "best": ALT#1 - HHH is In-between Bowties and Reflector, providing best UHF & Hi-VHF performance. ALT#2 - HHH is In-front of Bowties, included here in case a user prefers that arrangement. ################################################################## ALT#1 - Optimized Dimensions for HHH In-between Bowties and Reflector: Tine Sep = 4.0-in, NO Sweep.  Gap = 1.3-in (about 1.25-in) = Separation between Feedlines, Xh = - 1.12-in = Separation between Feedlines and Center of Bowties.  Diagonal Wire Lengths, Harness to Feedline = 2.69-in (Top-Left & Bottom-Right) AND = 1.67-in (Bottom-Left & Top-Right). Yinner = 11.71-in = Y-Axis Distance from Harness to INNER Bowtie Feedline (Top-Left & Bottom-Right). Youter = 11.71-in = Y-Axis Distance from Harness to OUTER Bowtie Feedline (Bottom-Left & Top-Right). Each HHH wire Length = 16.07-in + 2 x 0.715-in eyelets on ends = 17.5-in. TOTAL. Whatever lengths is needed to get around obstacles near attachment screws are to be subtracted from Harness Length along Y-Axis, maintaining 1.12-in Separation between Harness and Bowties. UHF Raw Gain = 14.8 to 14.7 to 17.8 dBi, F/B & F/R Min = 21.9 dB and SWR (300-ohms) Under 2.1. Hi-VHF Raw Gain = 5.0 to 10.4 dBi, Peaky on Ch9, Hi-VHF F/B & F/R Ratio Minimum = 10.3 dB and SWR (300-ohms) under 5.1. Still, these are significant improvements over the AS-SHIPPED CM4228 version. Views with Reflector Removed are included to facilitate seeing the HHH. ################################################################## ALT#2 - Optimized Dimensions for HHH In-Front of Bowties: Optimum Tine Sep = 3.125-in, NO Sweep.  Gap = 0.92-in (about 1.0-in) = Separation between Feedlines, Xh = -2.21-in = Separation between Feedlines and Center of Bowties.  Diagonal Wire Lengths, Harness to Feedline = 3.18-in (Top-Left & Bottom-Right) AND = 4.19-in (Bottom-Left & Top-Right). Yinner = 12.9-in (about 13.0-in) = Y-Axis Distance from Harness to INNER Bowtie Feedline (Top-Left & Bottom-Right). Youter = 12.9-in (about 13.0-in) = Y-Axis Distance from Harness to OUTER Bowtie Feedline (Bottom-Left & Top-Right). Each HHH wire Length = 20.27-in + 2 x 0.74-in eyelets on ends = 21.75-in. TOTAL. Whatever lengths is needed to get around obstacles near attachment screws are to be subtracted from Harness Length along Y-Axis, maintaining 2.21-in Separation between Harness and Bowties. UHF Raw Gain = 13.5 to 17.0 dBi, F/B & F/R Min = 19.9 dB and SWR (300-ohms) Under 2.6. Hi-VHF Raw Gain = 8.7 to 6.4 to 9.3 dBi, but 2.5 dB NULL on Ch9 could be a Problem Hi-VHF F/B & F/R Ratio Minimum about 10 dB, Except for DIP on Ch9 and SWR (300-ohms) = 24.2 to 2.3 to 4.4. Although significantly lower Gain than ALT#1, these are small improvements over AS-SHIPPED CM4228 version. 3 Jul 20141 - 40 of 54 Images5439 visitsAlbum by holl_ands

enlarge 275KB, 1024x696 Old CM4228 - Compare Raw & Net Gain For Nist Model vs Adding Vertical Tubes. Then Compare to HHH (Hollands Horiz Harness) Between Bowties & Reflector or In-Front. enlarge 261KB, 1024x696 Old CM4228 - Compare F/R & F/B Ratios For Nist Model vs Adding Vertical Tubes. Then Compare to HHH (Hollands Horiz Harness) Between Bowties & Reflector or In-Front. enlarge 149KB, 1024x696 Old CM4228 - Compare SWR For Nist Model vs Adding Vertical Tubes. Then Compare to HHH (Hollands Horiz Harness) Between Bowties & Reflector or In-Front. enlarge 341KB, 1024x1015 Old CM4228 with Hollands Horiz Harness ALT#1 HHH Between Bowties & Reflector 3D View enlarge 364KB, 997x1024 Old CM4228 with Hollands Horiz Harness ALT#1 HHH Between Bowties & Reflector Front View [1 large square = 5-inches] enlarge 80KB, 307x1024 Old CM4228 with Hollands Horiz Harness ALT#1 HHH Between Bowties & Reflector Top View [1 large square = 5-inches] enlarge 411KB, 1024x1015 Old CM4228 with Hollands Horiz Harness ALT#1 HHH Between Bowties & Reflector 3D View DETAIL enlarge 471KB, 1024x1015 Old CM4228 with Hollands Horiz Harness ALT#1 HHH Between Bowties & Reflector Front View DETAIL [1 large square = 2.5-inches] enlarge 89KB, 254x1024 Old CM4228 with Hollands Horiz Harness ALT#1 HHH Between Bowties & Reflector Side View [1 large square = 5-inches] enlarge 163KB, 806x1024 Old CM4228 with Hollands Horiz Harness ALT#1 HHH Between Bowties & Reflector 3D View - DETAIL W/O REFLECTOR enlarge 335KB, 1024x890 Old CM4228 with Hollands Horiz Harness ALT#1 HHH Between Bowties & Reflector Front View - DETAIL W/O REFLECTOR [1 large square = 5-inches] enlarge 82KB, 243x1024 Old CM4228 with Hollands Horiz Harness ALT#1 HHH Between Bowties & Reflector Top View - DETAIL W/O REFLECTOR [1 large square = 5-inches] enlarge 188KB, 1024x675 Old CM4228 with Hollands Horiz Harness ALT#1 HHH Between Bowties & Reflector UHF Raw Gain = 14.8 to 14.7 to 17.8 dBi UHF F/B & F/R Ratio Minimum = 21.9 dB enlarge 186KB, 1024x675 Old CM4228 with Hollands Horiz Harness ALT#1 HHH Between Bowties & Reflector UHF SWR (300-ohms) Under 2.1 enlarge 225KB, 1024x675 Old CM4228 with Hollands Horiz Harness ALT#1 HHH Between Bowties & Reflector UHF Impedance enlarge 297KB, 1024x1024 Old CM4228 with Hollands Horiz Harness ALT#1 HHH Between Bowties & Reflector Azimuthal Pattern at 470 MHz enlarge 297KB, 1024x1024 Old CM4228 with Hollands Horiz Harness ALT#1 HHH Between Bowties & Reflector Azimuthal Pattern at 530 MHz enlarge 299KB, 1024x1024 Old CM4228 with Hollands Horiz Harness ALT#1 HHH Between Bowties & Reflector Azimuthal Pattern at 590 MHz enlarge 300KB, 1024x1024 Old CM4228 with Hollands Horiz Harness ALT#1 HHH Between Bowties & Reflector Azimuthal Pattern at 650 MHz enlarge 300KB, 1024x1024 Old CM4228 with Hollands Horiz Harness ALT#1 HHH Between Bowties & Reflector Azimuthal Pattern at 698 MHz enlarge 300KB, 1024x1024 Old CM4228 with Hollands Horiz Harness ALT#1 HHH Between Bowties & Reflector Azimuthal Pattern at 758 MHz enlarge 302KB, 1024x1024 Old CM4228 with Hollands Horiz Harness ALT#1 HHH Between Bowties & Reflector Azimuthal Pattern at 806 MHz enlarge 169KB, 791x1024 Old CM4228 with Hollands Horiz Harness ALT#1 HHH Between Bowties & Reflector 4nec2 File - UHF ONLY enlarge 168KB, 791x1024 Old CM4228 with Hollands Horiz Harness ALT#1 HHH Between Bowties & Reflector 4nec2 File - Hi-VHF ONLY enlarge 175KB, 1024x675 Old CM4228 with Hollands Horiz Harness ALT#1 HHH Between Bowties & Reflector Hi-VHF Raw Gain = 5.0 to 10.4 dBi, Peaky on Ch9 Hi-VHF F/B & F/R Ratio Minimum = 10.3 dB enlarge 190KB, 1024x675 Old CM4228 with Hollands Horiz Harness ALT#1 HHH Between Bowties & Reflector Hi-VHF SWR (300-ohms) Under 5.1 enlarge 226KB, 1024x675 Old CM4228 with Hollands Horiz Harness ALT#1 HHH Between Bowties & Reflector Hi-VHF Impedance enlarge 297KB, 1024x1024 Old CM4228 with Hollands Horiz Harness ALT#1 HHH Between Bowties & Reflector Azimuthal Pattern at 174 MHz enlarge 298KB, 1024x1024 Old CM4228 with Hollands Horiz Harness ALT#1 HHH Between Bowties & Reflector Azimuthal Pattern at 198 MHz enlarge 300KB, 1024x1024 Old CM4228 with Hollands Horiz Harness ALT#1 HHH Between Bowties & Reflector Azimuthal Pattern at 216 MHz enlarge 264KB, 690x1024 Old CM4228 with Hollands Horiz Harness ALT#2 HHH In-Front of Bowties 3D View enlarge 363KB, 1024x1001 Old CM4228 with Hollands Horiz Harness ALT#2 HHH In-Front of Bowties Front View [1 large square = 5-inches] enlarge 103KB, 306x1024 Old CM4228 with Hollands Horiz Harness ALT#2 HHH In-Front of Bowties Top View [1 large square = 5-inches] enlarge 386KB, 980x1024 Old CM4228 with Hollands Horiz Harness ALT#2 HHH In-Front of Bowties 3D View DETAIL enlarge 472KB, 1024x1015 Old CM4228 with Hollands Horiz Harness ALT#2 HHH In-Front of Bowties Front View - DETAIL [1 large square = 2.5-inches] enlarge 106KB, 312x1024 Old CM4228 with Hollands Horiz Harness ALT#2 HHH In-Front of Bowties Side View [1 large square = 5-inches] enlarge 185KB, 1024x675 Old CM4228 with Hollands Horiz Harness ALT#2 HHH In-Front of Bowties UHF Raw Gain = 13.5 to 17.0 dBi UHF F/B & F/R Minimum = 19.9 dB enlarge 190KB, 1024x675 Old CM4228 with Hollands Horiz Harness ALT#2 HHH In-Front of Bowties UHF SWR (300-ohms) Under 2.6 enlarge 230KB, 1024x675 Old CM4228 with Hollands Horiz Harness ALT#2 HHH In-Front of Bowties UHF Impedance enlarge 295KB, 1024x1024 Old CM4228 with Hollands Horiz Harness ALT#2 HHH In-Front of Bowties Azimuthal Pattern at 470 MHz

Next 14|Show all