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UHF SBGH + 2ea 36"x18" Screen Grid Refl. (8 Mar 2018)UHF SBGH + 2ea 36"x18" Split Screen Grid Reflectors analyzed using 4nec2,
including Parametric Analysis of Reflector-to-SBGH Separation distance (RS).
SBGH same as in nikiml's GH10 [10 RR pairs] to facilitate comparison to large Screen Grid Reflector.
UHF Raw Gain = 13.4 to 16.1 to 14.4 dBi, F/B & F/R Ratio Min. = 17.1 dB and SWR (300-ohms) Under 2.7.
UHF SWR is Under 2.7 for RS = 3.5 to 7.5-inches...and Best at RS = 5.5-inches.
Hi-VHF Raw Gain TO REAR = 5.6 to 7.2 to 6.8 dBi with F/B & F/R Ratio Min. = 14.9 dB and Very High SWR.
However LOW Forward Hi-VHF Gain [Wider Reflector "should" re-orient beam FORWARD.]
FWIW: Note that Hi-VHF Gain is Best for RS ~ 12-inches....which unfortunately also degrades UHF Gain & SWR.
Compared to nikiml's GH10, Gain was about the same, except at 470 MHz it dropped about 1 dB,
but F/B & F/R Ratio Min. increased by over 10 dB:
http://clients.teksavvy.com/~nickm/gh_u/gh10_15u15.html |
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GH - nikiml EVAL Summaries (16 Dec 2016)Grey-Hoverman - EVAL Summaries for various Optimized Antennas posted on nikiml's website:
http://clients.teksavvy.com/~nickm/index.html
CLICK to open Thumbnail and SELECT HTML Version [ignore *.pdf version].
Will display 4nec2 Text File, Outline Figure, Azimuthal Patterns, Gain/SWR Curves and Results in Tabular Form. |
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Hoverman Type1 (NO Reflector) (27Aug2009)Hoverman Type 1 (NO Reflector) per US Patent 2,918,672, issued 22Dec1959, analyzed using 4nec2, assuming AWG12:
http://www.freepatentsonline.com/2918672.pdf
All 45-deg Zig-Zag and Horizontal Element Lengths L=7.0-in.
At Hi-VHF, Raw Gain is 3.5 to 5.5 dBi, but SWR is VERY EXCESSIVE.... |
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Hoverman Type 1 Omni-directional (4 Sep 2009)Hoverman Type 1 Omni-directional per US Patent 2,918,672, issued 22Dec1959, analyzed using 4nec2.
Actually it is Bi-Directional or Quasi-Omni, but NOT True Omni-Directional. |
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Hoverman Type-2 with 4 Split RR Pair's (29 May 2017)Hoverman Type 2 with 4 Reflector Rod Pairs [each with a Mid-Point Gap] analyzed using 4nec2.
Hoverman Type 1 (NO Reflector) per US Patent 2,918,672, issued 22Dec1959, analyzed using 4nec2, assuming AWG12:
http://www.freepatentsonline.com/2918672.pdf
All 45-deg Zig-Zag and Horizontal Element Lengths L=7.0-in.
If built per Patent, Type-2 would not cover up through Ch52.
Shortening Horizontal ELements from 7-inches to 5.0 to 6.25-inches will. |
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Hoverman Type 2 w 4 RRs - Radio Shack (4 Apr 2013)Radio-Shack "4-Bay" "Spike" variation of Hoverman Type 2 with 4 Reflector Rods analyzed using 4nec2,
as depicted in R-S 1971 Catalog: http://www.radioshackcatalogs.com/html/1971-c/h292.html
Dimensions per alwjoplinmo and EscapeVelocity, 4nec2 by alwjoplinmo, with AWG10 Elements and 3/8" O.D. RR's.
Original Hoverman Patent US3148371, dated 8Sep1964, for the Type 2 (adds 4 SPLIT Reflector Rod Pairs)
does NOT have the short "Spikes" at the ends of the outer whiskers and at the center Feedpoints:
http://www.freepatentsonline.com/3148371.pdf
All 45-deg Zig-Zag Lengths L=7.0-in, except Top & Bottom are 6.4-in plus 1.0-in Vertical Spur at Ends.
Vertical Spurs at Top & Bottom are unique to R-S versions, Length=5.1-in.
PS: For my version (see "HOVERMOON" photo below), I measure L=7.0-in with 6.5-in plus
1.25-in Vertical Spurs at Ends...and 5.25-in Vertical Spurs....a nearly negligible difference.
Note that the Spurs on the Ends actually turns back AROUND.
EDIT (5Mar2017): Added Hi-VHF Performance Charts. |
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SBGH - NO Reflector by Autofils (7 Jun 2013)UHF SBGH (Single Bay Grey-Hoverman) with NO Reflectors analyzed using 4nec2. AWG9 Elements assumed.
Dimensions per a 4nec2 file posted by user autofils, a modification of a 4nec2 file posted by user oldsparks.
All 45-deg Zig-Zag Lengths=7.07-in (180-mm) and Top/Bottom Horizontal "Spur" Lengths, Lspur = 5.6-in (142-mm),
as well as an earlier prototype version with Lspur = 5.0-in (127-mm), which had lower Gain in low end of UHF Band.
A Comparison Chart is provided at bottom for FF4, H2, nikikl's Optimized GH0 and various Hoverman versions.
======================================
Version (a), Lspur = 5.6-in
[See Dimensioned Diagram, ignoring GREEN lines for autofil's SBGH with 6-pairs of EQUAL LENGTH Reflector Rods]:
UHF Raw Gain = 6.7 to 11.2 to 10.5 dBi and SWR (300-ohms) under 3.2.
Hi-VHF Raw Gain = 3.1 to 4.7 dBi but SWR (300-ohms) = 22 to 26 is excessive.
======================================
Version (b), Lspur = 5.0-in:
UHF Raw Gain = 5.9 to 11.3 dBi and SWR (300-ohms) Under 3.2.
Hi-VHF Raw Gain = 2.9 to 4.3 dBi but SWR (300-ohms) = 24 to 28 is Excessive.
EDIT (5Mar2017): Added Hi-VHF Performance Charts.
EDIT (20Jun2019): Added version with Lspur = 5.6-in Horizontal "Spurs". |
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Antennacraft G-1483 Hoverman Type 2 (4 Apr 2013)Antennacraft G-1483 variation of (SBGH) Hoverman Type 2 (With 4 Reflector Rods) analyzed using 4nec2.
Dimensions per EscapeVelocity, 4nec2 file by <300ohm> as modified by holl_ands: added FR & RP Cards
to facilitate repeatable runs. |
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Antennacraft SuperG-1483 DBGH (1 Apr 2013)Antennacraft SuperG-1483 DBGH Gray-Hoverman Antenna analyzed using 4nec2.
High Gain in NEW UHF Band, but Front/Back, Front/Rear and Forward Sidelobes are much worse
than most other Hi-Gain Antennas. |
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Antennacraft Double-SuperG-1483 (1 Apr 2013)Antennacraft Double-SuperG-1483 Horizontally Stacked 2xDBGH Gray-Hoverman Antenna analyzed using 4nec2.
Very High Gain in NEW UHF Band, but Front/Back, Front/Rear and Forward Sidelobes are much worse
than most other Hi-Gain Antennas.
NOTE: Charts do NOT include RF Combiner Loss, which is "typically" 0.5 to 1.5+ dB, see:
www.antennahacks.com [Back-To-Back Combiner Loss - divide by two.] |
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Lo+Hi-VHF SBGH w NARODS (24 Nov 2012)Lo+Hi-VHF SBGH (Single Bay Grey-Hoverman) w NARODS analyzed using 4nec2.
Two versions were analyzed: GHn2 is constrained to about 89-in x 89-in with 4 NARODS in the middle.
GNn4 is a larger 98-in x 98-in with 8 NARODS in the middle, providing better Gain on Ch7-13.
GHn2 from nikiml's optimized 4nec2 file: http://clients.teksavvy.com/~nickm/gh_n_vV/gh2n_4v2_6V9.html
GHn2 provides about 4-5 dBi Gain in Ch2-9 and about 9 dBi gain on Ch10-13 with SWR under 2.9.
GHn4 from nikiml's optimized 4nec2 file: http://clients.teksavvy.com/~nickm/gh_n_vV/gh4n_4v75_10V7.html
GHn4 provides about 5-6 dBi Gain on Ch2-6 and 10-11 dBi Gain on Ch7-13 with SWR under 2.6. |
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SBGH Hi-VHF & UHF Combo - X0255/6 (6 Sep 2009)SBGH (Single Bay Gray-Hoverman) with 38 Resonator Rods (12 Hi-VHF, 24 UHF and 2 NARODs) analyzed using 4nec2.
WildWillie's X0255/X0256 design as modified by 300ohm for Symmetry and AutoGainTest.
Provides VERY GOOD performance on BOTH New UHF Band (Ch14-51) and Hi-VHF Band (Ch7-13).
BUT it's very BIG: 87-in H x 72-in W x 10.5-in D. |
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DBGH Hi-VHF & UHF Combo - 300ohm (31 Jan 2009 (UPDATE))DBGH (Double Bay Gray Hoverman) with 28 Reflector RODs (3/8-in O.D.). Combo Hi-VHF & UHF Antenna
Simulation Runs using 4nec2 for JUST the Ch9-10 Optimized Version. For alternative Ch7-8 and Ch11-13
Optimized Performance Summary & Dimensions, see last 4 images on this web page.
Antenna Design and original EZNEC file posted by <300ohm> on 16Jan2009 to:
http://www.digitalhome.ca/forum/showthread.php?t=99907
Slides 7-15 are UHF Band Performance. They illustrate the need to use BARE WIRE (vice Insulated) for UHF Band.
Above Ch47 had both Raw Gain Loss and additional Net Gain Loss due to SWR degradation.
Slides 16-24 are Hi-VHF Performance. Insulation had only minor impact...and actually IMPROVED CH7.
However, these detriments could appear in different forms in other designs...
Note poor F/B and F/R on all Hi-VHF except Ch9 & 10. Some Elements can be adjusted to reoptimize for either Ch7-8 or Ch11-13.
UPDATE 31Jan2009: Due to (inches vs meters) error in defining insulation thickness in 4nec2 file, updated all runs.
UPDATE 25Feb2019: Added nikiml EVAL Text File Summaries for Ch7-8, Ch9-10 and Ch11-13 alternative Versions. |
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SBGH Wide Beamwidth/Omni Investigations (10 Sept 2009)SBGH Wide Beamwidth Investigations (e.g. 60+degrees or multi-lobed), including higher Gain
Omnidirectional antennas analyzed using 4nec2.
In response to Vorg's situation in Tucson, AZ with THREE widely separated tower groups.
Includes following SBGH versions:
a. WW-X0412 by wildwillie: TWO Sets of Slanted Reflector Rods, 28 each Set.
b. WW-X0414 by wildwllie: One Set of 7 Slanted Reflector Rods: 3 irregularly shaped Lobes.
c. WW-X0418 by wildwillie: Elements Swept Forward + 28 Angled Reflector Rods: Nearly 180-deg coverage.
d. WW-X0418-Mod8: holl_ands Mod: 8 vice 28 Rods: More Rear Gain.
e. WW-X0418-Mod4: holl_ands Mod: 4 vice 28 Rods: Irregular, coming closer to Omni-directional coverage.
f. WW-X0418-Mod0: holl_ands Mod: NO Reflector Rods: Nearly Omni-directional coverage with 5-6+ dBi Raw Gain.
This is much more than a typical 2.15 dBi (0 dBd) Gain Omni-directional antenna.....or Rabbit-Ears. |
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DBGH Wide Beamwidth/Omni Investigations (12 Sep 2009)DBGH Wide Beamwidth Investigations (e.g. 60+degrees or multi-lobed), including higher Gain Omnidirectional antennas analyzed using 4nec2.
In response to Vorg's situation in Tucson, AZ with THREE widely separated tower groups.
Includes the following DBGH versions:
a. 300ohm-X0429, mod by 300ohm to wildwillies X0418-Mod0 (No Reflectors): Six Lobes, beamwidth varies with frequency.
b. XA-X0433, mod by XAuto to wildwillies X0418-Mod0 (No Reflectors): 2 Very Fat and 2 Narrow Beamwidth Lobes.
c. WW-X0442, wildwillies: 2 Fat and 1 Narrow Beamwidth Lobes.
d. WW-X0450 (aka WW-X0442 Rev3) by wildwillie: Quasi-Omni-Directional. |
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