Introduction to the Gray-Hoverman TV Antenna - Page 5 - Canadian TV, Computing and Home Theatre Forums

View Poll Results: I built/will build a Gray Hoverman antenna and I am:
a tinkerer who wants the best OTA TV reception 147 65.04%
an experienced TV antenna hobbyist 13 5.75%
an electronics technician/engineer/designer/repair person 39 17.26%
an RF technician/engineer/designer 3 1.33%
a Broadcast technician/engineer/designer 3 1.33%
a HAM radio enthusiast 21 9.29%
a Home Theatre enthusiast 35 15.49%
a high technology enthusiast 39 17.26%
a computer hardware/software enthusiast 64 28.32%
a technology student 3 1.33%
new to OTA TV 44 19.47%
broke, you insensitive clod... I needed a free antenna! 46 20.35%
Multiple Choice Poll. Voters: 226. You may not vote on this poll

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post #61 of 69 (permalink) Old 2019-02-18, 09:18 PM
 
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Quote:
Originally Posted by rabbit73 View Post
Is this the design for your DBGH with L1 and L2 for CH13?

Forum member holl_ands does antenna modeling. He might be able to answer your question about how well your current DBGH will do on CH7.
You are correct, I built this model: http://www.user.dccnet.com/jonleblan...hi_Antenna.pdf
Optimized for channel 13 (L1 = 28", L2 = 10"). This would probably be called a DBGH6n2 (only 2 NARODs per bay).

NARODS on this antenna are just horizontal straight, not hat-shaped like the models at nikiml's Antenna pages. I guess therefore I cannot go by the gain sweeps shown for those models.
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post #62 of 69 (permalink) Old 2019-02-18, 11:09 PM
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Thank you for the additional information. I hope that it will be sufficient for holl_ands to answer your question.

I found it interesting that the WVNY signal is LOS because of the high elevation of the transmitting tower, but small changes in location in your area can make a considerable difference in the strength of the received signal.

You have built a very effective DBGH to receive WVNY; well done.



Best regards,
rabbit

If you can not measure it, you can not improve it.
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Last edited by rabbit73; 2019-02-18 at 11:37 PM.
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post #63 of 69 (permalink) Old 2019-02-20, 01:16 AM
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After verifying 4nec2 model dimensions (against Leblanc diagram cited above), subject DBGH6n3 [Optimizd fo Ch13] was originally posted by 300ohm [way back when] on 14Feb2009, see post #4 in fol. Thread:
https://www.digitalhome.ca/forum/186...hf-hi-uhf.html

Fol. is nikiml's EVAL RESULTS for Ch13 Optimization (L1=28-in, L2=10-in):
Note loss of Gain and also POOR SWR on Ch7....and ALSO lowest UHF Channels [fixed by nikiml Optimizations]:
Code:
Input file : C:\Python35\DBGH6n3_L1=28_L2=10_300ohm_14Feb2009.nec
Freq sweeps: [(174, 6, 8), (470, 12, 29)]e
Autosegmentation: NO

         --- Gain ---              -- Ratios -- -- Impedance --
   Freq    Raw    Net   SWR BeamW    F/R    F/B    Real    Imag  AGT  corr
==========================================================================
  174.0   6.44  -1.03 20.26  73.9  -2.36  -2.36   16.28  -94.44 1.00 -0.02
  180.0   7.37   3.66  7.25  68.2  -1.03  -1.03   41.45   -9.84 1.00 -0.02
  186.0   8.51   7.85  2.20  66.9   2.30   2.30  140.94   47.24 1.00 -0.02
  192.0   9.77   9.47  1.69  68.1   5.33   5.33  177.68   12.56 1.00 -0.02
  198.0  11.90  11.28  2.15  69.6  12.72  12.72  141.88  -35.37 0.99 -0.03
  204.0  11.57  10.83  2.31  72.4  16.23  26.27  130.18   15.36 0.99 -0.03
  210.0  11.10  10.59  2.00  74.4  11.66  12.34  153.41   40.65 0.99 -0.03
  216.0  10.66  10.25  1.86  75.9   7.99   7.99  165.24   39.14 0.99 -0.03

  470.0  14.68  11.45  6.27  41.9  13.29  13.29   57.03  129.28 1.00  0.02
  482.0  15.29  12.75  4.98  42.1  14.17  14.17  100.52  237.21 1.00  0.02
  494.0  15.71  13.91  3.80  42.0  15.47  15.47  224.53  365.45 1.00  0.02
  506.0  15.99  14.82  2.90  41.8  17.18  17.18  547.01  377.74 1.00  0.02
  518.0  16.20  15.47  2.30  41.4  19.42  19.42  685.18  -43.51 1.00  0.01
  530.0  16.34  15.85  1.97  40.8  22.34  22.34  422.12 -212.72 1.00  0.01
  542.0  16.46  16.05  1.85  40.1  25.93  25.93  266.40 -173.40 1.00  0.01
  554.0  16.56  16.14  1.87  39.1  26.49  28.14  196.04 -113.41 1.00  0.01
  566.0  16.63  16.16  1.94  38.2  23.55  26.23  163.69  -60.10 1.00  0.01
  578.0  16.62  16.12  1.99  37.4  20.36  23.99  151.60  -14.71 1.00  0.01
  590.0  16.43  15.94  1.97  37.7  17.38  23.83  153.24   21.86 1.00  0.01
  602.0  16.05  15.60  1.92  39.5  15.13  28.29  161.60   46.64 1.00  0.01
  614.0  15.70  15.26  1.90  41.4  13.72  39.78  167.79   63.48 1.00  0.01
  626.0  15.51  15.05  1.93  42.4  12.89  23.66  171.08   80.33 1.00  0.01
  638.0  15.51  15.02  1.98  42.4  12.49  18.34  176.34  102.02 1.00  0.02
  650.0  15.76  15.27  1.97  41.7  12.43  15.18  193.56  128.24 1.00  0.02
  662.0  16.08  15.71  1.81  40.9  12.53  13.03  233.68  145.19 1.00  0.02
  674.0  16.21  16.04  1.50  40.2  11.65  11.65  289.11  119.30 1.00  0.02
  686.0  16.17  16.16  1.13  38.9  11.06  11.06  295.40   36.08 1.00  0.02
  698.0  16.19  16.05  1.44  36.8  10.91  10.91  210.23  -17.10 1.01  0.04

  710.0  16.27  15.26  2.67  34.0  10.85  10.85  112.75   19.51 1.01  0.04
  722.0  15.91  12.99  5.65  30.5  11.01  11.01   59.67  103.89 1.01  0.04
  734.0  14.21   9.40 10.00  25.1  10.30  12.25   43.91  202.66 1.01  0.04
  746.0  11.23   5.83 11.76  20.7   5.85  17.43   54.86  319.35 1.01  0.04
  758.0   9.64   4.78 10.15  21.4   3.12  15.02  108.59  481.80 1.00 -0.01
  770.0  10.21   6.34  7.62  32.5   3.53   9.92  315.65  738.01 1.00 -0.01
  782.0  11.03   8.19  5.51 104.2   4.52   8.28 1138.90  747.54 1.00 -0.01
  794.0  11.45   9.47  4.06  97.8   4.85   7.67 1039.78 -415.96 1.00 -0.01
  806.0  11.83  10.48  3.14  90.2   4.86   7.49  444.59 -416.88 1.00 -0.01

Antenna Simulations, Overload Calculations, etc: http://imageevent.com/holl_ands
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post #64 of 69 (permalink) Old 2019-02-20, 01:31 AM
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Post #20 in that same Thread, 300ohm posted his 4nec2 File & Charts for Ch8-10 Optimization.

And in Post #35, I posted 4nec2 File and ANALYSIS for that Ch9 Optimization [L1=30.25-in, L2=11.5-in], also found here:
https://imageevent.com/holl_ands/grayhoverman/dbghcombo

nikiml's EVAL RESULTS for Ch9 Optimization:
Again, note Gain Loss and high SWR on lowest UHF Freqs:
Code:
Input file : C:\Python35\DBGH6n3_Ch9_L1=30-25_L2=11-5_300ohm_31Jan2009.nec
Freq sweeps: [(174, 6, 8), (470, 12, 29)]
Autosegmentation: NO

         --- Gain ---              -- Ratios -- -- Impedance --
   Freq    Raw    Net   SWR BeamW    F/R    F/B    Real    Imag  AGT  corr
==========================================================================
  174.0   8.65   7.54  2.81  67.3   4.24   4.24  117.79  -88.72 0.99 -0.06
  180.0  11.12  10.47  2.19  67.7   6.47   6.47  151.54  -85.83 0.99 -0.06
  186.0  11.60  10.17  3.25  70.4  15.40  15.40  100.89  -86.26 0.99 -0.06
  192.0  11.24   9.87  3.17  72.8  15.85  25.61   96.40  -38.02 0.99 -0.06
  198.0  10.82   9.80  2.68  74.8  11.94  13.09  112.17   -5.76 0.99 -0.06
  204.0  10.44   9.65  2.38  76.2   8.87   8.87  126.38    6.66 0.99 -0.06
  210.0  10.10   9.24  2.46  77.2   6.36   6.36  121.99   13.04 0.99 -0.06
  216.0   9.80   8.59  2.94  77.7   4.55   4.55  103.51   34.76 0.99 -0.06

  470.0  14.83  11.72  6.02  40.4  12.46  12.46   61.56  143.10 1.00  0.02
  482.0  15.40  13.03  4.69  40.3  13.19  13.19  115.55  257.80 1.00  0.02
  494.0  15.78  14.17  3.50  40.1  14.17  14.17  277.95  385.41 1.00  0.02
  506.0  15.99  15.02  2.62  39.6  15.19  15.19  635.86  280.58 1.00  0.02
  518.0  16.07  15.51  2.06  39.1  15.94  15.94  577.90 -133.34 1.00  0.02
  530.0  15.99  15.64  1.77  38.9  16.08  16.08  342.89 -181.10 1.00  0.02
  542.0  15.71  15.43  1.67  39.5  15.65  15.65  238.16 -123.69 1.00  0.02
  554.0  15.23  14.96  1.64  41.5  14.57  15.37  198.72  -68.95 1.00  0.02
  566.0  14.77  14.51  1.64  44.3  13.54  16.28  186.27  -30.69 1.00  0.02
  578.0  14.48  14.21  1.65  46.1  12.90  18.46  181.78   -6.58 1.01  0.06
  590.0  14.46  14.15  1.71  46.3  12.43  21.46  175.50   10.05 1.01  0.06
  602.0  14.67  14.28  1.83  45.5  12.30  23.19  165.91   28.64 1.01  0.06
  614.0  15.04  14.56  1.97  44.2  12.44  21.19  159.21   53.46 1.01  0.06
  626.0  15.47  14.92  2.06  42.9  12.64  18.23  160.46   82.37 1.01  0.06
  638.0  15.90  15.33  2.08  41.8  12.87  15.80  172.50  112.39 1.01  0.04
  650.0  16.21  15.71  1.99  40.9  12.92  14.04  199.79  138.94 1.01  0.04
  662.0  16.41  16.06  1.77  40.0  12.72  12.89  246.80  148.56 1.01  0.04
  674.0  16.55  16.40  1.45  38.5  12.16  12.16  301.26  112.94 1.01  0.04
  686.0  16.69  16.68  1.08  36.8  11.62  11.62  299.78   22.54 1.01  0.04
  698.0  16.88  16.70  1.50  34.7  11.16  11.16  202.48  -25.61 0.99 -0.04

  710.0  16.81  15.69  2.81  32.3  10.80  10.80  107.34   21.30 0.99 -0.04
  722.0  16.14  13.25  5.60  29.3  10.71  10.71   60.57  106.05 0.99 -0.04
  734.0  14.24   9.67  9.33  24.5  10.48  11.47   46.90  201.55 0.99 -0.04
  746.0  11.27   6.08 11.10  20.8   6.04  15.18   57.37  315.16 0.99 -0.04
  758.0   9.68   4.90  9.92  21.8   3.20  16.29  108.65  474.20 0.99 -0.03
  770.0  10.38   6.49  7.66  33.8   3.67  10.89  305.20  728.12 0.99 -0.03
  782.0  11.35   8.43  5.65 103.5   4.87   9.08 1128.86  780.57 0.99 -0.03
  794.0  11.81   9.76  4.17  95.4   5.32   8.38 1047.12 -446.70 0.99 -0.03
  806.0  12.02  10.63  3.19  87.9   5.19   7.88  429.51 -420.99 0.99 -0.03

Antenna Simulations, Overload Calculations, etc: http://imageevent.com/holl_ands

Last edited by holl_ands; 2019-02-20 at 01:52 AM.
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post #65 of 69 (permalink) Old 2019-02-20, 01:59 AM
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Subject DBGH7n3 with Ch7 Optimization [L1=31.5-in, L2=12.5-in]:

nikiml's EVAL RESULTS for Ch7 Optimization:
Significant Gain increase on Ch7, but a bit worse SWR. And again, note Gain Loss and high SWR on lowest UHF Freqs:
Code:
Input file : C:\Python35\DBGH6n3_Ch7_L1=31-5_L2=12-5_300ohm_31Jan2009.nec
Freq sweeps: [(174, 6, 8), (470, 12, 29)]
Autosegmentation: NO

         --- Gain ---              -- Ratios -- -- Impedance --
   Freq    Raw    Net   SWR BeamW    F/R    F/B    Real    Imag  AGT  corr
==========================================================================
  174.0   9.89   8.07  3.83  70.1   9.49   9.49   89.64 -109.28 0.99 -0.06
  180.0  11.52  10.08  3.27  71.4  16.12  16.12  100.73  -89.56 0.99 -0.06
  186.0  11.15   9.74  3.23  73.7  15.63  24.99   95.93  -51.38 0.99 -0.06
  192.0  10.71   9.70  2.68  75.8  11.99  13.47  112.30  -15.71 0.99 -0.06
  198.0  10.31   9.65  2.20  77.6   9.17   9.26  136.19   -0.18 0.99 -0.06
  204.0   9.96   9.39  2.07  78.8   6.74   6.74  144.71   -4.33 0.99 -0.06
  210.0   9.65   8.87  2.36  79.7   4.92   4.92  126.93   -2.43 0.99 -0.06
  216.0   9.37   8.11  3.00  80.1   3.45   3.45  100.58   23.79 0.99 -0.06

  470.0  14.77  11.68  5.97  40.7  12.11  12.11   62.08  142.85 1.01  0.02
  482.0  15.33  12.99  4.64  40.8  12.77  12.77  116.51  257.15 1.01  0.02
  494.0  15.67  14.09  3.46  40.7  13.59  13.59  279.45  382.20 1.01  0.02
  506.0  15.83  14.89  2.58  40.6  14.37  14.37  627.04  274.21 1.01  0.02
  518.0  15.80  15.27  2.02  41.0  14.89  14.89  572.82 -121.04 1.00  0.02
  530.0  15.58  15.25  1.74  42.0  15.23  15.23  351.00 -174.49 1.00  0.02
  542.0  15.30  15.03  1.65  43.2  16.04  16.04  246.55 -126.92 1.00  0.02
  554.0  15.11  14.83  1.66  43.5  16.46  17.55  199.96  -76.67 1.00  0.02
  566.0  14.95  14.65  1.69  42.9  15.21  19.40  181.39  -34.82 1.00  0.02
  578.0  14.71  14.41  1.69  42.4  13.78  21.50  177.10   -5.16 1.01  0.06
  590.0  14.59  14.27  1.73  42.4  12.72  24.19  174.37   13.21 1.01  0.06
  602.0  14.75  14.37  1.83  42.6  12.34  25.44  166.77   30.62 1.01  0.06
  614.0  15.12  14.64  1.95  42.5  12.38  22.09  160.41   54.29 1.01  0.06
  626.0  15.58  15.04  2.05  42.0  12.61  18.61  161.52   82.63 1.01  0.06
  638.0  16.00  15.45  2.06  41.5  12.95  16.23  173.69  112.42 1.01  0.05
  650.0  16.31  15.83  1.97  40.7  13.20  14.70  201.28  138.09 1.01  0.05
  662.0  16.53  16.19  1.76  39.6  13.25  13.65  247.41  146.48 1.01  0.05
  674.0  16.71  16.57  1.44  38.0  12.78  12.82  300.20  110.87 1.01  0.05
  686.0  16.87  16.87  1.08  36.1  12.09  12.09  297.33   21.45 1.01  0.05
  698.0  17.04  16.86  1.52  34.1  11.44  11.44  199.72  -24.20 0.99 -0.04

  710.0  16.87  15.75  2.83  31.9  10.93  10.93  106.82   23.99 0.99 -0.04
  722.0  16.07  13.23  5.51  28.8  10.75  10.75   61.71  107.87 0.99 -0.04
  734.0  14.10   9.65  9.06  24.2  10.49  11.48   48.45  202.22 0.99 -0.04
  746.0  11.17   6.08 10.84  20.9   5.82  15.47   58.77  315.01 0.99 -0.04
  758.0   9.67   4.93  9.81  22.4   3.01  16.62  109.63  473.40 0.99 -0.03
  770.0  10.40   6.51  7.66  35.7   3.48  10.83  304.88  727.58 0.99 -0.03
  782.0  11.34   8.41  5.67 104.6   4.66   8.95 1135.72  783.06 0.99 -0.03
  794.0  11.69   9.64  4.17  96.8   5.12   8.10 1037.55 -454.54 0.99 -0.03
  806.0  11.71  10.33  3.17  91.3   4.89   7.35  425.25 -417.20 0.99 -0.03

Antenna Simulations, Overload Calculations, etc: http://imageevent.com/holl_ands
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post #66 of 69 (permalink) Old 2019-02-20, 10:28 AM
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Quote:
Originally Posted by schoenbe View Post
You are correct, I built this model: http://www.user.dccnet.com/jonleblan...hi_Antenna.pdf
Optimized for channel 13 (L1 = 28", L2 = 10"). This would probably be called a DBGH6n2 (only 2 NARODs per bay).

NARODS on this antenna are just horizontal straight, not hat-shaped like the models at nikiml's Antenna pages. I guess therefore I cannot go by the gain sweeps shown for those models.
I don't do modeling and prefer to make on-the-air antenna comparisons. But, if I understand the results by holl_ands, your choices are to modify your present DBGH for CH7, build a second DBGH for CH7, or add a VHF antenna to your present DBGH and combine the two antennas with a UVSJ.

If you can not measure it, you can not improve it.
Lord Kelvin, 1883
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post #67 of 69 (permalink) Old 2019-05-28, 10:40 PM
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Eznec is only a tool to help make rough predictions.
Only real world construction and testing compared to a reference dipole will give you accurate gain figures.
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post #68 of 69 (permalink) Old 2019-05-30, 07:47 AM
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Haven't seen anyone using or discussing EZNEC here.
Zank Frappa likes this.

DB8E/VHF Yagi rotor FM Bandstop ap-8700 preamp 8way split LG lcd.
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post #69 of 69 (permalink) Old 2019-09-27, 07:12 PM
 
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Continuing with the reflector grid idea, based on nikiml's GH10: nikiml's Antenna pages - GH10 UHF antenna , based on holl_ands' screen grid reflector: UHF SBGH + 2ea 36"x18" Screen Grid Refl. , based on Yurii Pylypenko's continuous reflector: https://ypylypenko.livejournal.com/82831.html




SBGH (AWG10 elements) with 36x48" continuous reflector grid (2x2" AWG16): Raw Gain 13.3 to 15.5 to 14.1, SWR max 2.3
2xGH (AWG10 elements) with 64x48" continuous reflector grid (2x2" AWG16): Raw Gain 15.9 to 17.9 to 16.3, SWR max 2.3
3xGH (AWG10 elements) with 92x48" continuous reflector grid (2x2" AWG16): Raw Gain 17.5 to 19.6 to 17.7, SWR max 2.3
4xGH (AWG10 elements) with 120x48" continuous reflector grid (2x2" AWG16): Raw Gain 18.6 to 20.7 to 18.9, SWR max 2.3

nec files: https://ln2.sync.com/dl/5d729e850/pq...i6x46-gwr5ytw2
For measurements, copy/paste nec file text into nikiml's nec viewer nikiml's Antenna pages - Nec Viewer

Decreasing the spacing between the reflector's horizontal lines from 2" to 1" or 0.5" will increase gain and F/B ratio, and slightly increase SWR a bit:



A thicker gauge wire for reflector will also increase gain and F/B ratio a bit while keeping the SWR the same:


36' 8200U-KT200-HDHR#1067A7DF / 33' DB8e-CM7777-HDHR#1067A183
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