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 holl_ands | Home > Gray-Hoverman Antennas > 
UHF SBGH + 2ea 36"x18" Screen Grid Refl.
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
Date(s): 8 Mar 2018. Album by holl_ands. 1 - 40 of 40 Total. 4828 Visits.
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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
3D View

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
Front View
[1 large square = 2.5-inches]

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
Top View
[1 large square = 2.5-inches]

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
UHF Raw Gain = 13.4 to 16.1 to 14.4 dBi
UHF F/B & F/R Ratio Minimum = 17.1 dB

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
UHF SWR (300-ohms) Under 2.7

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
UHF Impedance

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
Azimuthal Pattern at 470 MHz

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
Azimuthal Pattern at 530 MHz

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
Azimuthal Pattern at 590 MHz

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
Azimuthal Pattern at 650 MHz

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
Azimuthal Pattern at 698 MHz

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
Azimuthal Pattern at 806 MHz

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
470 MHz Raw Gain for RS = 2 to 22-inches

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
470 MHz SWR for RS = 2 to 22-inches

SWR Under 2.7 for RS = 3.5 to 7.5-inches

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
470 MHz Impedance for RS = 2 to 22-inches

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
584 MHz Raw Gain for RS = 2 to 22-inches

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
584 MHz SWR for RS = 2 to 22-inches

SWR Under 2.7 for RS = 3 to 9-inches

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
584 MHz Impedance for RS = 2 to 22-inches

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
698 MHz Raw Gain for RS = 2 to 22-inches

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
698 MHz SWR for RS = 2 to 22-inches

SWR Under 2.7 for RS = 3 to 10-inches

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
698 MHz Impedance for RS = 2 to 22-inches

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
Hi-VHF Raw Gain = 5.6 tto 7.2 to 6.8 dBi
Hi-VHF F/B & F/R Ratio Minimum = 14.9 dB

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
Hi-VHF SWR (300-ohms) is Very High

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
Hi-VHF Impedance

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
Azimuthal Pattern at 174 MHz

More Gain (6.0 dB) towards the Rear

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
Azimuthal Pattern at 198 MHz

More Gain (12.2 dB) towards the Rear

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
Azimuthal Pattern at 216 MHz

More Gain (8.7 dB) towards the Rear

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
Raw Gain at 174 MHz for RS = 2 to 22 inches
where RS = Reflector-to-SBGH Separation
Best when RS more than 12-inches

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
High SWR at 174 MHz for RS = 2 to 22 inches
where RS = Reflector-to-SBGH Separation

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
Impedance at 174 MHz for RS = 2 to 22 inches
where RS = Reflector-to-SBGH Separation

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
Raw Gain at 198 MHz for RS = 2 to 22 inches
Best when RS more than 12-inches

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
High SWR at 198 MHz for RS = 2 to 22 inches

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
Impedance at 198 MHz for RS = 2 to 22 inches

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
Raw Gain at 216 MHz for RS = 2 to 22 inches
Best when RS LESS than 12-inches

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
High SWR at 216 MHz for RS = 2 to 22 inches

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
Impedance at 216 MHz for RS = 2 to 22 inches

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DOC37
UHF SBGH + 2ea 36"x18" Screen Grid Refl.
4nec2 File - Includes Dimensions

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DOC38
UHF SBGH + 2ea 36"x18" Screen Grid Refl.
4nec2 File includes Summary of Dimensions

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HTML39
UHF SBGH + 2ea 36"x18" Screen Grid Refl.
EVAL *.html Performance Summary

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UHF SBGH + 2ea 36"x18" Screen Grid Refl.
Side View
[1 large square = 2.5-inches]

 
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 - davidvladd, Thu, 31 Aug 2023 12:08AM
Has anyone ever tried, (or modeled) stacking an M4 and an SBGH together? If so, does it work?
 - G, Mon, 18 Mar 2019 5:12PM