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Discussion Starter · #1 ·
If so I am very interested in your results. I have searched to see more info on the DAT45 and price. Does it have a built in amp?? My objective is to get digital channel 44 at 96kW ERP at 32 miles. Currently I do not get even a blip with my MyHD card. On the analog channel, I get some major ghosting and assume multipath is the culprit on the digital side. Here is the analog channel image:
http://members.cox.net/timcarson/Image1.jpg


Here is my situation:


Manhattan, KS - We are in a "bowl" with the flint hills all around us. I live very near, like 1/2 mile from some large hills that are between us and the majority of the local analog stations. I have analogs 11(PBS) 13(CBS), 15(Fox), 18(FOX), 27(NBC), and 49(ABC) (locally) that I would like to pick up so I can drop the cable company. I currently have a very cheap radio shack VHF-UHF antenna, VU-90 about 25 feet up(cannot go higher). No preamp. I get 11 very snowy, 13 ghosty but good signal, 27 awful snowy mostly not watchable, 15 great, 18 pretty snowy, 49 pretty snowy and ghosty.


Now, when there is just a hint to tropo, I get some Wichita and Hutchinson stations. I on occasion (3 of last 4 nights) get 8 snowy, 10 a bit snowy, 12 decent with snow, 24 not great and 33 watchable with snow. I should note that all the Hutch and Wichita stations are a little over 100 miles.


On to the important part, the digitals. I have digital locally that are channels 28 at 1kW ERP and channel 44 at 96kW ERP. Channel 28 is analog 27, so I am SOL with it. There are also channels 19(119kW STA), 17(65kW), 21(87kW STA), 26(350kW DA), and 31(unsure kW) coming from Wichita at varying powers.

You can see in the picture where they are in relationship to me, and their analog and digital channels with distance. If someone can take a look at my map, and give some suggestions, I would greatly appreciate it. I know the DAT45 is UHF only, but I am mostly interested in digitals, but would like analogs too since locally(Topeka) there is no WB or UPN, so I would have to come from Wichita.


Here is what I am looking at:

Analogs: 8 - 10 – 11 – 12 – 13 – 15 – 18 – 24 – 27 – 33 – 49

Digitals: 17 - 19 - 21 - 23 - 26 - 28 - 31 - 36 - 44 - 45 - 48


Here is a map I made to give an idea(visually) of my situation.

http://members.cox.net/timcarson/TVMAP.jpg

I know gif would be better, but jpg for file size


Thanks!!!
 

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O.K. you have some hills to climb (no pun intended) if you are willing to spend some money you may get ota digital. I would get the dat 75 and amp it with the 7777 channelmaster, you will also need a rotor and a tilter to aim up at the peak of those hills, maybe even a horizontal stack with al of the other stuff. Look at this page for a bunch of tests with hills in the way http://www.atechfabrication.com/ be sure to follow the link to the thread back here. The tilter may be key in your location.
 

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I agree pretty much with dynamo.


Every situation in reception of digital is different. The only way you will ever know is to try. You will need the equipment listed in above message. Height is the most important consideration in your case. Picture the transmitters towers out there and your antenna head must 'see' those transmitters..or, a least, come very close to seeing them. Actually there is a tilting bracket (s) on the DAT75. I would aim the antenna 'up' some 15 degrees to begin. You will have to 'zero' in on the transmitters as a few degrees..(talking left and right now) can make a difference I have found. Remember, get all the height you can. Let us know how you come out. Read all the helpful links here and Happy Viewing. It will be well worth the effort..and money.
 

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Discussion Starter · #4 ·
Well, I know about the DAT75, but was curious about the DAT45 because of the smaller size and I believe there is a built in Amp right?? My wife has pretty much said nothing more untill the holidays are over. I don't have alot of room to move the antenna around and cannot go higher. I do have a rotator, but the tilter I could try. If I can tilt the DAT75 without buying something else, I might give that a try. I had planned on getting the 7777 but thought if the DAT45 had one built in, I might try that first.


thanks guys!
 

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timmy..


The DAT45 is slightly cheaper in cost but if you buy the 'pre-amp' it will bring the cost up to cost of DAT75. Then, can you just plug the 'pre-amp' into a wall outlet in USA? Probably not. My opinion..better to buy the DAT75..see if it works without a pre-amp; if you need a pre-amp, buy a Winegard or CM (such as 7777) that supports UHF and VHF with 2 inputs..one output. The 2 main considerations is distance and line of sight. You must have reasonable line of sight from antenna head to transmitters and a distance not over..let us say 60 miles..and that would be pushing it. Under 40 miles becomes more ideal, in my opinion, if you want near perfect reception. Between 40 and 60 miles is where you really have to work at it to get all the signal you are able. Of course, the higher you can get that antenna, the better. I have mine at 30 feet for 55 miles.
 

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By the way, if you want both UHF and VHF, you will need a separate VHF antenna or, in the beginning, buy a large combo from CM or Winegard. Generally speaking, separate antennas will give you more gain overall than a large combo. Of course, the cost also is higher.
 

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My analog UHF picture was very similar to yours using a single Blake JBX21WB or a Televes 75. (I have no line of sight to xmitters 33 miles away). The digital channels were not reliable with the single antenna.


The magic bullet for me was a horizontally stacked pair of JBX21WB's. I suspect that stacked Televes 75's would have been almost as good. Rather than experiment endlessly, I ended up going for the best possible arrangement: Blake JBX21WB's, even though they cost more.


Summary: With your ghosting multipath problem, whatever antenna you choose, stack two of them horizontally on a rotor. I suspect you might need a preamp and the bigger antenna since you have snow on some channels.
 

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I thought the whole reason behind the three separate director arrays on the DAT75 was to elimimate the need for a tilter, since it can pick up from 3 separate elevations, or does it act more to trap the signal between the top and bottom directors and feed it to the middle directors?
 

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Dave..............On the DAT75..of the 2 options you gave in your message for the 3 director displays, I had thought the former was true but was told, one day, on here by someone (who seemed to know) the latter of the 2 options was a fact. As I said, there are 2 brackets on the antenna and they both can be adjusted as to elevation. I have mine so that the lowest reflector is level with ground but was told it is better with the bottom brace was to be level with ground. I am getting everything I need very good as of now so will wait til warmer weather to experiment more with different elevations. I know the elevation can make a difference and. probably, every reception situation is somewhat different. Bottom line, I do not think a person would need a separate elevation bracket with antenna unless you wanted to control same from ground level. As stated above, my antenna is adjusted so that lowest of the 'probes' is level with the ground. That actually makes the uppermost of the 3 'probes' looking at maybe a 25-30 degree angle from the level ground.
 

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Quote:
Originally posted by Davenlr
I thought the whole reason behind the three separate director arrays on the DAT75 was to elimimate the need for a tilter, since it can pick up from 3 separate elevations, or does it act more to trap the signal between the top and bottom directors and feed it to the middle directors?
Dave, it depends on what makes tilters work in the first place that would answer your question.


The general theory by those selling/advocating tilters is that signals do not always travel parallel to the ground and they may be reaching a particular location slightly above/below the virtual horizon. Thus, tilting the antenna to "catch" this wave makes reception improve.


It is also well known that each station seems to have a "sweet spot" in its wave once you're dealing with distant reception, where the signal is strongest in the wavelength. Thus, moving an antenna up or down can boost signal for a single channel. (The problem being that each signal has a different sweet spot and you would need to move the antenna up or down for each and every station.) It is my theory that the tilters actually adjust the height of the antenna and thereby improve reception.


The DAT45/75 design is best viewed from above. It becomes clear that at each dipole location, there are 3 diploes aligned vertically. These dipoles act as directors, concentrating the signal finally on the active elements (thus, the dipoles above and below the "main" boom gradually draw closer to the center boom to direct the signal that way.)


Ed in Wisconsin installed a pair of DAT75s horizontally and found the tilt adjustment still made a huge difference on some channels at distance.


Either way, it is clear that the aditional elements don't really serve to fix what the tilter is supposed to do.
 

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Televes can be ordered by emailin [email protected] it takes 3 days and costs around 136.00. I thought that the tilting might be the way to go with hills above and between the reciever and the transmitter, maybe someone more familiar with this type of signal propagation could better answer this, but I thought the signals come off the crest of the hill and come down at an angle... am I wrong?
 
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