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DocDrew
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join:2009-01-28
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DocDrew to antdude

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to antdude

Re: Is there a limited number of coax cable splitters that can be used?

Also realize most amps don't amplify the upstream channels, many just add more loss, like almost every one I've seen at a retail store.

YOU REALLY HAVE TO KNOW THE SIGNAL LEVELS FIRST.
DocDrew

DocDrew to antdude

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to antdude
said by antdude:

said by DocDrew:

1. How many devices actually need to be connected to the cable system?
2. How many are modems and cable boxes?

There is a TV in every room with their cable boxes (bye bye unencrypted QAM soon). Just one cable modem.

How many? I can't see your house.

antdude
Matrix Ant
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US

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antdude

Premium Member

said by DocDrew:

said by antdude:

said by DocDrew:

1. How many devices actually need to be connected to the cable system?
2. How many are modems and cable boxes?

There is a TV in every room with their cable boxes (bye bye unencrypted QAM soon). Just one cable modem.

How many? I can't see your house.

Here is an ugly drawings from an aerial shot if it helps: »zimage.com/~ant/ClientsH ··· rial.png Note that this might not be accurate especially with measurements, splitters found (might be more!), etc. I can't check my clients' house until maybe Sunday.
antdude

antdude to DocDrew

Premium Member

to DocDrew
said by DocDrew:

Also realize most amps don't amplify the upstream channels, many just add more loss, like almost every one I've seen at a retail store.

YOU REALLY HAVE TO KNOW THE SIGNAL LEVELS FIRST.

Interesting. FYI from last Sunday from the cable modem in the problematic very warm room after swapping rooms' external (not in the walls) coax cables and splitters without any amps:

RF Parameters
Downstream
Freq/Power: 693.000 MHz -16 dBmV
Signal to Noise Ratio: 30 dB
Modulation: QAM256
Upstream
Freq/Power: 30.700 MHz 53 dBmV
Channel Type: DOCSIS 2.0 (ATDMA)
Symbol Rate: 5120 kSym/sec
Modulation: QAM16

Status
System Uptime: 0 days 4h:10m:16s
Computers Detected: 1
CM Status: Telephony-AC Power Iso OFF Reg Complete
Time and Date: MON JUL 07 03:15:53 2014

DocDrew
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DocDrew to antdude

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to antdude
Yeah... that helps a little. So 5 rooms.

Room #1. No splitters, 1 connection
Room #2. No splitters, modem.
Room #3. A splitter. How many outlets on the splitter? How many devices connected?
Room #4. A splitter. How many outlets on the splitter? How many devices connected?
Family room. No splitter. 1 connection.

Attic has 2 splitters, next to each other? How many outputs on each?

So are there around 8 devices total?

antdude
Matrix Ant
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antdude

Premium Member

said by DocDrew:

Yeah... that helps a little. So 5 rooms.

Room #1. No splitters, 1 connection
Room #2. No splitters, modem.
Room #3. A splitter. How many outlets on the splitter? How many devices connected?
Room #4. A splitter. How many outlets on the splitter? How many devices connected?
Family room. No splitter. 1 connection.

Attic has 2 splitters, next to each other? How many outputs on each?

So are there around 8 devices total?

I will have to check again later since my brain isn't reliable. I know there are more in the attic, and they go all over the places and can be confusing. And then more in walls in each room with its own coax cable outlet. IIRC, bedrooms and office rooms share the same coax cable line and splitters and then more splitters. Ugh. Like I said, too many dang splitters and removing one in the problematic room fix the issues.

#1: TV, but might get a cable box/adapter later on. It is currently OTA (can't get all channels) though so that line was splitted from TWC.
#2: DVR and cable modem (phone and standard Internet packages). This room relies on room #4's coax cable with splitters.
#3: HDTV at the moment, but will need to get a box soon due to unencrypted QAM going away. Also, room #3 relies on room #2's coax cable line with splitters.
#4: Not connected to any devices yet, but plan to later on. This one has the main splitted coax cable lines to go to #2 and then #3.
Family room is mostly stable for its cable box (had Motorola DVR and regular boxes [past Motorola and current Arris]).

This is what I can remember off my brain's memory. :/

DocDrew
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DocDrew to antdude

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to antdude
Too low downstream @ -16, killing your SNR at 30.
Too high upstream @ 53

A local retail amp probably won't help and may make it worse. Best solution would be to remove splitters in the path. Being an eMTA it should be off the first split, hopefully a 2-way.

antdude
Matrix Ant
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antdude

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said by DocDrew:

Too low downstream @ -16, killing your SNR at 30.
Too high upstream @ 53

A local retail amp probably won't help and may make it worse. Best solution would be to remove splitters in the path. Being an eMTA it should be off the first split, hopefully a 2-way.

Hmm, first split would be a problem since that is in the attic. Ha.

DocDrew
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DocDrew

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said by antdude:

Hmm, first split would be a problem since that is in the attic. Ha.

Have any TWC techs recently been to that house to troubleshoot or install?

antdude
Matrix Ant
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antdude

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said by DocDrew:

said by antdude:

Hmm, first split would be a problem since that is in the attic. Ha.

Have any TWC techs recently been to that house to troubleshoot or install?

Two for installation a few summers ago. I know they detected low signals, but they fixed it during that time.

DocDrew
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DocDrew to antdude

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to antdude
Sounds like the cable comes in and splits to Family room and Room#4. Maybe 2-way split? 3.5db loss. Actually make that a 3-way to also feed room#1 too.

Room#4 has a 2-way splitter? 3.5db loss 1 outlet unused for room#4 and 1 outlet going to room #2.

Room#2 has a 3 splitter? 2 outs for the devices and 1 continues to room#3. 7dB loss for devices in room, 3.5db loss for room#3.

So the modem has maybe 14dB of splitter losses before it. With cable losses added signal at demarc is around +6dbmb downstream, 38dBmv upstream. SNR will probably be around 35-36db.

The cascaded splitters before the modem are the problem. You should try the modem in the family room, maybe room#4

antdude
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antdude

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said by DocDrew:

Sounds like the cable comes in and splits to Family room and Room#4. Maybe 2-way split? 3.5db loss

Room#4 has a 2-way splitter? 3.5db loss 1 outlet unused for room#4 and 1 outlet going to room #2. Actually make that a 3-way to also feed room#1 too.

Room#2 has a 3 splitter? 2 outs for the devices and 1 continues to room#3. 7dB loss for devices in room, 3.5db loss for room#3.

So the modem has maybe 14dB of splitter losses before it. With cable losses added signal at demarc is around +6dbmb downstream, 38dBmv upstream. SNR will probably be around 35-36db.

The cascaded splitters before the modem are the problem. You should try the modem in the family room, maybe room#4

It's not just the Internet and phone services. TV connection is affected as well like with HBO, BBCA, SyFy, etc. in the room #2. Removing a splitter before modem and TV improves the connected cable device when we tested them. They would like to keep stuff in there.

DocDrew
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DocDrew

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The DVR in room#2 has the same signal levels as the modem, which are all out of spec. It's the 3-way splitter to 2-way to 2-way that's the problem, it's 14db of downstream and upstream signal attenuation. Removing a 2-way split removes 3.5 db of losses which puts the signals just into spec.

antdude
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antdude

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said by DocDrew:

The DVR in room#2 has the same signal levels as the modem, which are all out of spec. It's the 3-way splitter to 2-way to 2-way that's the problem, it's 14db of downstream and upstream signal attenuation. Removing a 2-way split removes 3.5 db of losses which puts the signals just into spec.

Yeah, this needs to be fixed. So, would a good quality amp fix this issue before these splitters?

DocDrew
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DocDrew

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said by antdude:

Yeah, this needs to be fixed. So, would a good quality amp fix this issue before these splitters?

A 2-way active amp with 7-10dB gain could help. Installed in the location of the 2nd splitter with current wiring layout. This may cause issues with Whole Home DVR installs in the future though. Most amps also block MOCA networking used by such boxes. Something like this: »www.amazon.com/PCT-1-Por ··· 22RB36AJ

A call to TWC to fix the problems on the modem and DVR would probably be better, as they could rework the wiring layout.

antdude
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antdude

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said by DocDrew:

said by antdude:

Yeah, this needs to be fixed. So, would a good quality amp fix this issue before these splitters?

A 2-way active amp with 7-10dB gain could help. Installed in the location of the 2nd splitter with current wiring layout.

A call to TWC to fix the problems on the modem and DVR would probably be better, as they could rework the wiring layout.

Yeah, I suggested to them to get a TWC technician to fix it but they don't want them coming in again since they moved their stuff in. They got TWC set up when their new house was nearly empty. [sighs]
ITGeeks
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Cleveland, OH

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ITGeeks to antdude

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to antdude
No. That power adapter is for the DirecTV/Dish wholehouse network and powers an internal network with the the Dish.

antdude
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antdude

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said by ITGeeks:

No. That power adapter is for the DirecTV/Dish wholehouse network and powers an internal network with the the Dish.

Thanks, so it is useless for TWC stuff for signal strengths then.
antdude

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antdude

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Better splitters?

So, do you guys think it is worth trying better quality splitters (Monster and Monospace that were mentioned earlier)? If so, then are there any from the local retail stores (RadioShack, Best Buy, Costco, Walmart, Fry's Electronics, etc.) that can be returned easily? I found one Monster brand, but not the same as shown in Amazon link earlier: »www.frys.com/product/5654801 ... I don't think it is the same one?

DocDrew
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DocDrew

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The splitters you have are probably fine. Can't really be sure unless you post pictures of them though.

antdude
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antdude

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said by DocDrew:

The splitters you have are probably fine. Can't really be sure unless you post pictures of them though.

The new ones were from TWC. :/ Does that make any differences?

DocDrew
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DocDrew

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said by antdude:

said by DocDrew:

The splitters you have are probably fine. Can't really be sure unless you post pictures of them though.

The new ones were from TWC. :/ Does that make any differences?

The ones they use are good.

antdude
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antdude

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said by DocDrew:

said by antdude:

said by DocDrew:

The splitters you have are probably fine. Can't really be sure unless you post pictures of them though.

The new ones were from TWC. :/ Does that make any differences?

The ones they use are good.

Thanks. We won't bother then!
antdude

antdude

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Re: Is there a limited number of coax cable splitters that can be used?

Interesting. Symptoms seem to be worse when the weather is hot (e.g., 90F degrees), but not so bad when cooler like right now.

DocDrew
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DocDrew

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The signals drop a bit when it gets hot, due to cable expansion and an increase in resistance. Since they're already past acceptable specs and causing problems, they're just getting worse with the increased temps.

The house should really be rewired for better signal distribution.

antdude
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antdude

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OK, we replaced the other room's splitter and now things look better. We haven't see any channels going bad. I hope the cable modem signals are better too:

RF Parameters
Downstream
Freq/Power: 663.000 MHz -16 dBmV
Signal to Noise Ratio: 30 dB
Modulation: QAM256
Upstream
Freq/Power: 30.700 MHz 54 dBmV
Channel Type: DOCSIS 2.0 (ATDMA)
Symbol Rate: 5120 kSym/sec
Modulation: QAM16

Status
System Uptime: 6 days 5h:22m:44s

However, today is not a hot day (mid 80s F degrees).

DocDrew
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DocDrew

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Modem levels still suck. Borderline losing connection

It really should be rewired or redesigned.

antdude
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antdude

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said by DocDrew:

Modem levels still suck. Borderline losing connection

It really should be rewired or redesigned.

Wow, still? I am surprised TV, Internet, and phones are doing OK (no problems) lately. Hmm! What are the correct numbers? FAQ's numbers seem outdated. I wished these new Arris cable boxes would tell me their statistics like the former Motorola ones.

DocDrew
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DocDrew

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said by antdude:

said by DocDrew:

Modem levels still suck. Borderline losing connection

It really should be rewired or redesigned.

Wow, still? I am surprised TV, Internet, and phones are doing OK lately. Hmm! What are the correct numbers? FAQ's numbers seem outdated. I wished these new Arris cable boxes would tell me their statistics like the former Motorola ones.

In the Moto/Arris Navigator boxes, hold down the ok button for at least ten seconds and then press the down arrow for Guide diagnostics or the up arrow for box diagnostics.

Your signals barely work for single channels on upstream and downstream.

Downstream should be +12 to -12, with 33 snr or higher. Upstream shouldn't be higher than 51. A 3 db margin would be better to account for normal signal variance. The levels have gotten tighter due to multiple channels both ways and higher modulation rates on the upstream channels.

antdude
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antdude

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In the Moto/Arris Navigator boxes, hold down the ok button for at least ten seconds and then press the down arrow for Guide diagnostics or the up arrow for box diagnostics...

Finally I have the nice technical data I was looking for, and I didn't have to power off the box to see with holding down the OK button for 10/ten seconds (saw its blinking mail icon on DVR)!

I assume it is box diagonstics for signal readings:
inbound quality (PWR, SNR): -15.10 dBmV (red) 33.70 dB (green)
inbound quality-2 (PWR, SNR): -14.10 dBmV (yellow) 33.00 dB (red)
OOB FDC RF Quality (PWR, SNR): -14.70 dBmV (yellow) 34.90 dB (green)
This was on channel 482 (MAXE-HD). I assume different channels will have different data?