Houston: How do you diagnose what you need? HDTV Antenna / Pre-amp / CM4228 vs. 91XG - AVS Forum
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post #1 of 12 Old 09-07-2014, 01:17 PM - Thread Starter
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The Woodlands, TX: How do you diagnose what you need? HDTV Antenna / CM4228 vs. 91XG

I'm a recent cable cutter, but I'm running in to issues. First, I live in The Woodlands (Houston), Texas (77381). This puts me about 45 miles directly North of all the towers in Missouri City. I live in a two-story house with an attic. Installing an antenna outside isn't an option so I'm left to install it in the attic.

Recently, I purchased a Channel Master 4228HD antenna (8-bay). I aimed it South and the channels I wanted came in (NBC, CBS, ABC, FOX, PBS). I felt pretty good about things until I started doing some daily viewing. Intermittently, CBS would get a bunch of artifacts on the screen. Later it would come back perfectly. Then PBS would get artifacts and later come back perfectly. NBC, ABC, and FOX are always solid. Yesterday I was excited to watch US Open Tennis on CBS, but when I turned it on there were a ton of artifacts. I reluctantly went up to the attic and moved the antenna only slightly. Voila, CBS comes in perfectly, but PBS dropped off completely.

So I'm left to continue tinkering until I find a solution, but how in the world can you know where you need to go? I've read up on pre-amps. Do I need one? The antenna is connected almost directly to the main splitter, which then goes to all the rooms in the house. This is not an active distribution amp, but the typical ones you would find in any cable installation. Do I possibly need an active distribution amp? I have no idea. Then I go back to the antenna. As I read more and more I find the CM4228HD is highly regarded, but the 91XG might provide an edge. Is the bottleneck the antenna itself? I don't know and I'm not sure how you diagnose where you should be concentrating your efforts?

I'm fairly close to just buying the 91XG and a Channel Master 7777 Pre-amp just to see if they provide any difference, but again, I've got to believe trial and error isn't the best way of approaching this. Any guidance is appreciated.

Below is a link to my TV Fool data:
http://www.tvfool.com/?option=com_wr...d243652533f7b3


Last edited by JP; 09-09-2014 at 06:28 AM.
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post #2 of 12 Old 09-07-2014, 01:37 PM
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post #3 of 12 Old 09-07-2014, 03:32 PM
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Quote:
Installing an antenna outside isn't an option so I'm left to install it in the attic.
Wanna bet? See http://www.fcc.gov/guides/over-air-r...n-devices-rule

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The antenna is connected almost directly to the main splitter,
What it is the make and part umber of the splitter?

You have a UHF-mostly antenna. Three of your Houston majors, ABC, CBS, and PBS are all VHF and the antenna you have (and the proposed 91XG) are specialized for UHF. All you need to do is recognize two things: You need an antenna for channels 7-13 and you *might* need to put it outside, up in the air, so that signals can actually get to it. Depending on your available space and construction materials, you might get away with adding a 7-13 antenna and keeping it in the attic. A premium and excellent choice would be the ultra-compact ClearStream 5. A cheap attic option would be the AntennaCraft Y5713, but you'll also have to buy a matching transformer and a UVSJ to combine the two antennas.

The CM7777 would be a compete waste of money. Your problem isn't signal power (really the only thing an amp can address), your problem is that you don't have an antenna that can efficiently pick up high VHF channels. The 4228, like most UHF 8-bay designs, tends to pick up VHF at odd angles compared to their UHF reception patterns.

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I've got to believe trial and error isn't the best way of approaching this.
You're right, it isn't.
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post #4 of 12 Old 09-09-2014, 06:47 AM - Thread Starter
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Done, and thanks.

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Originally Posted by ProjectSHO89 View Post
Sorry, I should have fully qualified things here. When I say it isn't an option, it has to do with me. I don't want to pay anyone to install an outside antenna, I sort of don't want it out there because I don't think my wife would appreciate how it looks, I don't want to get on top of a two-story house because I'm pretty certain I would fall and break my neck, etc.. I just like the thought of an attic installation much much more even though I know it comes with plenty of drawbacks.


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What it is the make and part umber of the splitter?
I haven't looked, but it is just your run of the mill passive splitter. It is 1in / 4out and I think I saw it loses 7db on each of the outputs. I know I could possibly improve on this, but I feel pretty confident you have it right later in your response. My issue is probably more with the antenna and less with the distribution from the antenna to the drops.

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Originally Posted by ProjectSHO89 View Post
You have a UHF-mostly antenna. Three of your Houston majors, ABC, CBS, and PBS are all VHF and the antenna you have (and the proposed 91XG) are specialized for UHF. All you need to do is recognize two things: You need an antenna for channels 7-13 and you *might* need to put it outside, up in the air, so that signals can actually get to it. Depending on your available space and construction materials, you might get away with adding a 7-13 antenna and keeping it in the attic. A premium and excellent choice would be the ultra-compact ClearStream 5. A cheap attic option would be the AntennaCraft Y5713, but you'll also have to buy a matching transformer and a UVSJ to combine the two antennas.
You have got to be kidding me (and thank you)!!? I've done all this research online to now find out I'm using the wrong antennas? I didn't even know there was a difference. A general rule of thumb seems to be "bigger is better," but I see now that isn't always the right answer.

So what should I do? I don't really need cheap because these antennas are already fairly inexpensive in my mind. I plan on purchasing the ClearStream 5 today and that will hopefully get in the VHF channels I want. I guess I should try that and see if it is enough to pull in the UHF channels I need as well? OR should I try for more of a sledgehammer approach and get a dedicated UHF antenna. Up until this point I didn't even realize two antennas might be an option, but I see the ClearStream 5 comes with some kind of connector to do this...right? I'm visioning that the UHF antenna connects to this coupler on the VHF antenna and then one coax cable is sent out...correct?

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Originally Posted by ProjectSHO89 View Post
The CM7777 would be a compete waste of money. Your problem isn't signal power (really the only thing an amp can address), your problem is that you don't have an antenna that can efficiently pick up high VHF channels. The 4228, like most UHF 8-bay designs, tends to pick up VHF at odd angles compared to their UHF reception patterns.
Well, this will be easy enough. I bought it, but I'll probably just return it as soon as it arrives. It would just a shot in the dark at a potential solution for what I was seeing.

Funny thing is the more I watch the different stations the more I notice the UHF channels and the VHF channels will occasionally produce artifacts. It is really weird because it can be a completely clear day and some channels will come in and one or two might have artifacts. Then it can be raining and the same might hold true or a different combination. There doesn't appear to be any real pattern so I still feel like I'm stuck in this "trial and error" cycle until I find something that works and holds the signal for all the major networks all the time.
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post #5 of 12 Old 09-09-2014, 06:58 AM - Thread Starter
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I just had a crazy thought. Would a "sledgehammer" approach be using both the 91XG and the ClearStream 5? Those two antennas seem to be the best in their respective class (UHF and VHF)...right? If I can't get a stable signal coupling both of those I've got to believe I'm out of luck (for an attic installation at least)...don't you think?
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post #6 of 12 Old 09-09-2014, 11:57 AM
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If you're already getting all the UHF channels (those except 8, 11, & 13), then you only need the high-VHF antenna recommended.

The ClearStream 5 comes with the combiner to add it to an existing UHF antenna. You'll need to provide two short coax cables to make the connection between each antenna and the combiner as they are not included.

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post #7 of 12 Old 09-09-2014, 12:03 PM
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The CM-4228 you already have should perform well for your UHF channels. Just add the Clearstream 5 VHF antenna with a UHF/VHF signal joiner, which can be purchased at RadioShack. A preamp may be helpful at 45 miles, since you have a 4-way splitter. But the CM-7778 with a moderate gain is what you may need, as the CM-7777 will overpower. Or you could try a CM-3414 distribution amp in place of the 4-way splitter.
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post #8 of 12 Old 09-09-2014, 12:36 PM
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Originally Posted by tylerSC View Post
The CM-4228 you already have should perform well for your UHF channels. Just add the Clearstream 5 VHF antenna with a UHF/VHF signal joiner, which can be purchased at RadioShack. A preamp may be helpful at 45 miles, since you have a 4-way splitter. But the CM-7778 with a moderate gain is what you may need, as the CM-7777 will overpower. Or you could try a CM-3414 distribution amp in place of the 4-way splitter.
Agreed.
Two antennas, one for UHF and one for High-band (7-13) VHF is a great solution.
While at it, you might want to add a small, omnidirectional FM antenna in the attic, and run it (on a separate cable, even) to your FM Radio tuner.

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post #9 of 12 Old 09-10-2014, 06:12 AM - Thread Starter
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Agreed.
Two antennas, one for UHF and one for High-band (7-13) VHF is a great solution.
While at it, you might want to add a small, omnidirectional FM antenna in the attic, and run it (on a separate cable, even) to your FM Radio tuner.
So how do these couplers work that attach the UHF and VHF antenna? Do they completely filter out UHF signals on one antenna and VHF for the other or do they work together in some way? Say for instance you have a primary VHF antenna and a primary UHF antenna and the primary UHF antenna happens to pick up a VHF signal pretty well whereas the primary VHF antenna has dropped it off. Is the VHF signal from the UHF antenna still carried through the coupler or is it filtered out?

The reason I ask is over the last couple days the 4228HD has been picking up everything pretty well without any artifacts on anything and I would hate to lose what it is providing on both the UHF and VHF frequencies. Of course I only experience significant artifacts the instant I want to watch some kind of specific programming (US Open Tennis). No idea why that is, but the information I'm gaining here is helping me near a solution.
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post #10 of 12 Old 09-10-2014, 09:44 AM
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The UVSJ filters and separates the UHF and VHF signals. The UHF port will only pass UHF, and VHF will be blocked. The VHF side only passes VHF, and blocks UHF, regardless of which type of antenna used.
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post #11 of 12 Old 09-15-2014, 02:46 PM - Thread Starter
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Just so I'm clear on something here, if my current setup provides picture perfect HD on the channels I want 99% of the time then it is extremely unlikely (closer to almost no possibility) that a Pre-Amp and/or Distribution Amp will provide any benefit...correct? The issue resides somewhere with the antenna(s) or the signal itself.
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post #12 of 12 Old 09-29-2014, 11:33 AM - Thread Starter
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I thought I might put a little closure to this post since others might benefit from The Woodlands, TX. Ultimately, I went back to the exact same infrastructure I started with. The CM4228HD has impressed me the most over the long-term. I never bought a VHF antenna and I never took the 91XG out of the box. I also never installed the CM7777 pre-amp. Basically, my setup is simply the CM4228HD installed in the attic and connected to all the runs in house by way of a regular passive splitter.

The UHF channels I want to get in (major networks) are pretty much rock solid. The VHF channels are almost always perfect except for PBS and CBS. What I've found is during the very hot days in the middle of the day either PBS or CBS will display artifacts. I slight adjustment (1/2" maybe) will allow for PBS to then come in clear, but CBS won't. A 1/2" nudge in the other direction will cause CBS to come in perfect, but PBS won't. What I've elected to do is simply leave it where CBS comes in clear almost all the time since I watch it more than PBS. It has worked out really well.

For the size and the ease of installation I've got to say the CM4228HD is pretty amazing. I'm really happy with it and hope it will continue to work well for years to come.
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