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Hello out there in ota land. This the first time I have tried to ask a question in the forum so please be gentle. My current setup is a cm- 4228 old style antenna with a cm 7777 amp. The antenna is 35 ft. from the ground. My local channels are 30mileish+ and I get channels in the 80s. Occasionally I can get Tulsa channels which are in the 110+ mile range but very weak signals. There is one channel (45) that I would really like to get. Is it unrealistic to try to build a single channel antenna that work at this range? If so would it be a yagi, Gray- Hoverman, or what?
 

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It's possible but you may be better off just getting a deep fringe UHF antenna. The Antennas direct 91XG should do the job. See chart here. There are some hacks that will improve gain here.
 

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Hello out there in ota land. This the first time I have tried to ask a question in the forum so please be gentle. My current setup is a cm- 4228 old style antenna with a cm 7777 amp. The antenna is 35 ft. from the ground. My local channels are 30mileish+ and I get channels in the 80s. Occasionally I can get Tulsa channels which are in the 110+ mile range but very weak signals. There is one channel (45) that I would really like to get. Is it unrealistic to try to build a single channel antenna that work at this range? If so would it be a yagi, Gray- Hoverman, or what?
Eldgreen, ScaryBob's suggestion is a good one, but to answer your question directly, when it comes to a single channel you really want, especially from such a range, a yagi is what you are looking for. Adding a corner reflector to it will help. I mention this, as the 91XG is rated by the manufacturer at 50-70 miles, falling short of what you may need at 110 miles, for reliability and consistency of signal.
 

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I would second the 91XG or M8 optimized for higher UHF channels. My 91XG with 4th boom extension pulls in RF48 from 114 miles no problem (85-90% signal strength 9/10 days). I also have an M4 antenna that slightly outperforms the 91XG on these 114 mile channels, upgrading to an M8 (vertically stacked with co-phase line M4 antennas) optomized for your deepest fringe RF45 could be hard to beat.
 

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My local channels are 30mileish+ and I get channels in the 80s. Occasionally I can get Tulsa channels which are in the 110+ mile range but very weak signals. There is one channel (45) that I would really like to get.
Post your TVFool image. Is channel 45 110+ miles away ? Chances are, since youre in the south, youre picking up those channels on tropo days, which are more common there. But tropo stations arent reliable reception. You can get a tropo forecast here : http://www.dxinfocentre.com/tropo.html
 

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Discussion Starter #6
arkansas deepest fringe antenna

Thank all of you for your response. I was not sure if I had done it right. My location per tvfool is Lat:35.36 ,Lon:-93.87. I'm disabled, so my budget is slim.I have 3 old vhf antennas that I was considering using for parts to make a long range single channel antenna but I wanted some knowledgable feed back. There is a web site called M7MEM that has a simple program for building a yagi antenna,but I didn't know how realistic the data is. I've also been wondering about the GH data. Dalek Prime ,you mentioned using a corner reflector to improve performance. What difference would it make.Is there a site showing how to make one? Again thank all of you for your response.
 

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Eldgreen, yagis are fairly easy to design and build, thankfully. The directors (more the better) are half wavelength of the channel you want. In general, the feed dipole is 5% longer than the directors, and the back element is 5% longer than the active element. A corner reflector is just an angled, larger helper to the usual reflector element, reflecting more of the wave back to be "recycled" towards the front, instead of just passing by, unused. Think of it akin to a helpful "catcher's mitt", or a shoreline breaker, folding the waves back.

Hope that helps. Feel free to ask more questions as needed. (And have a Merry Christmas, one and all!)

Btw, if the only material you can get is wire, considering your budget, the elements can be better made by using either folded dipoles, which mimic thicker elements, or bowties, which act similarly, mimicking conical elements. Again, these catch more of the wave. And remember, don't be afraid to experiment with the base design of any antenna. You won't know until you try it, and something may work better for a situation.

PS. Almost forgot. A corner reflector is fairly simple as well. It is, in essence, just two flat reflector grids, angled forward to reflect waves to be used, like so:

Yagi <---- (((((( RF waves

(As seen from side, left being the corner reflector, to the back. Think of those waves hitting the back, and being reflected forward again.)

Others here know more about the specifics of the GH than I.
 

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Discussion Starter #9
arkansas deepest fringe antenna

When you say regarding director elements "the more the better" where can I find out the spacings, lengths, etc. for an antenna tuned for 660 mgh frequency? Also is there any place where I could find out dimensions for a corner reflector tuned for the same frequency? I know I'm full of questions but here's another one. What is the best way to route the balun\coax on my old 4228? Thank you.
 

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What is the best way to route the balun\coax on my old 4228? Thank you.
If using a commercial balun, I would route the coax out the back of the antenna. You want to mount the balun so that water will drain out of it quickly. Also try reversing the balun leads to see if it gets a better signal. And different baluns can produce different results, even within the same model. You may even want to try your hand at building your own 4:1 balun from coax. For a narrow range of frequencies, theyre great. Search this forum for coax balun for directions.
 

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When you say regarding director elements "the more the better" where can I find out the spacings, lengths, etc. for an antenna tuned for 660 mgh frequency? Also is there any place where I could find out dimensions for a corner reflector tuned for the same frequency?....
The calculator you found at M7MEM looks quite sound, and will give you all the dimensions you need for your yagi, with the exception of an additional corner reflector, which can be any size, as long as it is usefully performing it's function of reflecting signals to the antenna. For quick estimations though, it's useful to refer to basic EM equations, the simplest being : frequency * wavelength = speed of light. Thus, at 660 MHz, the wavelength would be around 0.454 meters. That is your basic dimension.
 

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Although corner reflectors can be tuned for specific frequencies using rods, its much easier to use large mesh and overkill. IIRC, the basic effective minimum recommended size for a mesh corner reflector is 1.5 wavelengths wide by 2 wavelengths long for each corner reflector piece. Larger is better to the point of marginal utility. For channel 46, I would use 1" X 2" mesh.

As noted here http://www.hdtvprimer.com/ANTENNAS/types.html

"The point of this graph is that a Yagi/Corner-Reflector performs like a Yagi for the high numbered channels and a corner reflector for the low numbered channels. For the middle channels it outperforms the sum of the two types."
But it also increases the higher channel gain too.
 

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Might I add to the above information concerning corner reflectors, that it's fairly intuitive, angle of incidence being equal to angle of reflection, and a cursory sketch of rebound at various vertical points will give you the angle you want to set it at, given the height of each reflector, without overshooting your needs.
 

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Discussion Starter #14
arkansas deepest fringe antenna

I'm back. Before I do anything else as far as building another antenna, are there any tricks or tweaks that I can do with my cm-4228 to improve reception? Dalek Prime, I'm sorry but you lost me on your last post. Could you try to explain it again it again at my elementary level?
 

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Well, for channel 45, the old CM4228 is a pretty good antenna at about 15.5 dbi in gain. http://www.hdtvprimer.com/ANTENNAS/TemporaryPage.html
I would make sure you have a good balun and good connections on it.
Also, antenna placement could make a big difference. Moving the antenna a few feet in one direction or another, or up and down to locate a "hot spot".
 

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I'm sorry but you lost me on your last post. Could you try to explain it again it again at my elementary level?
Easier to show you.



Granted, this is specular reflection on a mirror perfect surface, but it illustrates my point that you can roughly predict where the wave reflection will strike the antenna if you know the angle it's coming in at.
 

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arkansas deepest fringe antenna

More questions. 1. What would be the best commercially made balun?2. I have noticed that some commercially made Yagi/corner reflectors have more than one driven element. Would this be to capture more of the deflected wave from the corner reflector? 3.Back to the subject of more director elements being better, is there a calculator to determine dimensions for adding more or should I stick with the specs. given on M7MEMs web site. I know I sound like a novice, but there's a reason for it...I am.
I hope yall have a very enjoyable weekend.
 

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1. What would be the best commercially made balun?
My preference is the made in Japan baluns, but they are hard to find even at flea markets.
The Channel Master and Philips ones are pretty good, but results can vary between units. The RS ones are the worst, especially in terms of $ per performance.
2. I have noticed that some commercially made Yagi/corner reflectors have more than one driven element. Would this be to capture more of the deflected wave from the corner reflector?
Well, maybe a little bit, but I think its done so they can get a bit more bandwidth.
3.Back to the subject of more director elements being better, is there a calculator to determine dimensions for adding more or should I stick with the specs. given on M7MEMs web site.
The calculator on that site allows you to input for more gain and elements, so use the calculated dimensions. You can also download the free program "Yagi Calculator", which is pretty good.
 

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Discussion Starter #19
arkansas deepest fringe antenna

Is it a no-no putting an inline amp. in an antenna coax that already has a preamp on it?
 
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