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RedBatman
join:2014-12-23

RedBatman

Member

[Signals] Power Levels

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So I was checking my Power Levels on my Modem today since I have been having reboots from my modem more recently. My mid Upstream Power level is 50 and I have been told that is not good, should I call Comcast soon?

PS. I have no splitter going to my modem its a cable going straight to a coax outlet.

maxbrando
Premium Member
join:2014-06-01

maxbrando

Premium Member

nevermind

Streetlight
join:2005-11-07
Colorado Springs, CO

1 edit

Streetlight to RedBatman

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to RedBatman
Your downstream signals are near perfect but adding a two-way splitter would decrease the downstream signal and increase the upstream signals by ~3 dBmV. That wouldn't be bad for your downstream signal but upstream might go out of spec and your internet could become unstable or drop out completely. Your upstream signals are within spec but one of them is on the edge of being too high. If the temperature increases substantially it may go out of spec. If you have problems with Internet dropping out, I'd call Comcast and have an on site tech find out why your upstream signals are so high. You should first look at the condition of all coaxial cable fittings and make sure they're not corroded or lose and check the cables for damage.
RedBatman
join:2014-12-23

RedBatman

Member

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Where I live its very cold right now, as for the cable its only about three years old right now. But yeah I will give Comcast a call very soon.

But Here is another photo too.

Streetlight
join:2005-11-07
Colorado Springs, CO

Streetlight

Member

Download power levels are ideal. They can be negative and different folks in these forums have somewhat different opinions about the range of values that are acceptable which depend on the QAM number. Some will say it is ok if between -10 dBmV to +10 dBmV, others say -12 to + 12, etc. Zero dBmV is ideal.

There have been similar discussion about what is acceptable signal levels for upstream values. You haven't indicated where you live, but if it's zero deg F or lower and goes to, say +50 deg F, you might find upstream Channel 57 going to higher than 51 dBmV and then run into trouble. By the way, in eastern Colorado where I live, this does happen! There's a saying here: You know you're in Colorado if you switch from Heat to AC...on the same day.

Check out the following link for more information:

»Comcast High Speed Internet FAQ »What should my Signal Levels be?

You should check the condition of the cable connectors and the cable itself. One lose connector could be the problem.

Mike Wolf
join:2009-05-24
Tuckerton, NJ

2 edits

Mike Wolf to RedBatman

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To be honest, I'm seeing those exact same power levels on my downstream channels and upstream channels and haven't had any problems the 13 days (to date) that my 6183 has been in service, and I'm in the North East so the temperature hasn't gone above 34°F for awhile, the average being around 10°F. I know some people mentioned to me the upstream channels on mine are borderline between 47 and 49 dBmV and that I might see problems when it gets warmer out, but I ran it past an engineer and he said it was fine. I'll keep an eye on it but if I'm not having performance problems I'm not worried.

owlyn
MVM
join:2004-06-05
Newtown, PA

owlyn

MVM

It it's partially a function of how well the tap and node are configured. My US had been around 47- 47.5 in the winter and it didn't go up in the summer.
RedBatman
join:2014-12-23

RedBatman to Streetlight

Member

to Streetlight
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Well I live in MD and it is 10 degrees right no XD.

Also another update.

owlyn
MVM
join:2004-06-05
Newtown, PA

1 recommendation

owlyn

MVM

Your US level on the middle channel is at the edge of acceptable. Any higher and you will probably lose bonding and reboot.

Mike Wolf
join:2009-05-24
Tuckerton, NJ

Mike Wolf to owlyn

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to owlyn
I guess I'll find out in six to seven months. Thanks for the info

cc6141
@comcastbusiness.net

cc6141

Anon

I also live in MD, and I find the upstream power on my 6141 varies between 48-51 on the hottest summer days, and mid 40s to high 40s in the winter.

Pretty sure there are splitters in the walls that are causing the slightly high upstream, but it's a rental house and it seems to work fine so there's not much I can do.
RedBatman
join:2014-12-23

RedBatman

Member

Well I'm still doing fine but that one number in the middle goes to 50-51 still. Should I call Comcast and have them come over, or should I just wait for it to get warmer?

owlyn
MVM
join:2004-06-05
Newtown, PA

1 recommendation

owlyn

MVM

Have someone come out. It will go higher when it gets warmer.
JoeHemi
join:2011-05-06
united state

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Many times, its better not to call. If you aren't experiencing service issues now, I wouldn't risk having someone come out and "fix" the issue but possibly cause another.

Johkal
Cool Cat
MVM
join:2002-11-13
Pennsyltucky

1 recommendation

Johkal

MVM

said by JoeHemi:

Many times, its better not to call. If you aren't experiencing service issues now, I wouldn't risk having someone come out and "fix" the issue but possibly cause another.

I would have to disagree.
I don't want my signals at the top or bottom of any max spec range. I enjoy stability 24/7 and don't want to deal with temperature variation causing a maxed signal level to slide out of range and I start having connection issues.

Silly analogy: If you have a lump under your skin that won't go away but it isn't painful, do you wait until it gets bigger and maybe cancer or do you get it checked out by a doctor just to make sure?
JoeHemi
join:2011-05-06
united state

JoeHemi

Member

said by Johkal:

I would have to disagree.
I don't want my signals at the top or bottom of any max spec range. I enjoy stability 24/7 and don't want to deal with temperature variation causing a maxed signal level to slide out of range and I start having connection issues.

I get it, but all I'm saying is generally in the cable tv biz, if its not broke don't fix it.
At the very least, the OP should take the modem to the groundblock just to verify there aren't any hidden splitters and then post the results. I would rule out any problem within the house unless paying for a truck roll is more desirable.

Johkal
Cool Cat
MVM
join:2002-11-13
Pennsyltucky

Johkal

MVM

As the OP state: "PS. I have no splitter going to my modem its a cable going straight to a coax outlet."

Start there.
JoeHemi
join:2011-05-06
united state

JoeHemi

Member

Yeah, pretty unlikely he doesn't at least have a splitter on the outside of his house. But hey, maybe the installer ran the cable from the tap straight to his outlet! lol

Johkal
Cool Cat
MVM
join:2002-11-13
Pennsyltucky

Johkal

MVM

OP needs to clarify his exact setup.
RedBatman
join:2014-12-23

1 recommendation

RedBatman

Member

Well Basically its the cable that goes to my modem goes straight to a coax outlet. Nothing in between just straight to the outlet. Anyways the technician is coming out tomorrow so it will be fixed then.
bleagh
join:2004-03-11
Salt Lake City, UT

bleagh to RedBatman

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I'm using a leased xfinity TG862G (Arris wireless gateway).
I just have internet only (Blast 105/10), so have been connection directly to the cable outlet (no splitter).

My downstream levels have been 34-36 dB (most a bit above 35) with power levels -2 to -4 dBmV.
Upstream power levels were usually from 49 to 51.50 dBmV, although today they were 50-52.25.

After just over 2 weeks I have NOT had any problems with the internet at all, so haven't worried about it.

The self install kit I got came with a splitter and an extra cable, so today I decided to install the splitter to see what happens.

With the splitter:
Downstream SNR levels are still 34-36 dB (although now most are below 35), but power levels are now -5 to -7 dBmV.
Upstream power levels are now all 53.00 dBmV (I guess that is as high as it will go).

So far the connection still seems okay (even though the upstream power levels are clearly not that great). But I've only used it for some speed tests, ping tests, and some minor internet browsing.

If I decide to keep this I will likely buy my own modem. So I am not sure if I should have anything done now, or just wait till I get a new modem and see how it is then.

owlyn
MVM
join:2004-06-05
Newtown, PA

owlyn

MVM

Get it fixed before you get your own modem. Comcast will blame your modem. You definitely have an upstream power problem.

Mike Wolf
join:2009-05-24
Tuckerton, NJ

4 edits

Mike Wolf

Member

Alright I actually started getting problems with my modem losing it's upstream and not being able to reaquire, and having no internet intermittently the past few days as the upstream power level was going up to 51 dBmV, so I had a tech come out today and we checked the upstream power from the tap which was 31.5 dBmV to the aerial drop which was 40.2 dBmV to the first splitter which was 45.1 dBmV. He checked fittings, couplers, cables, ground blocks, and checked for noise. He installed an AquaTight fitting at the tap and he ran a new cable to the modem to take out a splitter and everything looks good right now at 46.8 dBmV 46.3 dBmV and 46.5 dBmV for the three upstream channels. It's 37°F by me as of this post.

The reason why I made this post was to share my own experience with similar power levels and the steps that were taken to fix it. The tech that came out by me and the senior tech who he called recommended having a zero loss amp installed or minimize as many redundant splitters as possible. Hope this helps someone.
Expand your moderator at work

owlyn
MVM
join:2004-06-05
Newtown, PA
Netgear CM2050V
Netgear RBRE960
Netgear RBSE960

owlyn to Mike Wolf

MVM

to Mike Wolf

Re: [Signals] Power Levels

Those levels should be okay, but unless it is a long run from the drop to the splitter, there is a lot of loss. It depends on the cable they used, the length, and the frequency, but I suspect that loss is twice what it should be. See this: »Cable Modems and Wiring Issues »Chart of Signal Loss per 100ft

Mike Wolf
join:2009-05-24
Tuckerton, NJ

4 edits

Mike Wolf

Member

Yeah I thought it seemed strange but the tech said that was normal. The distance from the ground block to the first splitter is about 15 to 20 feet using an unmarked white coax cable using a PPC AquaTight connector on one end which is connected to the ground block outside and a PPC EX6 connector on the other. That goes into an Antronix 2 port 3.5dB per port splitter, one peg goes to the modem using a CommScope F677TSVV cable »www.commscope.com/catalo ··· id=46893 which I'm guessing is between 40 to 50 feet long and the other peg goes to a three way splitter. Frequency is 23700000 Hz at 46.5 dBmV 36500000 Hz at 46.3 dBmV and 30100000 Hz at 46.8 dBmV.

owlyn
MVM
join:2004-06-05
Newtown, PA

owlyn

MVM

It's the distance from the tap to the ground block that I am concerned about. I suspect there is too much loss there.

Mike Wolf
join:2009-05-24
Tuckerton, NJ

1 edit

Mike Wolf

Member

Oh ok, you had me confused when you said splitter. Yeah, like I said it seemed strange to me but the tech said it was normal, and it's only two years old. It was in the 20's yesterday, and I mentioned "suck out" being a concern but he said the home health checks he performed were all in the green. I'll measure the distance later today.
Mike Wolf

Mike Wolf

Member

My neighbor next door on a different tap had phone issues with their XB3 yesterday and today so a tech came out this afternoon. When he was done with them he checked my signals at the ground block and said it was reading 42.2 dBmV. He said it was really good since the aerial drop is 70 feet long. He also said that Comcast "desperately needs to do major work" in my area because the "techs have been running ragged" fixing problems with signals and equipment, whatever that means.