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 holl_ands | Home > Multi-Bay Bowtie Antennas > UHF 4-Bay Bowties with Reflector > 
UHF Free-Form 4-Bay + DblAnglRefl
UHF Free-Form 4-Bay (FF4) Bowtie Antennas with various sized Variable Double Angle Reflectors (VDAR)
analyzed using 4nec2.  Essentially ALL dimensions were Optimized using nikiml's Python Scripts,
including the Angle of the Reflector's outer "wings".

Pictures of finished FF4's:
http://www.avsforum.com/forum/25-hdtv-technical/2483921-northeast-connecticut-mansfield-trees-trees-trees.html#post44801233

a) FF4 + Reflector = 40"x36" (unfolded), same as mclapp's M4 for backfits & comparison purposes,
but Reflector is Swept Forward 4.375-in vice 2.5-in.  Elements and Feedline are AWG10.

When I changed to AWG8 (w/o reoptimizing), FF4 Gain = 14.3 to 15.3 to 14.8 to 15.6 dBi,
with Gain on 470 MHz increasing 0.3 dB, but only 0.1 dB on other freqs.
Compare to M4 (10.0"x9.5") Gain =  13.8 to 15.8 to 15.0 dBi and M4 (9.5"x9.0") Gain = 13.3 to 16.0 dBi.
So FF4 Gain increased as much as 1 dB on 470 MHz, with higher Gain on low to mid-band channels
and about the same on the higher channels, with somewhat lower F/B & F/R Ratios (probably
needs a larger Reflector) and same High Gain in Hi-VHF Band:

UHF FF4 Raw Gain = 15.1 dBi +/- 0.4 dB, dropping to 14.0 dBi on 470 MHz, F/B & F/R Ratio Min = 14.8 dB
[GOOD] and SWR (300-ohms) under 1.8.
Hi-VHF Raw Gain = 8.1 dBi, F/B & F/R Ratio Min = 19 dB [EXCL] and SWR = 16.8 to 15.7 [Excessive].

SUMMARY OF DIMENSIONS FROM 4nec2 FILE (In inches, rounded to nearest 1/8-in):
Rbow=0.051            ' Radius of Bowtie Elements (AWG10, not critical)
Rfeed=0.051           ' Radius of Feedlines (cAWG10, not critical)
Hop=1.0              ' X-Coord Separation of Feedlines at Crossover
ZBowII=12.0    ' From Center of INNER Bowtie to Center of INNER Bowtie, Optimizer found 11.99499
ZBowOI=11.0    ' From Center of INNER Bowtie to Center of OUTER Bowtie, Optimizer found 10.91547
BowLeni=11.5    ' INNER Bow Whisker Length (lose some in bend), Optimizer found 11.59459
BowLeno=12.0    ' OUTER Bow Whisker Length (lose some in bend), Optimizer found 11.95864
BSi=1.5            ' INNER Bow Forward Sweep distance at tip of the Whisker, Optimizer found 1.557153
BSo=5.75          ' OUTER Bow Forward Sweep distance at tip of the Whisker, Optimizer found 5.78872
TineSepi=7.375    ' INNER Bow Tine Separation, Optimizer found 7.344971
TineSepo=6.5    ' OUTER Bow Tine Separation, Optimizer found 6.513835
FS=1.75            ' Separation between two FEEDLINE wires, Optimizer found 1.773704
ZCross=2.625      ' From Center of Feedline Cross-Over to Center of OUTER Bowtie, Optimizer found 2.68731

##################################################################
b) FF4 + TALLER Reflector = 48"x36" unfolded), Reflector is Swept Forward 3.375-in vice 2.5-in.
Elements and Feedline are AWG10.  Outer Bowties are now much smaller, at SAME Angle as Inner.
Raw Gain increased 0.3 dB on 470 MHz,  1.6 dB more on 698 MHz and eliminated the mid-Band Gain Dip
found in the above AWG10 40x36-in Reflector.

UHF Raw Gain = 14.6 (470 MHz) to 16.2 (674 MHz) peaking at 17.1 dBi (698 MHz),
UHF F/B & F/R Ratio Min = 14.8 dB [GOOD] and SWR (300-ohms) under 2.1.
Hi-VHF Raw Gain = 10.8 to 8.3 dBi, F/B & F/R Ratio Min = 10.9 dB [FAIR] and SWR (300-ohms) = 34 to 23 (Excessive).

SUMMARY OF DIMENSIONS FROM 4nec2 FILE (In inches, rounded to nearest 1/8-in):
Rbow=0.051        ' Radius of Bowtie Wires (AWG10, not critical)
Rfeed=0.051       ' Radius of Feedline Wires (AWG10, not critical)
Hop=1.0              ' Wire Separation at the Feedline Crossover
ZBowII=12.0        ' From Center of INNER bowtie to Center of INNER Bowtie, Optimizer found 11.99729
ZBowOI=10.675     ' From Center of INNER Bowtie to Center of OUTER Bowtie, Optimizer found 10.67465
BowLeni=12.875     ' INNER Bow Whisker Length (lose some in bend), Optimizer found 12.86343
BowLeno=8.125     ' OUTER Bow Whisker Length (lose some in bend), Optimizer found 8.124315
BSi=3.5            ' INNER Bow Forward Sweep distance at tip of the Whisker, Optimizer found 3.496068
BSo=2.25          ' OUTER Bow Forward Sweep distance at tip of the Whisker, Optimizer found 2.273594
TineSepi=6.75     ' INNER Bow Tine Separation, Optimizer found 6.813349
TineSepo=3.875     ' OUTER Bow Tine Separation, Optimizer found 3.875966
FS=2.875            ' Separation between two FEEDLINE wires, Optimizer found 2.82885
ZCross=2.375       ' From Center of Feedline Cross-Over to Center of OUTER Bowtie, Optimizer found 2.406892

##################################################################
c) FF4 with a TALLER and WIDER Reflector alternative is T.B.D.

EDIT (23Mar2016): Added Dimensioned Drawing for Bowtie portion of FF4+VDAR(48x36)
version (b) and replaced associated 4nec2 File with embedded CMD--OPT and CMD--EVAL Commands
(vice original *.bat text File).
Date(s): 2 Nov 2013. Album by holl_ands. 1 - 54 of 54 Total. 11483 Visits.
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1
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 40-in H x 36-in W
3D View


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2
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 40-in H x 36-in W
Front View
[1 large square = 5-inches]
Probably needs a TALLER Reflector.


Enlarge photo 3
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3
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 40-in H x 36-in W
Top View
[1 large square = 2.5-inches]


Enlarge photo 4
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4
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 40-in H x 36-in W
Side View
[1 large square = 5-inches]


Enlarge Microsoft Word Document 5
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DOC5
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 40-in H x 36-in W
4nec2 File


Enlarge Microsoft Word Document 6
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DOC6
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 40-in H x 36-in W
Contents of Python Control *.bat File


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7
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 40-in H x 36-in W
UHF Raw Gain = 15.1 dBi +/- 0.4 dB,
dropping to 14.1 dBi on 470 MHz


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8
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 40-in H x 36-in W
UHF SWR (300-ohms) Under 1.8

Note MIN at 470 MHz, unlike most 4-Bay's


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UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 40-in H x 36-in W
UHF Impedance


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10
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 40-in H x 36-in W
Azimuthal Pattern at 470 MHz


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11
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 40-in H x 36-in W
Azimuthal Pattern at 530 MHz


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12
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 40-in H x 36-in W
Azimuthal Pattern at 590 MHz


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13
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 40-in H x 36-in W
Azimuthal Pattern at 650 MHz


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14
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 40-in H x 36-in W
Azimuthal Pattern at 698 MHz


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15
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 40-in H x 36-in W
Azimuthal Pattern at 806 MHz


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16
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 40-in H x 36-in W
Elevation Pattern at 470 MHz


Enlarge photo 17
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17
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 40-in H x 36-in W
Elevation Pattern at 530 MHz


Enlarge photo 18
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18
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 40-in H x 36-in W
Elevation Pattern at 590 MHz


Enlarge photo 19
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19
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 40-in H x 36-in W
Elevation Pattern at 650 MHz


Enlarge photo 20
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20
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 40-in H x 36-in W
Elevation Pattern at 698 MHz


Enlarge photo 21
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21
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 40-in H x 36-in W
Elevation Pattern at 806 MHz


Enlarge photo 22
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22
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 40-in H x 36-in W
Hi-VHF Raw Gain = 8.1 dBi
Hi-VHF F/B & F/R Ratio Min = 19 dB


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23
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 40-in H x 36-in W
Hi-VHF SWR (300-ohm) = 16.8 to 15.7


Enlarge photo 24
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24
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 40-in H x 36-in W
Hi-VHF Impedance


Enlarge photo 25
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25
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 40-in H x 36-in W
Azimuthal Pattern at 174 MHz


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26
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 40-in H x 36-in W
Azimuthal Pattern at 198 MHz


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27
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 40-in H x 36-in W
Azimuthal Pattern at 216 MHz


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28
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 48-in H x 36-in W
3D View


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29
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 48-in H x 36-in W
Front View
[1 large square = 5-inches]
Probably needs a WIDER Reflector.


Enlarge photo 30
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30
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 48-in H x 36-in W
Top View
[1 large square = 2.5-inches]


Enlarge Microsoft Word Document 31
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DOC31
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 48-in H x 36-in W
4nec2 File


Enlarge photo 32
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32
UHF Free-Form 4-Bay [Just the Bowties]
FLAT View [Prior to Bowtie Forward Sweep]
[1 large square = 5-inches]

"[1 large square = 2.5-inches]"
"The top measure line that both the Z..."
View Comments...

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33
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 48-in H x 36-in W
Side View
[1 large square = 5-inches]


Enlarge photo 34
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34
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 48-in H x 36-in W
UHF Raw Gain = 14.6 (470 MHz) to 16.2
(674 MHz) peaking at 17.1 dBi (698 MHz).
UHF F/B & F/R Ratio Min = 14.8 dB.


Enlarge photo 35
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35
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 48-in H x 36-in W
UHF SWR (300-ohm) Under 2.1


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36
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 48-in H x 36-in W
UHF Impedance


Enlarge photo 37
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37
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 48-in H x 36-in W
Azimuthal Pattern at 470 MHz


Enlarge photo 38
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38
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 48-in H x 36-in W
Azimuthal Pattern at 530 MHz


Enlarge photo 39
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39
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 48-in H x 36-in W
Azimuthal Pattern at 590 MHz


Enlarge photo 40
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40
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 48-in H x 36-in W
Azimuthal Pattern at 650 MHz


Enlarge photo 41
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41
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 48-in H x 36-in W
Azimuthal Pattern at 698 MHz


Enlarge photo 42
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42
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 48-in H x 36-in W
Azimuthal Pattern at 806 MHz


Enlarge photo 43
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43
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 48-in H x 36-in W
Elevation Pattern at 470 MHz


Enlarge photo 44
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44
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 48-in H x 36-in W
Elevation Pattern at 530 MHz


Enlarge photo 45
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45
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 48-in H x 36-in W
Elevation Pattern at 590 MHz


Enlarge photo 46
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46
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 48-in H x 36-in W
Elevation Pattern at 650 MHz


Enlarge photo 47
enlarge 298KB, 1024x1024
47
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 48-in H x 36-in W
Elevation Pattern at 698 MHz


Enlarge photo 48
enlarge 293KB, 1024x1024
48
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 48-in H x 36-in W
Elevation Pattern at 806 MHz


Enlarge photo 49
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49
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 48-in H x 36-in W
Hi-VHF Raw Gain = 10.8 to 8.3 dBi
Hi-VHF F/B & F/R Ratio Min = 10.9 dB


Enlarge photo 50
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50
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 48-in H x 36-in W
Hi-VHF SWR (300-ohms) = 34 to 23 is EXCESSIVE


Enlarge photo 51
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51
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 48-in H x 36-in W
Hi-VHF Impedance


Enlarge photo 52
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52
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 48-in H x 36-in W
Azimuthal Pattern at 174 MHz


Enlarge photo 53
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UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 48-in H x 36-in W
Azimuthal Pattern at 198 MHz


Enlarge photo 54
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54
UHF Free-Form 4-Bay + DblAnglRefl - OPT
Double Angle Reflector = 48-in H x 36-in W
Azimuthal Pattern at 216 MHz


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Very interesting, love to see an 8 bay version.
 - 
Robert, Mon, 4 Nov 2013 5:02PM