  frankpf3 verizon.net
join:2007-08-09 Huntington Station, NY
·Verizon FIOS
| Line Attenuators
I was having a problem with two HD channels not coming in. I removed some of the line attenuators that the original install tech put on the line and all is fine now.
Are the attenuators still really needed? Maybe Verizon has lowered the Db level from about 1 1/2 years ago? i now have only 1 attenuator left on the line coming out of the ONT to the splitter. |
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  danclan
join:2005-11-01 Midlothian, VA
·Verizon FIOS
| maybe your cable plant is the issue. Either connections or aging wire.
I know I had specific issue with 2 hd channels and merely refitting all the cables together resolved it.
I wouldn't remove the attenuators unless recommended by verizon as you could damage the stb's. |
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 pdressler
join:2001-03-04 Wyckoff, NJ
| reply to frankpf3 I was having some issues with the picture stuttering on HD channels during HD football games. Anyway the tech (who seemed knowledgeable) came to look and saw that my original installer used a few attenuators. He told me that they do cause some problems and that a proper install should not use them at all. The preferred method is to come out of the ONT and split as many ways as needed to have the correct DB level on each line. For me it was 8, so I have an 8 way splitter right after my ONT and no other splitters or attenuators in the system. Note you do not have to use all the lines just because you split it that many times for the correct levels. I have not had any problems since that.
I don't know if this is really legit or not but it seemed to work for me so take it for what it is worth. |
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  frankpf3 verizon.net
join:2007-08-09 Huntington Station, NY
·Verizon FIOS
| reply to frankpf3 I had a problem on my DVR which is farthest away from the ONT. Channel 803 and 804 was coming in as "channel unavailable". I removed the attenautor and all is fine. Now I just have one attenuator on the coax coming out of the ONT (the attenuator seems built into the connector, I can't remove it) and this goes into a 3 way splitter, with some in line extenders along the way.
Can the in line extenders reduce the signal also? And why would this be needed at intall alsomost 2 years ago, but now cause me problems? I bet the signal strength dropped for some reason? |
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  matcarl
join:2007-03-09 Franklin Square, NY | Line extenders do drop it down a little, but it is a mystery why it would change if nothing was touched. I have noticed slight variations on my lines too which haven't been touched. I wonder if my levels have dropped too. |
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  frankpf3 verizon.net
join:2007-08-09 Huntington Station, NY
·Verizon FIOS
| I was one of the first in my area to get Fios TV when it rolled out around November of 2006. I wonder if because most likely their is a larger user base, the Db level has dropped to each home, where 2 years ago, the signal was hotter with less users on board.
if this is true, Verizon is going to have problems with all those initial installs and all those attenuators sitting on everyone's lines. |
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 DMS1
join:2005-04-06 Carrollton, TX
| said by frankpf3 :I was one of the first in my area to get Fios TV when it rolled out around November of 2006. I wonder if because most likely their is a larger user base, the Db level has dropped to each home, where 2 years ago, the signal was hotter with less users on board. if this is true, Verizon is going to have problems with all those initial installs and all those attenuators sitting on everyone's lines. It doesn't work like that. The signal level on the coax is governed by the ONT. Although the optical power level of the video signal could change, the ONT has an automatic gain control to peg the output level at +18 dBmV. |
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  frankpf3 verizon.net
join:2007-08-09 Huntington Station, NY | Then why all the attenuators and why such a high gain? Shouldn't the tech then adjust the gain through the ONT? |
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 DMS1
join:2005-04-06 Carrollton, TX
| said by frankpf3 :Then why all the attenuators and why such a high gain? Shouldn't the tech then adjust the gain through the ONT? It's not adjustable. The purpose of the AGC is to maintain a constant output level regardless of the input level. I'm not sure why the ONT designers chose the level they did. It does correspond to the ideal level at the tap for cable TV, but then there is normally a lengthy cable run from the tap to the first splitter with cable. A level of +15 dBmV would have probably been more suitable for most cases. May be they went on the high side because attenuators are cheaper and easier to install than amplifiers. |
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  frankpf3 verizon.net
join:2007-08-09 Huntington Station, NY
·Verizon FIOS
| My first and only 3 way splitter is as soon as the coax comes out of the ONT. Then the cable run comes into the house with a few line extenders along the way. i did remove one attenuator they had directly behind the DVR box itself. It did correct my channel unavailable problem. Should I be concerned about frying the box? |
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 knarf829
join:2007-06-02
| said by frankpf3 :My first and only 3 way splitter is as soon as the coax comes out of the ONT. Then the cable run comes into the house with a few line extenders along the way. i did remove one attenuator they had directly behind the DVR box itself. It did correct my channel unavailable problem. Should I be concerned about frying the box? 1. If you weren't getting some channels, obviously the signal was too low. Taking the signal level up to acceptable levels will not fry the box. 2. It's a rental - who cares? 3. What do the signal levels look like in the diagnostic menu? |
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  frankpf3 verizon.net
join:2007-08-09 Huntington Station, NY
·Verizon FIOS
| 1.) Ok good point. 2.) Yes, it is a rental, but we all know how Verizon billing works. I don't feel like fighting with them because I received a new box and they are charging me for a damaged one. 3.) I am familiar with the diagnostics menu, but where does it show the signal level? |
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 knarf829
join:2007-06-02 | »cjhengineering.com/hdtv/cablehdt···diag.htm |
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  frankpf3 verizon.net
join:2007-08-09 Huntington Station, NY | Can we get to this menu on the moto boxes? I am used to the diagnostic menu that we normally see by hitting "select than menu". Doesn't look like this though... |
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 knarf829
join:2007-06-02 | It is a menu for the moto boxes, so of course you can.
The directions are right on the link. Of course, your IMG added an extra select, so it's Off - Select - Select |
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 DMS1
join:2005-04-06 Carrollton, TX
| reply to frankpf3 said by frankpf3 :3.) I am familiar with the diagnostics menu, but where does it show the signal level? It doesn't. What it does show is the signal to noise ratio and the AGC level, along with a rating for each (poor, fair or good). You want both to be "good". |
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 JMikeF
join:2005-05-05 Alexandria, VA
| reply to frankpf3 The POS Motorola HD-PVR receiver has a very low tolerance for signal strength that does not fall within a very narrow range. Most FIOS setups run hot with strong signals that can overload these boxes.
I'm hoping that Verizon will do the math and realize that the crap Moto boxes are costing them an arm and leg to support. One tech told me that Scientific Atlanta is working on a replacement.
It can't come soon enough. |
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 DMS1
join:2005-04-06 Carrollton, TX
| said by JMikeF :The POS Motorola HD-PVR receiver has a very low tolerance for signal strength that does not fall within a very narrow range. Most FIOS setups run hot with strong signals that can overload these boxes. I'm hoping that Verizon will do the math and realize that the crap Moto boxes are costing them an arm and leg to support. One tech told me that Scientific Atlanta is working on a replacement. It can't come soon enough. I'm not sure where you get your information from, but the QIP64xx series works with input levels of -12 to +15 dBmV for QAM256. I would not expect any vendor's hardware to support higher levels.
CATV aims to have a signal strength of close to +15 dBmV at the ground block. They do this by having the tap output level 3dB higher, knowing that a few hundred feet of drop cable will attenuate it down. The problem is that the ONT has the same output level, but is only a few feet away from the ground block. |
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  GeekGirl1 The Medium IS the Message Premium join:2007-01-28 Morrisville, PA
·Verizon FIOS
·Verizon Online DSL
edit: January 29th, @08:13PM
| reply to knarf829 said by knarf829 :The directions are right on the link. Of course, your IMG added an extra select, so it's Off - Select - Select Thanks! Was wondering how to access it. Works fine.
SNR (Signal to Noise Ratio) is under "D04 Inband Status".
I've got 37.4 dB SNR for my Comcast Sportsnet-HD channel (256-QAM). No errors. That's about 7 dB better than when I had Comcast cable. |
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  fiosanon101
@verizon.net | reply to frankpf3 Attenuators suck, if they are used they should be placed at the output of splitter. They seems to act up if they placed at the STB. |
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