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holl_ands | Home > Multi-Bay Bowtie Antennas > UHF 4-Bay Bowties with Reflector > Browse:Ch22 FF4 4-Bay Bowtie + DARNEW UHF Free-Form 4-Bay + FlatScreenReflUHF Free-Form 4-Bay + DblAnglReflUHF FF4 SingleAngleRefl - DeepSidelobesUHF M4 (10x9.5) Super-4-Bay+DARUHF M4 (9.5x9.0)+DAR Flat vs Swept BowsM4 (9.5x9.0)+DAR Flat v Swept BowsM4 (9.5x9) + Various FLAT Refl. WidthsM4 (9.5x9.0) + 40x34 FLAT Refl at 5-inUHF M4 (9.5x9.0) 4-Bay+FLAT Grid at 5.5"UHF M4 (9.5x9.0) 4-Bay+FLAT Grid at 16"M4 (9.5x9) + Various Number of RRs - OPTUHF KosmicSuperQuad+DAR FlatvsSwept BowsUHF Actual CM4221 Flat Bows & ReflectorUHF CM4221a.ez.nec Flat Bows & ReflectorUHF CM4221HD (Hacked) - 16 ReflRodsUHF CM-4221HD - 10-in WhiskersUHF CM4221HD (Hacked) + Director RodsCM4221HD (Hacked) + Stub FilterAntennacraft U-4000 - 9 Reflector RodsA-D Old DB-4 4-Bay Bowtie with Reflector
CM4221HD (Hacked) + Stub Filter UHF (New) CM4221HD 4-Bay with 16 Reflector Rods (23.6-in Wide, Sep=4.25-in) plus Stub Filter analyzed using 4nec2.  The Stub Filter was isolated from the Antenna and the load (presumed to be a Preamp) by additional transmission lines of the same Length as the Stub, because connecting Stub Filter directly to Antenna's Feedpoint caused problems. Two Stub Filters are analyzed, the first with a Half-Wave Length, which is reportedly "easier to control".  The second is the more commonly encountered Quarter-Wave Length: http://www.eham.net/ehamforum/smf/index.php?topic=17118.0;wap2 http://www.arcticpeak.com/antennapages/quaterwavestub.htm http://www.onlineconversion.com/frequency_wavelength.htm [Wavelength Calculator] a) Half-Wave Length Stub Filter with SHORTED End: A Length of 12-in (Notch on 492 MHz) was chosen to pass Ch14, while attenuating Ch15...which turned out to be fairly minimal, and completely ruined SWR Characteristics across ENTIRE UHF Band....so NOT very useful. b) Quarter-Wave Length Stub Filter with OPEN End: A Length of 6.15-in (Notch on 496 MHz) was chosen with even worse results.  Gain was greatly reduced on Ch14 with only minimal additional reduction on Ch15 and SWR was completely ruined across entire UHF Band. MORE RUNS PLANNED: Use Simulated Transmission Lines to see if better impedance matching helps. Date(s): 18 Dec 2013. Album by holl_ands. 1 - 30 of 30 Total. 3779 Visits.
enlarge 169KB, 941x1024 1 CM4221HD (Hacked) + Halfwave Stub Filter 3D View - Stub Length 12-in Note: Stub is SHORTED enlarge 294KB, 1024x1021 2 CM4221HD (Hacked) + Halfwave Stub Filter Side View - Stub Length 12-in [1 large square = 2.5 inches] enlarge 244KB, 1024x850 3 CM4221HD (Hacked) + Stub Filter Top View - Stub Length 12-in [1 large square = 2.5 inches] enlarge 196KB, 1152x714 4 CM4221HD (Hacked) + Halfwave Stub Filter Stub Length 12-in UHF Raw Gain (dBi) enlarge 212KB, 1152x714 5 CM4221HD (Hacked) + Halfwave Stub Filter Stub Length 12-in UHF SWR (300-ohms) enlarge 294KB, 1152x714 6 CM4221HD (Hacked) + Halfwave Stub Filter Stub Length 12-in UHF Impedance enlarge 205KB, 1152x714 7 CM4221HD (Hacked) + Halfwave Stub Filter Stub Length 12-in Ch14-17 Raw Gain (dBi) enlarge 227KB, 1152x714 8 CM4221HD (Hacked) + Halfwave Stub Filter Stub Length 12-in Ch14-17 SWR (300-ohms) enlarge 264KB, 1152x714 9 CM4221HD (Hacked) + Halfwave Stub Filter Stub Length 12-in Ch14-17 Impedance enlarge 293KB, 1024x1024 10 CM4221HD (Hacked) + Halfwave Stub Filter Stub Length 12-in Azimuthal Pattern at 470 MHz enlarge 293KB, 1024x1024 11 CM4221HD (Hacked) + Halfwave Stub Filter Stub Length 12-in Azimuthal Pattern at 473 MHz enlarge 294KB, 1024x1024 12 CM4221HD (Hacked) + Halfwave Stub Filter Stub Length 12-in Azimuthal Pattern at 476 MHz enlarge 291KB, 1024x1024 13 CM4221HD (Hacked) + Halfwave Stub Filter Stub Length 12-in Azimuthal Pattern at 479 MHz enlarge 291KB, 1024x1024 14 CM4221HD (Hacked) + Halfwave Stub Filter Stub Length 12-in Azimuthal Pattern at 482 MHz enlarge 40KB, 791x1024 15 CM4221HD (Hacked) + Halfwave Stub Filter Stub Length 12-in 4nec2 File enlarge 148KB, 761x1024 16 CM4221HD (Hacked) + Quarterwave Stub 3D View - Stub Length 6.15-in Note: Stub is OPEN enlarge 197KB, 661x1024 17 CM4221HD (Hacked) + Quarterwave Stub Side View - Stub Length 6.15-in [1 large square = 2.5 inches] enlarge 197KB, 777x1024 18 CM4221HD (Hacked) + Quarterwave Stub Top View - Stub Length 6.15-in [1 large square = 2.5 inches] enlarge 192KB, 1152x714 19 CM4221HD (Hacked) + Quarterwave Stub Stub Length 6.15-in UHF Raw Gain (dBi) enlarge 231KB, 1152x714 20 CM4221HD (Hacked) + Quarterwave Stub Stub Length 6.15-in UHF SWR (300-ohms) is EXCESSIVE enlarge 270KB, 1152x714 21 CM4221HD (Hacked) + Quarterwave Stub Stub Length 6.15-in UHF Impedance enlarge 224KB, 1152x714 22 CM4221HD (Hacked) + Quarterwave Stub Stub Length 6.15-in Ch14-17 Raw Gain (dBi) is Very Low Notch on 486 MHz enlarge 220KB, 1152x714 23 CM4221HD (Hacked) + Quarterwave Stub Stub Length 6.15-in Ch14-17 SWR (300-ohms) is EXCESSIVE enlarge 274KB, 1152x714 24 CM4221HD (Hacked) + Quarterwave Stub Stub Length 6.15-in Ch14-17 Impedance enlarge 310KB, 1024x1024 25 CM4221HD (Hacked) + Quarterwave Stub Stub Length 6.15-in Azimuthal Pattern at 470 MHz enlarge 306KB, 1024x1024 26 CM4221HD (Hacked) + Quarterwave Stub Stub Length 6.15-in Azimuthal Pattern at 473 MHz enlarge 304KB, 1024x1024 27 CM4221HD (Hacked) + Quarterwave Stub Stub Length 6.15-in Azimuthal Pattern at 476 MHz enlarge 308KB, 1024x1024 28 CM4221HD (Hacked) + Quarterwave Stub Stub Length 6.15-in Azimuthal Pattern at 479 MHz enlarge 310KB, 1024x1024 29 CM4221HD (Hacked) + Quarterwave Stub Stub Length 6.15-in Azimuthal Pattern at 486 MHz [NOTCH] enlarge 40KB, 791x1024 30 CM4221HD (Hacked) + Quarterwave Stub Stub Length 6.15-in 4nec2 File
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