OTA reception 30+ miles NNE of Atlanta - AVS Forum
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post #1 of 11 Old 11-26-2012, 06:06 PM - Thread Starter
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Hello all,

I'm attempting to pull in as many stations as possible using an AntennaCraft HBU33 mounted in the attic.

EDIT: My original TV Fool report was at ground level. Updated TV Fool chart after adding 25ft to the AGL, which is more accurately representing where I've placed my antenna.


Here's what I'm working with in the attic: http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3dcc49122abaf724

Here's what I've done so far:

Mount the antenna in the attic of my 2 story home that sits near the high point of the neighborhood. Pointed it in a general SW direction, towards most of the towers that are around 200 degrees.
From the antenna, I have approx 75-100 ft of RG6 cable spliced together once, hitting a 4-way CommScope splitter w/ power amp (http://www.commscope.com/catalog/broadband/product_details.aspx?id=45402) that Comcast once installed to amp their signal to my TVs.
From the splitter, each run is prob 25-35ft of RG59 headed to the outlets.

The strongest signal I can receive is FOX 5.1 (WAGA) at around 70-75% strength, with 100% quality. NBC 11.1 (WXIA) comes in around 55-65%, but the sound cuts out for a split second every minute or so. ABC 2.1 (WSB) and CBS 46.1 comes in around 40-45%. Other channels such as PBS, ION, CW, and Peachtree TV come in as well around 50%. For the most part, except for NBC, the channels are fairly solid. ABC suffers from a constant audio drop or pixelation only after watching the channel for awhile (30+ min?); strangely, turning the TV off and on will cause this to cease for a good while.

I'm interested in what I can do to improve my signals. My first thought is that I should probably amp the signal closer to the antenna source, rather than 75-100ft away from it. This is easily possible since there is an A/C outlet in my attic near where I have the antenna. I've considered a CM-7777 for this purpose, but I've read a lot of bad reviews about the recent production line of them, so I'm not sure... I've also thought of possibly using separate antennas. Roof mounting is obviously preferable to attic mounting, but I'd like to avoid it if possible.

Any suggestions on a better antenna, multiple antenna setup, amp, etc. are appreciated.

BTW, for reference, the guy at the end of this post @ http://forum.tvfool.com/showthread.php?t=1321 seems to have had some luck with two antennas and two amps. I wasn't quite sure what to make of his post; I couldn't figure out which pieces of what he did actually helped him.

Thanks,
-T
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post #2 of 11 Old 11-26-2012, 08:05 PM
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You have severe terrain issues. The stations at about 200 degrees are very weak even though they're only 34 miles away. TVFool's "2Edge" notation indicates two sets of hills/ridges (or more) in your line of sight to the stations. You need to move your antenna outdoors to have any chance of getting them reliably. If the HBU33 doesn't do the job outdoors, move up to a combination of separate top-of-the-line UHF and VHF antennas: Antennas Direct 91XG for UHF and something like the Winegard YA-1713 for VHF (Antennacraft has a similar model but I don't remember the model number).

I have a 91XG / YA-1713 combination myself, with a Channel Master 7777 pre-amp (the old model). NM levels of about 0 to 5 dB represent the limits of somewhat reliable reception for me. This is in a suburban-type landscape with the horizon obscured by trees and houses across the street, etc.
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post #3 of 11 Old 11-27-2012, 08:41 AM
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Jtbell is on the right track. You really don't have enough antenna (at least in the attic) for what you're trying to receive. The HBU33 is a medium-gain antenna that wouldn't provide enough gain to reliably receive stations in the -2.5 db NM to +7.5 db NM range at the 201-204 degree heading on your TVFool report. The RG-59 coax plus a splice is also giving up some precious signal strength that would be preserved a bit more with a straight (and as short as possible) run of new RG-6. Is roof or chimney outside mounting an option? If so, you could perhaps do a quick test of your HBU33 outside at roof/chimney height using a temporary run of RG-6 coax through a window to your tv and see how it performs. If roof/chimney mounting is not an option, then a 91XG or DB8 for UHF plus an Antennacraft Y10-7-13 for VHF-high in the attic, connected together by a UVSJ and two short RG-6 coax pieces to a single downlead would be the next best option. You could amplify at the antenna if necessary instead of using an amplified splitter down the line.

http://www.solidsignal.com/pview.asp?p=db8
http://www.solidsignal.com/pview.asp?p=91xg
http://www.solidsignal.com/pview.asp?p=y10-7-13
http://www.solidsignal.com/pview.asp?p=uvsj
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post #4 of 11 Old 11-27-2012, 12:15 PM - Thread Starter
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Thanks for the suggestions! So, at the very least, I think I should get an amp closer to the antenna. My house wiring all terminates at a box on the outside of the house near the ground, so in order to split to multiple TVs, I have to first run a wire from the antenna to that box, then split it in that box out to the other TVs. I'm currently splicing a run from an unused bedroom to avoid running a wire from the attic outside of the house. That splice loses some signal quality - it's a barrel connector, but as I understand it, it's a very insignificant loss. Unless I run new wiring throughout (which is beyond what I'm looking to do right now), I'm going to have to amp whatever signal I do receive. As a test, I drug a 32" Visio TV up into the attic and hooked it directly to the antenna via a 25' cable (no amp). I was able to pull in the stations at 201-204 degrees, but the signal level was only about 20-40, depending on station.

It sounds like the focus needs to be on improving the signal strength somehow, either by relocating the HBU33 to the roof, or through the use of separate UHF and VHF antennas. To that point, two different styles of UHF antennas were recommended: The 91xg and the db8. Can you help me understand what the difference is between the two? My assumption is the 91xg is more directionally sensitive than the db8, but in return could possibly provide a stronger signal.

I'm hesitant to install this stuff on the roof for a number of reasons, but chiefly because I'm afraid of heights biggrin.gif Also, I'd think having the equipment in the attic would prevent headaches associated with inclement weather, which we often get here during the Spring thru Fall. So, ideally, I'd like to pull in these stations from the attic with the best possible signal, but I realize that the BEST signal will likely be had outside. The attic rafters are not insulated, and the antenna signal pretty much just needs to travel through some plywood and asphalt shingles. I'm also hesitant to take down the existing antenna and move it around, because it seems to be very sensitive to not only how it is placed, but where the coax wire falls from it. The last time I got up there and moved it around, it took me quite some time just to get my signals back to where they were before I began!

The wife is considering this a hobby of mine, but she also doesn't think that I need to mess with the reception we currently get because it's "good enough". Well, it's not good enough for me until it's as good as it can get, but I don't want to make the current situation any worse, so I think I may end up purchasing another antenna to move around with for testing reception in various areas, including the roof. To avoid dropping too much money on this hobby, I should probably purchase what could potentially be a better antenna than the one I have, in case I decide to swap it w/ the existing one. Would you still suggest avoiding a combo VHF/UHF antenna and just go with a UHF only antenna supplemented w/ VHF?
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post #5 of 11 Old 11-27-2012, 03:13 PM
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The techs at Dow Electronics on Boggs Rd .told me that the Channel Master 4228HD antenna works very well in the Atlanta market, and receives all major channels. It is an 8-bay antenna optimized for UHF, but can also receive HiVHF which is NBC 11.1 and PBS 8.1. And your preamp needs to be placed near the antenna with a one to three foot coax able from antenna to preamp. The power supply goes near the TV. You need a 2 way or 3 way splitter that indicates one port power pass depending upon how many TVs are connected. The cable from the power supply goes into the power port on the splitter indicated by the red line. But if your house is prewired with a cable panel in a closet that splits the coax to several different rooms, then you probably need a distribution amp in that control panel. Or the preamp would go at the antenna, and the power supply at the control panel. Because you definitely need to boost the signal close to the antenna. I would stop by Dow Electronics and ask their advice. They sell Channel Master and Winegard antennas and preamps. Open a wholesale account for the best price. And if you consider a UHF/HiVHF combo antenna, then I believe they sell the Winegard 7696 or 7698 antennas. And Fry's does also.
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post #6 of 11 Old 11-27-2012, 06:03 PM - Thread Starter
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Do you mean the Channel Master 4228 or the Channel Master 4228HD? After reading some of the reviews and comments on Amazon, I'm led to believe the manufacture of the 4228 is now being contracted to China, and the result is a steaming pile of crap with major quality control issues. Just like the CM-7777.

On the bright side, the 4228HD picks up "HD" lol:

* Picks up UHF, VHF, FM and HD

FYI - I just realized that my original TV Fool report was at ground level. Here's what I'm working with 25ft up in the attic: http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3dcc49d46eb9eb9e Again, I'm only interested in the channels at 201 to 204 degrees.

Also, I realized I was incorrect in the assumption I had RG59 cabling in the house. It's RG6 throughout.

I think I'm first going to try putting an AP8275 or 10G202 amp near the antenna and see if that clears things up. Pretty cheap first step, plus I'll probably need it anyway with the lengths of coax I'm going through. Next will be to try a higher gain, narrower beam antenna such as the 91xg to see if it can get a stronger signal, especially since I'm only interested in channels within a 4 degree separation. I'll have to do something about channels 8.1 and 11.1 with that solution though...
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post #7 of 11 Old 11-27-2012, 10:07 PM
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I was refering to the new version, the CM4228HD. It is actually a decent UHF antenna that also receives HiVHF. Works good in Atlanta area. But for the most part, the original Channel Master antennas and amps were superior products and were made in the USA rather than China. Most of the newer versions are not as good, but the 4228HD and 4221HD nevertheless can be good performers.The new 7777 preamp is not as good as the original version, and the original 4228 and 4248 were excellent antennas that sadly are no longer made.
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post #8 of 11 Old 11-28-2012, 09:30 AM
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The 91XG and DB8 are both excellent UHF antennas, and very close to each other in their respective gains. Either antenna will be very directional because they are both high-gain designs. In an attic, a DB8 might be preferred because it is a flat-panel design that can be placed closer to the very highest (central) point of your attic than can the 91XG with its long-boom horizontal construction. I had a CM4228 (the old kind, comparable to today's DB8) in my attic before moving it outside to the chimney a while back, and in the attic it would receive reliably down to around +6.0 or +10.0 db NM, unamplified. Outside, it's reliable down to about maybe 0.0 db to +5.0 db NM. I found that every bit of height was very important in my attic, so I hung my antennas using 1" PVC pipe from the rafters about an inch from touching the plywood roofboards.

For VHF-high, I can advise that my Winegard YA-1713 (which will have considerably more gain on VHF-high than either my 4228 or the new version 4228HD) will not receive VHF-high channels 11 and 13 (each at around +5.0 db NM) from my attic, but it will receive them just fine outside on the chimney. Apparently, the VHF signals are reduced more by the attic materials (maybe by 1/3) than the UHF signals (maybe by 1/4). Based on that, your WXIA-10 at +8.1 db NM will be tough to receive from your attic. If anything would get it, maybe the Y10-7-13 would. Also, using separate UHF and VHF antennas in the attic allows each antenna to be placed a bit higher than a single very long combination antenna.

It's probably best to get the best reception you can without amplifying, and then amplify only as necessary.
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post #9 of 11 Old 11-28-2012, 01:09 PM - Thread Starter
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Understood. Thank you for the informative responses.

I feel that I need to amplify since I'm running through almost 100' of RG6, which as I understand it, can cause around 5dB of loss. But I also understand the importance of amplifying a good signal vs just trying to make a bad one louder.

At this point I'm going to try the amp to see if it improves anything. I'd like to take that Comcast amp off the line because it's only giving a 15dB gain w/ around 4.5dB noise, plus it's a 4 way splitter, which is more than I need, so I'm suffering unneeded degradation from unused ports. Also, that amp is about 75' down the line from the antenna, so whatever signal it is amping is probably not the best by that point. I'm hoping that by putting a 10G202 on the line next to the antenna, I'll be able to boost a cleaner signal (3-5dB stronger due to it being next to the antenna as opposed to being 75' away) twice as strong (15dB gain on existing amp vs 29dB on the 10G202).

Either way, considering how weak my signals are going to be no matter what antenna I use, combined with my coax lengths, I feel I'm going to need a high gain amp. So if the amp doesn't get me to where I'd like to be, then the next step will be to try out different antennas in different spots.

BTW, I'm able to get all of the stations at 201-204 degrees. It's just they're not perfect all the time. The sound drops on WXIA about every 30 seconds, but otherwise there's no issue. Fox comes in perfectly. ABC usually comes in okay, and CBS seems fine. The other channels all seem alright, but i don't watch them that often. I just feel like the signal is on the low end of acceptable, and I'd like to get them as strong as possible without spending too much money or hanging antennas off of my chimney. I'll do the latter if there's no better way, but right now - especially with WXIA's sound cut out, I don't know if that's related to the signal or what. Because the TV tuner says I have 65% or so signal strength and 100% signal quality consistently, even when the sound cuts out for the half-second. Granted, I am amplifying a weak signal just to get the stations in where they are now, so that may be causing issues.
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post #10 of 11 Old 11-28-2012, 01:49 PM - Thread Starter
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Interesting. I just took off the 4-way CommScope splitter/amp and replaced it with a regular 2-way -3.5dB loss splitter. The CommScope has a loss of -7.5dB per port. So already by using it, that put me -4dB down, but it claims to amp +15dB forward, so shouldn't that be a +11dB gain (plus 4.5dB noise) in signal? I'm not sure how the noise factors into gain, but the results were not what I expected. Without the 4-way amp splitter, I'm seeing exact same performance and signal levels with a 2-way passive splitter. I expected slightly less signal with the 2-way, due to its lack of amplification. So now I'm confused.

My original plan was to take the CommScope splitter and put it up near the antenna to amp a stronger signal down the wire. But now I wonder if it's even able to overcome itself as a splitter. It seems not. When it's connected and the power source isn't plugged in, I can't receive signal on ANY channel - even the stronger ones such as FOX. I probably shouldn't expect so much from free Comcast installed equipment.

So, if the 4-way actually only has a -7.5dB loss on the port, and the 2-way has a -3.5dB loss, is this really telling me that I have a +4dB gain differential that's making all of my channels come in or not? And if the discrepancy is that little, then how much power/gain is actually needed to convince my LG TV's tuner that the signal is 70%? Because that's what it thinks Fox and NBC are coming in at right now. Subtract -4.5 dB of gain and it won't tune at all. Seems like tiny margins to me. Unless that -7.5dB loss per port on the 4-way is AFTER amplification.

Is there any easy way to see how much power is actually coming in? I'm guessing I'd need to purchase a meter. Unless someone has documented a way to correlate LG's signal strength indicator to actual power.
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post #11 of 11 Old 11-28-2012, 04:18 PM
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You need to keep splitters (passive) and distribution amps separated in your thought process.

A distribution amp is usually just a 15 dB amp in the same physical package with a splitter. A typical 2 output DA will have around +11.5 (15-3.5) dB boost per port, a 4 output DA will be around +7.5 (15-7.5 dB) boost per port, an 8-way will be around +4.5 dB per port. A "typical" noise figure for a quality DA is around 3-4 dB. Splitters are passive and don't require power.

An un-powered amplifier usually turns into a 30 dB attenuator, plus the insertion loss of the splitter.

The percentages display by internal signal meters are relatively meaningless and really don't correlate to the absolute power of the input signal. The actual "magic number" needed for reliable reception varies from one set to the next and you'll have to discover what your set needs. Perhaps it might need a "65" while some other set only needs a "40". The bottom line is that, if you are getting reliable reception, the absolute number is irrelevant and there's no point in just chasing an higher number for braggin' rights.
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