DTV antenna signal distribution


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Old 11-25-09, 10:24 AM
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DTV antenna signal distribution

We are looking into changing from our current satellite installation to just getting digital locals off the air. I will be mounting a DTV antenna on the old satellite post at the peak of our roof, so we will have an unobstructed 360 degree range of view. We are 16 miles from the transmitters. Our three TVs are all analog, so I know I will need DTV converters for each.

My question relates to getting the antenna connection to each of the three rooms. I have RG6 from the roof location to my distribution panel, and RG6 homeruns from each room to the distribution panel.

Can it be as simple as putting a splitter on the coax from the antenna, and attaching each of the room cables to the other side of the splitter? Would it be a special kind of splitter?

One of the TVs may be just outside the 75 foot range (as I have read online) and may require amplification. Can/should I put the amplifier before the splitter (if that is the solution from above), or just on the line to the TV in question?

I have a parts shop nearby with just about every imaginable thing I would probably need except clerks who know what they are selling (sigh). I am grateful for this forum for filling that gap.

-Jim-
 
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Old 11-25-09, 10:35 AM
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Several things...theres no such thing as a "DTV" antenna. A regular good quality antenna will work just fine. No Pro, but it seems like digital signals are UHF..if so..you won't need the VHF part of a regular antenna.

And why are you changing what you have now...you can probably just hook the RG6 on the roof to the antenna, then put the converters at each TV..it may work fine w/o any amplification...try it first.
 
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Old 11-25-09, 11:38 AM
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Keep in mind TV reception is determined by the size and type of antenna and the direction in which it is pointed. I believe digital tv signals are directional - meaning the antenna needs to point towards the source of the signal versus an omni directional attena.

Check out antennaweb.org, you can enter your address (just zip code) to determine the type of attena you need as well as the direction to point it for best reception.
 
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Old 11-25-09, 12:04 PM
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@Gunguy45 - We aren't really changing anything physically much, just getting rid of satellite service and picking up digital broadcasts instead. I realize the antenna nomenclature was sloppy on my part; our deed restrictions will not allow the typical antenna of days gone by, but the new style (Clearstream, for example) are acceptable when mounted in a similar fashion to a satellite dish.

Anyway, we'll still use the existing RG6. All we're doing is pulling off the dish and attaching something new to the post. I realize now the original post was not clear that we were dumping satellite entirely.

@njnorsky - Yes, understand the directional characteristics of the digital transmissions, thus we will be installing something like the Clearstream antenna and aiming it properly. I did already check out antennaweb.org which is how I determined our distance to the transmitters (16 miles) and their direction (107 degrees).

So, I'm still left with wondering if a basic splitter is all I need to take a single feed from the antenna and split to three TV locations. We've been on satellite for so long with all the fancy multiswitches and diplexers it just sounded too simple to me to slap a 1 to 3 splitter in there.

Also, IF I end up needing amplification on the farthest TV, do I amplify just that one cable or the entire incoming signal? Can you over-amplify?

Thanks for the feedback.
 
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Old 11-25-09, 06:16 PM
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The digital signals are no more directional than the analog signals but they are often of lower power and therefore have a lesser range. Both the UHF and the VHF frequency band are used for digital television signals so unless you know for a fact that none of the broadcasters in your area are using VHF you are best to get a combination VHF/UHF antenna.

Yes, it really is as simple as one coaxial cable from the antenna to the distribution point and then using a 3-way splitter. You may need an amplifier and you may need it either before the splitter or on the one longer cable. You will have to try it both ways to see which is better.

Be sure to get an amplifier (if you determine you need one) that is compatible with digital signals. You may be better off to get a combination amplifier/splitter, often called a distribution amplifier.

I'd try just a simple 3-way splitter first. I'm pretty sure you can get one for less than $10. at any big box megamart.
 
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Old 11-25-09, 06:53 PM
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I believe a mast mounted amplifier would be the best if you need it.

You can always mount a larger antenna in your attic if you have space. I had canceled my cable service for awhile and ran an antenna like that for DTV. Worked fairly well for being fixed in one direction.

I'm not too familiar with how deed restrictions work, but there is a federal law that doesn't allows restrictions on the installation of tv antennas.
 
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Old 11-25-09, 07:09 PM
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FCC Fact Sheet on Placement of Antennas

That's the FCC rule. Lots of info there regarding the rule. Basically, there can be restrictions as long as it doesn't impair your ability to get a usable signal.
 
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Old 11-25-09, 11:52 PM
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Use a barrel to connect the incoming antenna cable to the closest TV drop in the house. If the picture is clear and doesn't freeze, you have good incoming signal.

Make sure the splitter is capable of passing up to 900 MHz.

Insert the 3-way splitter and connect all the TVs. If you don't have good pictures on all of them, you'll need an amplifier. If the closest TVs get a good picture and the 75-footer is erratic, you'll still need an amplifier.
 
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Old 11-26-09, 07:53 AM
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Just a few tips,

If you need to cut the coax be sure to only use the correct tool, a coax cutter. It won't damage the cable as it cuts it. Regular cutters can crimp the cable and that will affect the impedance. Use the correct tool to strip the coax as well. You don't want to nick the insulation.

Use barrel connectors, not the screw-on or cheap crimp-on type. They might be called Thomas & Betts compression connectors or SealTite connectors. They use a special tool to install but will be of the same quality that your satellite (or cable) company uses. The big box stores carry kits.

On a 3 way splitter, they should mark the db loss per port (better ones will). Usually on a 3 way you'll have 2 ports with about a -3.5db loss and one with a 7db loss. You may be able to find one that is equal. These are called "balanced splitters" which lose about 5 or so db per port, but all ports lose the same.

You could also get a distribution amplifier. These will allow you to connect as many tv's as you want without loss. But as
drooplug says, it's better to put an amplifier on the mast, ahead of the splitter. They are remote powered over the coax, then use the 3 way splitter.

If you plan on using an amplifier make sure the splitter will pass power to it. It will say on it "power passing" or similar. They do cost a few $ more than the cheapies.

Terminate any unused port, don't leave it open.

Remember with DTV, it's an all or nothing proposition. Either it works and you have a clear picture or you have nothing. There is no in-between (unless you call breaking up or pixelation in-between).

You should do fairly well at 16 miles. I'm not to worried about the 75' either. I'm running close to 100' from my antenna to feed 2 tv's and am at almost 30 miles from the tower, no problem and signals in the 90's.

Try it and see what happens. Good luck and enjoy the picture.
 
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Old 11-26-09, 06:10 PM
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Thanks, furd! And appreciate the advice on the distribution amplifier. Very helpful.

Jim
 
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Old 11-26-09, 06:23 PM
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Thanks, drooplug. Yeah, the restrictions don't disallow them, but do have some requirements on placement, appearance, etc. And while they may be technically unenforceable, it does keep things looking somewhat "clean" around here and I'd like to be a good neighbor.
 
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Old 11-26-09, 06:36 PM
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Thanks, Rick and aandpdan! Very good information. I do have the "good" cable making tools (only get to use them infrequently, but do get to loan them out now and then for a nice glass of scotch and a good cigar, so worth the purchase!). I'm hoping, however, that I won't have to do any cutting and retermination as the current satellite feed already comes in to a multiswitch and then out to the target rooms.

I'm jazzed now to tackle this project this weekend. I really appreciate the help!

Jim
 
 

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