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One more,
Tine separation - 7"
How far is the reflector behind the bow ties?
How did you derive the dimensions?
I like the build. Have you modeled it, optimized it?
I have a model of it with no reflector it gets 8.6 dBi average net gain from 14 to 35, the SWR is higher than the 2.7 recommenced on the top few channels but the reflector may help that. (as well as giving the ~3 dB boost).
Do you have any VHF stations?
 

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Discussion Starter #6
How far is the reflector behind the bow ties?
How did you derive the dimensions?
I like the build. Have you modeled it, optimized it?
I have a model of it with no reflector it gets 8.6 dBi average net gain from 14 to 35, the SWR is higher than the 2.7 recommenced on the top few channels but the reflector may help that. (as well as giving the ~3 dB boost).
Do you have any VHF stations?
Hi, the reflector is set at 5.5". I started at 4" and adjusted the bolts to a final 5.5" gives the best reception.
It's off the cuff. I was having trouble with rf 16 so, 482MHz ( wavelength = c/f ) converted to inches = 24.48 in., a half wave element is about 12.24 in. That puts the width of 1 bay including the phase line separation at 25.75" or a full wavelength. This worked and is useful for all of the UHF frequencies currently in use for tv. I have had no issues since this went up, I now have two, pointed in different directions.
I don't do the modeling I was thinking someone here may want to take a shot. If you would like to model it or just learn more CLICK HERE
No matter what the modeling says this solved a problem I couldn't fix with a hoverman or a 4 bay 9.5 x 9 bowtie.
The larger elements do the trick on the lower frequencies.
Oh, I don't have vhf in the area or anywhere around central florida. Wish I had at least one so I could test for it.
Thanks
 

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Well as I said I already have a model it just needed a reflector and the AGT adjusted for the new dimensions.
It's one of holl_ends models from the same series as the ff6 that the website you pointed to credited. I think Mike was the original author of this model but I haven't a clue where "mikes blog" is maybe mike is ' old sparks" I can't remember where I found this model.
I had to remove a couple line that were "over laid"
I don't agree with the site you pointed to in one regard and that is how close reflector wires need to be. He states 2 X 3 inches is to large but 2 inchs is completely adequate to block/reflect TV frequency radio waves even when they extended to 700 MHz.
And the three inch for verticle wires is completly irrelevant because there is no vertical polarized component here, it's all horizontal polarized so vertical wires are literally invisible to it.
I put 1/2 X 1 inch panel as the reflector to match the reflector you used.
I'm sure structurally smaller openings are better and may be the reasoning used by the sites author.
I'm surprised that other antennas couldn't get channel 16 considering this antennas rather modest ~12 dBi gain a decent gh should have as good or better gain.
What kind of hoverman was it commercial or homebrew?
i have a commercial double hoverman that does quite well even though it's design was for predigital spectrum.
Here is the results from the model:
Code:
Frequency    Raw Gain    Zr    Zi    match loss    Net Gain    Channel    SWR
473    12.25    203.002    137.897    -0.4164857755    11.8335142245    14    1.9553006424
479    12.35    215.943    152.766    -0.481801387    11.868198613    15    1.9587861554
485    12.45    231.256    167.564    -0.4852239982    11.9647760018    16    1.9635477472
491    12.54    249.408    182.095    -0.4896321458    12.0503678542    17    1.9696740662
497    12.64    270.845    196.018    -0.4954168844    12.1445831156    18    1.9777029327
503    12.73    296.201    208.814    -0.5026925532    12.2273074468    19    1.987784592
509    12.82    326.073    219.711    -0.5119373505    12.3080626495    20    2.0005693461
515    12.91    361.104    227.541    -0.5234733147    12.3865266853    21    2.0164847033
521    12.99    401.82    230.58    -0.5375584062    12.4524415938    22    2.0358635925
527    13.07    448.339    226.466    -0.5546528683    12.5153471317    23    2.0593104657
533    13.16    499.854    212.244    -0.5754817234    12.5845182766    24    2.0877826856
539    13.23    554.033    184.173    -0.5997386465    12.6302613535    25    2.1208230623
545    13.31    606.546    138.998    -0.6282644354    12.6817355646    26    2.159539616
551    13.38    650.103    75.2447    -0.6609337843    12.7190662157    27    2.2037291572
557    13.44    676.271    -4.40708    -0.6984761728    12.7415238272    28    2.2543558525
563    13.5    677.885    -92.5959    -0.7411491227    12.7588508773    29    2.3117591374
569    13.56    652.499    -178.21    -0.7891057731    12.7708942269    30    2.3761628067
575    13.62    604.04    -250.564    -0.8427058766    12.7772941234    31    2.4481003739
581    13.66    541.32    -302.617    -0.9012686409    12.7587313591    32    2.5267470401
587    13.71    473.478    -333.863    -0.9661377651    12.7438622349    33    2.6140411686
593    13.75    408.038    -346.732    -1.0358784857    12.7141215143    34    2.70823079
599    13.78    348.891    -346.038    -1.1116713781    12.6683286219    35    2.8111372584
605    13.81    297.917    -335.982    -1.1918029578    12.6181970422    36    2.9207001703
                            
                            
                            
max    13.81            max    12.7772941234        2.9207001703
min    12.25            min    11.8335142245        1.9553006424
                            
Average     13.1591304348            Average    12.4747178502        2.2377449288
Here is the model you don't need to "do modeling" to run or play with others models
The diameters oft he wires my not be in line with your antenna but it wont change the results very much.
Code:
CM Mike's Blog V10 Vertical 10-Bay, BowSwp=0.0-in with NO Refl, 4nec2 by holl_ands, 31Mar2015
CM BowLength=7.0-in, BowSpacing=7.0-in, TineSep=3.0-in (AWG6 Elements), Hop=0.75-in.
CM FeedSep=1.0-in (AWG14), ZCross=3.5-in.  AUTOSEG(7), NO Errors or Warnings, AGT=1.0.
CM FEEDLINE CROSSOVERS MISSING BETWEEN OTHER EVERY SET OF BOWTIES.
CE
' SOURCE wire Radius. Adjust for AGT=1.0: UHF=0.0315 & HiVHF=0.045
SY Rsrc=0.0495
SY Rbow=0.081        ' Radius (in inches) of BOWTIE elements
SY Rfeed=0.032        ' Radius (in inches) of FEEDLINE wires
' Distance between the centers of the two INNER and INNER-OUTER bowties:
SY ZBowII=15.0
SY ZBowOI=ZBowII
SY BaySep=ZBowII+ZBowOI    ' Center-to-Center Separation between Upper & Lower 4-Bay
' Bow Half-Length (lose some in bend) - Assume all SAME:
SY BowLen=12.0
SY BowSwp=0.0        ' Bow Forward Sweep distance at tip of the whisker
' INNER Bow Tine Separation - Assume all SAME:
SY TineSepInr=7.0
SY TineSepOut=TineSepInr ' OUTER Bow Tine Separation - Assume all SAME
' Separation between two FEEDLINE wires:
SY FeedSep=1.0
' From center of Feedline Cross-Over to center of OUTER bowtie
SY ZCross=3.5
SY Cond=3.0e7        ' Conductivity (Copper=3.0e7, Alum=2.0e7, StainlessSteel=1.67e7)
SY Hop=1.0        ' Separation at Crossover
SY RS=5.5        ' Separation between Reflector and Bowties: reflector added by ghz24
SY RH=34    'Reflector Height
SY RW=24    'Reflector Width
SY VS=68    ' !! MUST BE EVEN INTEGER !!
SY HS=18    '!! MUST BE EVEN INTEGER !!
'
' Calculated from above INPUT Values:
SY ZBowInr=ZBowII/2        ' Distance from antenna center to center of INNER bowtie
SY ZBowOut=ZBowII/2+ZBowOI    ' Distance from antenna center to center of OUTER bowtie
SY Z1=ZBowOut+TineSepOut/2
SY Z2=ZBowOut
SY Z3=ZBowOut-TineSepOut/2
SY Z4=ZBowOut-ZCross+0.875
SY Z5=ZBowOut-ZCross
SY Z6=ZBowOut-ZCross-0.875
SY Z7=ZBowInr+TineSepInr/2
SY Z8=ZBowInr
SY Z9=ZBowInr-TineSepInr/2
SY Z11=BaySep+ZBowOut+TineSepOut/2
SY Z12=BaySep+ZBowOut
SY Z13=BaySep+ZBowOut-TineSepOut/2
SY Z14=BaySep+ZBowOut-ZCross+0.875
SY Z15=BaySep+ZBowOut-ZCross
SY Z16=BaySep+ZBowOut-ZCross-0.875
SY Z17=BaySep+ZBowInr+TineSepInr/2
SY Z18=BaySep+ZBowInr
SY Z19=BaySep+ZBowInr-TineSepInr/2
'
SY Z21=Z18+BaySep+TineSepOut/2
SY Z22=Z18+BaySep
SY Z23=Z18+BaySep-TineSepOut/2
SY Z27=Z18-ZCross-0.875
SY Z28=Z18-ZCross
SY Z29=Z18-ZCross+0.875
SY YBowInr=FeedSep/2+(BowLen^2-(TineSepInr/2)^2-BowSwp^2)^0.5    ' Ymax for Inner Bowties
SY YBowOut=FeedSep/2+(BowLen^2-(TineSepOut/2)^2-BowSwp^2)^0.5    ' Ymax for Outer Bowties
SY RHz=RH/2
SY RWy=RW/2
SY VSz=VS/2
SY HSy=HS/2
'
'  #    segs    X1      Y1        Z1     X2        Y2         Z2    radius
'   Next 3 cards are the reflector add by ghz24
SM    VSz    HSy    0    0    RHz    0
SC    0    0    0    RWy    0
GX    400    011
' SIMULATED SOURCE WIRE:
GW  1     1    RS    -FeedSep/2    0.0     RS       FeedSep/2    0.0    Rsrc
' LOWER 4-BAY:
' INNER BOWTIES:
GW  2     5   BowSwp+RS     YBowInr      Z7     RS       FeedSep/2     Z8    Rbow
GW  3     5   BowSwp+RS     YBowInr      Z9     RS       FeedSep/2     Z8    Rbow
GW  4     5    RS    -FeedSep/2    Z8      BowSwp+RS   -YBowInr     Z7    Rbow
GW  5     5    RS    -FeedSep/2    Z8      BowSwp+RS   -YBowInr     Z9    Rbow
GW  6     5   BowSwp+RS     YBowInr     -Z7     RS       FeedSep/2    -Z8    Rbow
GW  7     5   BowSwp+RS     YBowInr     -Z9     RS       FeedSep/2    -Z8    Rbow
GW  8     5    RS    -FeedSep/2   -Z8      BowSwp+RS   -YBowInr    -Z7    Rbow
GW  9     5    RS    -FeedSep/2   -Z8      BowSwp+RS   -YBowInr    -Z9    Rbow
' MIDDLE BOWTIES:
' OUTER BOWTIES:
'
' CROSS-OVER FEEDLINE:
GW 34     3    RS     FeedSep/2    Z8     RS       FeedSep/2     0.0    Rfeed
GW 35     3    RS    -FeedSep/2    Z8     RS      -FeedSep/2     0.0    Rfeed
GW 36     3    RS     FeedSep/2   -Z8     RS       FeedSep/2     0.0    Rfeed
GW 37     3     RS    -FeedSep/2   -Z8     RS      -FeedSep/2     0.0    Rfeed
'
' INNER BOWTIES:
' MIDDLE BOWTIES:
'
' CROSS-OVER FEEDLINE:
'
' MOD: NO CROSSOVER:
'
' WITH CROSSOVER:
' GW 70     3    RS     FeedSep/2    Z18     RS       FeedSep/2     Z22    Rfeed
' GW 71     3    RS    -FeedSep/2    Z18     RS      -FeedSep/2     Z22    Rfeed
' GW 72     1    RS    -FeedSep/2    Z20     -Hop/2+RS    0.0         Z21    Rfeed ' Left
' GW 73     1    RS     FeedSep/2    Z22     -Hop/2+RS    0.0         Z21    Rfeed ' Hand
' GW 74     1    RS     FeedSep/2    Z20      Hop/2+RS    0.0         Z21    Rfeed ' Rot.
' GW 75     1    RS    -FeedSep/2    Z22      Hop/2+RS    0.0         Z21    Rfeed ' Rule
' GW 76     3    RS     FeedSep/2    Z20     RS       FeedSep/2     Z2    Rfeed
' GW 77     3    RS    -FeedSep/2    Z20     RS      -FeedSep/2     Z2    Rfeed
'
' MOD: NO CROSSOVER:
'
' WITH CROSSOVER:
' GW 78     3    RS     FeedSep/2   -Z18     RS       FeedSep/2    -Z22    Rfeed
' GW 79     3    RS    -FeedSep/2   -Z18     RS      -FeedSep/2    -Z22    Rfeed
' GW 80     1    RS    -FeedSep/2   -Z20     -Hop/2+RS    0.0        -Z21    Rfeed ' Left
' GW 81     1    RS     FeedSep/2   -Z22     -Hop/2+RS    0.0        -Z21    Rfeed ' Hand
' GW 82     1    RS     FeedSep/2   -Z20      Hop/2+RS    0.0        -Z21    Rfeed ' Rot.
' GW 83     1    RS    -FeedSep/2   -Z22      Hop/2+RS    0.0        -Z21    Rfeed ' Rule
' GW 84     3    RS     FeedSep/2   -Z20     RS       FeedSep/2    -Z2    Rfeed
' GW 85     3    RS    -FeedSep/2   -Z20     RS      -FeedSep/2    -Z2    Rfeed
'
GS    0     0    0.0254    ' CONVERT ABOVE FROM INCHES TO METERS FOR NEC.
GE    0            ' No Ground Plane
GN    -1            ' Free Space
EK 0                ' Enable Extended Kernel
LD 5 0 0 0 Cond 0        ' Conductivity
'
EX 0 1 1 0 1 0            ' Simulated SOURCE on GW1
'
' FR Freq Sweep choices in order of increasing calculation time (fm holl_ands):
' FR 0 0 0 0 470 0        ' Fixed Freq
' FR 0 5 0 0 470 76        ' Freq Sweep 470-698 every 76 MHz - SPECIAL FOR Hi-Rez Beamwidth
' FR 0 29 0 0 470 12        ' Freq Sweep 470-806 every 12 MHz - OLD UHF BAND
' FR 0 34 0 0 410 12        ' Freq Sweep 410-806 every 12 MHz - Even Wider Sweep
FR 0 39 0 0 470 6        ' Freq Sweep 470-698 every 6 MHz - PREFERRED FOR UHF
' FR 0 77 0 0 470 3        ' Freq Sweep 470-698 every 3 MHz
' FR 0 153 0 0 470 1.5        ' Freq Sweep 470-698 every 1.5 MHz
' FR 0 71 0 0 300 10        ' Freq Sweep 300RS000 every 10 MHz - WIDEBAND SWEEP
' FR Hi-VHF choices:
' FR 0 15 0 0 174 3        ' Freq Sweep 174-216 every 3 MHz
' FR 0 29 0 0 174 1.5        ' Freq Sweep 174-216 every 1.5 MHz - PREFERRED
' FR 0 45 0 0 162 1.5        ' Freq Sweep 162-228 every 1.5 MHz - Add +/- 12 MHz BW
' FR 0 27 0 0 189 1.5        ' Freq Sweep 186-228 every 1.5 MHz - SPECIAL
' FR 0 43 0 0 174 1        ' Freq Sweep 174-216 every 1 MHz - Hi-Rez
' FR 0 23 0 0 198 1        ' Freq Sweep 198-220 every 1 MHz - Hi-Rez - Ch13 SPECIAL
' FR 0 26 0 0 150 6        ' Freq Sweep 150-300 every 6 MHz - WIDEBAND SWEEP
' FR Lo-VHF choices:
' FR 0 19 0 0 54 3        ' Frequency Sweep every 3 MHz for Ch2-6 + FM
' FR 0 35 0 0 54 1        ' Frequency Sweep every 1 MHz for Ch2-6
' FR 0 36 0 0 75 1        ' Frequency Sweep every 1 MHz for Ch5 + Ch6 + FM
' FR 0 28 0 0 54 6        ' Wide Freq Sweep every 6 MHz for Ch2RS3
' FR 0 64 0 0 54 12        ' Super Wide Freq Sweep 54-810 every 12 MHz
' RP choices in order of increasing calculation time:
' RP 0 1 1 1510 90 90 1 1 0 0    ' 1D Gain toward 0-deg Azimuth - SIDE GAIN
' RP 0 1 1 1510 90 0 1 1 0 0    ' 1D Gain toward 90-deg Azimuth - FORWARD GAIN
' RP 0 1 1 1510 90 180 1 1 0 0    ' 1D Gain toward 270-deg Azimuth - REVERSE GAIN
' RP 0 1 37 1510 90 0 1 5 0 0     ' 2D (Left only) Azimuthal Gain Slice
RP 0 1 73 1510 90 0 1 5 0 0    ' 2D Azimuthal Gain Slice - PREFERRED
' RP 0 1 361 1510 90 0 1 1 0 0    ' 2D Azimuthal Gain Slice - Hi-Rez 1-deg for Beamwidth
' RP 0 73 1 1510 90 0 5 1 0 0     ' 2D Elevation Gain Slice
' RP 0 73 73 1510 90 0 5 5 0 0     ' 3D Lower Hemisphere reveals antenna (Fixed Freq)
' RP 0 285 73 1510 90 0 5 5 0 0    ' 3D Full Coverage obscures antenna (Fixed Freq)
 

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Discussion Starter #8 (Edited)
When I indicated that I was having issues with the lower frequencies with the Hoverman or 4 bay bowtie (my builds) I should have expanded the issue. I wasn't experiencing typical interference as from moving tree limbs, weather, or any of the common problems. This was a perfect picture that appeared to be skipping slightly yet often enough to be annoying. A friend said it was as if a video player was dropping frames. I also have read about issues with lower frequencies since the repack from others.
This led me to focus on those channels and the antenna above is the result.
While constructing this build I had a vision of holl_ands free form 4 bay antennas in mind. I thought I would need to add two of the proven 9.5" bows to balance the high and low frequencies. Turns out I didn't need the smaller bows. The two 12.5" bays worked fine. My channels are, 16, 19, 21 and 31, a nice spread.
All channels came in fine and the annoying skipping was gone.
The 12 X 15 is simple to build and the reflector increases the stability and gain, win, win.
I cannot ethically pick and choose sections of modeling from another antenna build and claim it states how this antenna is functioning.
I have had great results with the 0.5" X 1.0" reflector material I mentioned on my web site. I have experimented with many sizes of material and the larger grids performed somewhat miserable due to their lack of stiffness in the wind or even light breezes.
Should you like to model this antenna for its own merits, feel free to do so.
All the information is on my site here,
Cosmic Antenna
 

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I have/did model it, I posted the results and the model, despite a few minor differences I am confident of its accuracy.
I have/did model it, I posted the results and the model, despite a few minor differences I am confident of its accuracy.

cannot ethically pick and choose sections of modeling from another antenna build and claim it states how this antenna is functioning.
I think you may have misunderstood how this model works the original author built it with variables so it can be quickly altered in an almost infinite number of variations.
They are declared with the lines that start with "SY"
Even though the original model had 7" whiskers spaced 9" apart with a tine separation of 3", I only had to change three numbers to make it a 12" whisker separated by 15" with a tine spread of 7" (just like yours)
This was the first result I posted without a reflector,
These were the variables plus one for reflector separation(after I added it) that I let the optimizer have to play with.
It showed your dimensions seem very well optimized for the frequency you were going for,I ran it through the optimizer
it didn't change any of the dimensions enough to measure with the tools we would use to fabricate the antenna, and even if it was fabricated to micrometer specs the difference in performance would be unmeasurable without very expensive equipment.
Also the gain is comparable to the posted gain for this type of antenna when frequency differences are considered.
 

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Discussion Starter #10
GHZ24,
I wrote a reply agreeing with you on the modeling, I have no idea why it didn't post.
I don't use the software, I'm outside building and experimenting but I have learned how to read the results and your amended results agree with the results I'm getting from the antenna.

Hopefully this will help some who are having lower uhf issues .
 

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Discussion Starter #12
While this 12"x15" bowtie worked well at my location, I believe that the FF4 Bowtie by holl_ands would be a great choice for many locations. The ff4 has elements optimized for the entire uhf band.
 
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