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Best NEW Spectrum antennas?

7K views 19 replies 10 participants last post by  jop 
#1 · (Edited)
Hello,
I am wondering what would be a good post-spectrum antenna, either a pure UHF, or combo UHF VHF-Hi?, for long distance (60-80 miles)
I can make or buy one. Is the CM4228HD the best antenna to buy for the new spectrum, or would the Winegard HD8800 UHF be better, or the DB8e?

I havent really seen any comparisons between these three TV antennas? And not much spoken about the new spectrum effects?

(I dont mind hacking a 4228 if its an easy hack and makes a real difference)

Or, maybe there is a simple to build antenna with a high gain 15+ DBa that works well on the new spectrum?
Sincerely,
Schoolbus
 
#2 ·
#4 ·
The FF6 is difficult. Coming up with the angles on the reflector and bending things to the correct degree is painful. I built an FF4 before.
I'd rather build this one below, its simpler, but optimized for the new spectrum and maybe with solid triangles,(?), which I hear are better, and stronger:
https://imageevent.com/holl_ands/multibay/4bayrefl/newuhffreeform4bayscreenreflopt.

Curious, if the side lobes could be merged in the with main lobe, would that improve forward gain? Side lobes seem to be a waste.

I was also thinking of a fat dipole antenna like one of the ones on this link (below) only optimized for the new spectrum.


I just want a simple to build 15++ dbi antenna. For the new spectrum. Or one I could buy maybe.
Schoolbus
 
#10 ·
Curious, if the side lobes could be merged in the with main lobe, would that improve forward gain? Side lobes seem to be a waste.
Might be a waste for you, but not necessarily for everyone. Every person's specific situation is different. A single narrow main beam might not be desirable. Especially for someone who just wants to put up an antenna and not spend hours trying to find a magic sweet spot, only to find it changes two days later under different weather conditions. Yes there are always tradeoffs.
 
#5 · (Edited)
Hello,
I am wondering what would be a good post-spectrum antenna, either a pure UHF, or combo UHF VHF-Hi?,
(I dont mind hacking a 4228 if its an easy hack and makes a real difference)
Hacking a 4228HD for the low end of UHF could be done, but it wouldn't be easy. You would have to increase the length of the whiskers and increase the vertical spacing between the bays to about 10.5 or 11 inches.

There is a Yagi made in the UK that has increased gain at the low end of UHF, which is the XB 16A, an A-Group Aerial.



Gain is in dBd, add 2.15 for dBi.

Their A-Band is 21 to 37, which is about the same as our 14 to 37 because their channels are wider.

https://www.aerialsandtv.com/atvstockaerialtests.html#Agroup

https://www.aerialsandtv.com/onlineaerials.html#XB16s

Item:
XB16A Aerial
Price: £62.00
 
#6 · (Edited)
Fol. Comparison Chart shows A-D Modeling Results for DB-8e [specs say it IGNORES the 2-Way Combiner Loss] vs my 4nec2 Modeling Results for CM4228HD with HHH Mod (per my measurements and there is ZERO Combiner Loss). Note that I added a comment that Gain for DB-8e would be LOWER by about 0.5 to 1.5+ dB, not KNOWING the Insertion Loss for A-D's 2-Way Combiner...with lower loss on the lower Freqs. So to the first order approximation they are the SAME [w/o my HHH mod], with the CM4228HD usually being much less cost, uncertainty in Loss for A-D's 2-Way Combiner...and BTW: I have a mod to improve CM4228HD UHF Gain and also a mod to improve Hi-VHF SWR:
https://imageevent.com/holl_ands/multibay/8bayrefl/newcm4228hdwithhollandshorizharness
https://imageevent.com/holl_ands/multibay/8bayrefl/cm4228hdhhhtsrsyrod

However, Comparison Chart shows that W-G HD7698 and Monster All-Band HD8200 specs show the highest Gain over most of the UHF Band below 608 MHz (NEW UHF Band Highest Freq).

FYI: 2-Way Combiner Loss is the same as the Internal Loss when used as a Splitter....which is anything in excess of 3.0 dB in the fol. specs for hollands RF Splitters...who actually publishes both Typical and QC MAX Specs....unlike most other mfrs who are likely exceeding these "good" specs:
https://www.3starinc.com/manuals/GHS_CATV_Digital_Splitters.pdf [0.8 to 0.9 dB Internal Loss]
http://www.hollandelectronics.com/catalog/upload_file/Passives-GHS-HSU-Splitters.pdf [0.9 to 1.0 dB Internal Loss]

ACTUAL MEASUREMENTS show Max Loss CAN be a bit HIGHER:
I made on various 2-Port & 3-Port RF Splitter/Combiners in Jan2005:
https://photos.imageevent.com/holl_ands/files/ota/RF_Splitter_Loss RevB.xls.pdf
Tripelo made on W-G SD-3700 Splitter/Combiner in Nov2011:
https://photos.imageevent.com/holl_...Combiner Loss vs Freq - Tripelo 26Nov2011.gif
ADTech made on various 2-Port RF Splitter/Combiners in Jul2014:
https://photos.imageevent.com/holl_ands/files/ota/ADTech - Splitter_Comparison_Retail_2014.pdf
 
#7 ·
I believe forum member Zank_Frappa has built it.
Yes I built it but couldn't use it due to my balcony railing height. It didn't work work as well when I changed the reflector height to allow me to point it east and west as my FF4 can.

I am presently using the FF4 as seen here:

UHF Free-Form 4-Bay + DblAnglRefl

My version is the one with the 48"tall x 36"w (unfolded) reflector. It's a superb antenna and my hat goes off to holl_ands for all his fantastic work helping all of us OTA'ers maximize reception.
 
#8 · (Edited)
https://ypylypenko.livejournal.com/67090.html

retail price here is $8 USD
weight is ~700 g
zero wind resistance, prone to ice, wind, rain, dust & corrosion

https://ypylypenko.livejournal.com/33045.html
FF6 VDAR has outstanding perfomance (16+ dBi > 490 MHz, 15+ dBi > 470 MHz) but very big, heavy and complicated

We use 2xYagi when extra gain needed (distributed cabling or fringe areas), very cheap, very easy, 10+ years with no service, low wind resistance (no problem to use high mast)
 
#9 ·
Many antennas have a peak towards the top of the UHF spectrum, but low UHF is normally much weaker, and that is where the new UHF spectrum is, the general exception to this rule are a couple of the FAT DIPOLE antennas Hollands has modelled.
The $8 USD antenna Yuri mentions above, shows this too.
The FAT Dipole Antennas and some of Hollands simple and sweet loop antennas, like the Quad Trapezoid types with reflectors, have a much flatter gain across the spectrum, and less directional.

But if remodelled, I think all the antennas, being able to focus on a smaller spectrum, would preform better, yes?
Schoolbus
 
#13 ·
OldSparks. Thanks for pointing them out, very interesting. But Yagis are directional to an extreme, yes?

Regarding post #10, Majortom, that the whole idea- if the sidelobes could be merged into a stronger and broader main lobe, that would give better channel options (at least more useful for me, for me, the channels I am gunning for are 30-40 degrees apart from me).
 
#15 ·
Yes, when you squeeze a balloon, it tends to get elongated..
typically broader or wider beam = lower forward gain but easier to aim.

narrow beam = higher gain, more difficult to aim.
Again, every person's situation is different.
what is good for you, may not be good for someone else.
 
#16 ·
I tried modeling a NU-GH with full screen reflector for the new 470-608MHz band. Using trial and error, I just moved the y-coordinate for two points on each quadrant to make the elements longer, but hopefully nikiml's optimization scripts could find the best zig-zag formation for the new band. The following graphs compare the NU-GH with full screen reflector to nikiml's optimized GH10 and holl_ands' GH with split screen reflector.




NU-GH nec file: https://pastebin.com/VzrT3cGj
 
#17 ·
Started using nikiml's optimization scripts nikiml's Antenna pages - Nec optimization scripts to try to make a 470-608MHz Extended Hoverman similar to j3d's design that uses more zig-zags Extended Hoverman HDTV UHF antenna. I only added one extra zig-zag per quadrant than a normal GH and let the optimizer run without a reflector. Running the optimizer with a reflector grid took a long time and my computer sounded like it was going to explode (just kidding). Once the optimizer was done, I added a reflector grid and changed the size and reflector-to-GH spacing as needed.



X1-NU-GH with 1x1" reflector grid: Raw Gain 15.5 to 17.5 to 15.1 dBi, SWR max 1.74, F/R ratio min 20
nec file: https://pastebin.com/UcpGjD2M

X1-NU-GH with 2x2" reflector grid: Raw Gain 15.3 to 17.2 to 14.6 dBi, SWR max 1.75, F/B ratio min 12
nec file: https://pastebin.com/0swdYYyP

Measurements can be found here (important - separation between GH elements and reflector: 4.25" if using 1x1" grid, 3.75" if using 2x2" grid): nikiml's Antenna pages - Geometry viewer
 
#18 ·
Wanted to model a flat NU-FF6, so I took the holl_ands NU-FF6 with no reflector NEW UHF FF6 No Refl - OPT and added a flat 1x1" reflector grid (36x68" total size) with 6" reflector-to-bowtie spacing, and the antenna had over 16 dBi raw gain for the entire band. Below is a graph comparing the raw gain and swr of the NU-FF6, flat NU-FF6, and X1-GH. They're not that different in raw gain until the higher channels where the NU-FF6 has a whopping 3dB lead on the X1-GH at 608MHz. The NU-FF6 also looks like it has the best swr. I'm assuming a bit more gain could be added to the NU-FF6 with a 1x1" grid, but the angled reflector grids are trickier to make in a nec file (it takes less than 5 minutes to make a flat reflector grid in Excel).

 
#19 ·
YAGI_UHF_470-608MHz
Publishing in post #15, an antenna bowtie 4 and 8 bay for the new UHF band here:
Parts for antenna
Ask me like serious a yagi for such band and realised the analyze in mmanagal and 4nec2 go well, create that you can realise some adjustment but left it such as this.


Only is an analyze if you realised have care in the point of feeding of the dipole, in this web a similar example with the antenna.

Script the calculated using nickm's.
UHF Gain = 14.71 to 18.16 dBi, Min F/R=26.5 dB, SWR(300-ohms) Max=1.5
EVAL RESULTS:
Code:
Input file : /home/user/NIC/Yagi_XL_4nec2.NEC
Freq sweeps: [(470, 6, 24)]
Autosegmentation: NO

         --- Gain ---              -- Ratios -- -- Impedance --           
   Freq    Raw    Net   SWR BeamW    F/R    F/B    Real    Imag  AGT  corr
==========================================================================
  470.0  14.71  14.59  1.39  32.9  27.84  28.08  376.60  -80.63 1.00 -0.01
  476.0  14.91  14.82  1.34  32.3  26.76  26.76  352.16  -80.01 1.00 -0.01
  482.0  15.12  15.05  1.28  31.7  26.60  26.60  328.85  -73.06 1.00 -0.01
  488.0  15.31  15.27  1.22  31.2  27.40  27.63  317.25  -57.96 1.00 -0.01
  494.0  15.51  15.49  1.16  30.6  27.54  30.10  315.40  -42.27 1.00 -0.01
  500.0  15.72  15.70  1.13  30.0  28.11  34.57  318.45  -33.62 1.00 -0.01
  506.0  15.93  15.91  1.14  29.5  29.07  38.64  323.20  -32.49 1.00 -0.01
  512.0  16.15  16.13  1.15  28.9  30.13  34.73  321.24  -37.91 1.00 -0.01
  518.0  16.36  16.34  1.16  28.3  31.43  31.79  311.70  -43.16 1.00 -0.01
  524.0  16.55  16.53  1.14  27.8  31.13  31.13  303.48  -40.48 1.00 -0.01
  530.0  16.74  16.73  1.12  27.3  32.62  32.62  299.70  -33.88 1.00 -0.01
  536.0  16.93  16.92  1.11  26.8  34.61  36.87  298.97  -30.77 1.00 -0.01
  542.0  17.09  17.07  1.12  26.3  36.10  38.78  296.25  -34.25 1.00  0.01
  548.0  17.27  17.25  1.15  25.8  32.66  32.66  287.10  -38.63 1.00  0.01
  554.0  17.42  17.40  1.15  25.3  29.09  29.09  275.80  -32.85 1.00  0.01
  560.0  17.58  17.55  1.17  24.8  27.72  27.72  261.92  -23.16 1.00  0.01
  566.0  17.72  17.69  1.16  24.3  28.23  28.23  259.94   -6.76 1.00  0.01
  572.0  17.85  17.83  1.14  23.8  30.97  30.97  263.67    3.85 1.00  0.01
  578.0  17.96  17.94  1.14  23.4  33.29  36.19  263.80    7.82 1.00  0.01
  584.0  18.05  18.02  1.18  22.9  32.60  33.29  258.40   18.82 1.00  0.01
  590.0  18.12  18.07  1.24  22.5  28.46  28.46  259.28   45.19 1.00  0.01
  596.0  18.16  18.09  1.29  22.0  26.49  26.49  283.16   73.36 1.00  0.01
  602.0  18.15  18.07  1.30  21.6  26.69  26.69  340.18   73.76 1.00  0.01
  608.0  18.11  18.06  1.22  21.2  27.97  27.97  366.19   11.24 1.00  0.01
Auto segmentation=off
4NEC2 FILE:
Yagi_XL_4nec2.NEC
Yagi_XL_stub-down_4nec2.NEC
MMANA-GAL FILE:
Yagi_XL_mmanagal.maa
+ 4 images
here have the files:
YAGI_XL_UHF_470-608MHz
 
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