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HunterZ

join:2003-07-16
Kent, WA

1 edit
reply to HunterZ

Re: [Signals] Just moved and need some advice

Update: With cable -> amp -> family room -> 2-way splitter -> modem and TV, I am consistently getting around 20 mbps down and 5+ mbps up. This is as good of performance as I was getting when connected directly to the line in the garage. I guess being able to bond 4 channels down and 2 up is enough to make up for needing the amplifier to reach 0 dBmV (which is exactly where the downstream power level is at).

I think I'm going to live with the connection as-is for now, since I don't expect to be able to get better performance from correcting it. I will continue to monitor stability and speed, though.


ropeguru
Premium
join:2001-01-25
Mechanicsville, VA
What you really need to do is get a truck roll and have Comcast come out and get the ball rolling to get the levels adjusted without the AMP.


HunterZ

join:2003-07-16
Kent, WA
Is it normal for house wiring to cause a -8 dBmV drop? Since I'm getting -4 dBmV at the line from Comcast, I'm concerned that they're going to blow me off by saying that that is good enough and that the house wiring is my problem.

rody_44
Premium
join:2004-02-20
Quakertown, PA
Reviews:
·Comcast

1 edit
No -4 isnt normal. But we still dont know the actual signal. I believe that thing marked Amp is nothing but a splice connector. Open that up and that is where the actual comcast signal would be. Thats if im reading the picture correctly. Its not out of the question that a piece of bad coax only a few feet long loses 15 dbs. Even the piece as short as the one going from outside to iinside your garage. The piece at the outside is what is important in comcasts eyes.

rody_44
Premium
join:2004-02-20
Quakertown, PA
Reviews:
·Comcast

1 edit
reply to HunterZ
The cable both in your family room and at the amp in the garage look to me like some premade cables you buy at a home improvement store judging by the ends. All the cables outside have ends that would be typical of cable company installed cables. So im guessing all your cables are homeowner installed and the cable company simply put ends on the ones outside. I dont see your cable bonded at all. Not good, especially with a modem.


HunterZ

join:2003-07-16
Kent, WA
said by rody_44:

I believe that thing marked Amp is nothing but a splice connector. Open that up and that is where the actual comcast signal would be.

I'll try to do that when I get a chance. I did take a closer look and found that it is actually a hard plastic case that may not be easy to open, as it appears to snap together with tabs. It doesn't look like opening it will be as trivial as I'd hope.

said by rody_44:

Its not out of the question that a piece of bad coax only a few feet long loses 15 dbs. Even the piece as short as the one going from outside to iinside your garage. The piece at the outside is what is important in comcasts eyes.

As I mentioned before, I get power levels of -4 dBmV just inside the garage, so I'm likely not losing more than 4 dB in the couple of feet between the splice and the inside of the garage. I definitely want to check what signal levels I can get at the splice, though.

said by rody_44:

So im guessing all your cables are homeowner installed and the cable company simply put ends on the ones outside.

This was my guess as well; it's good to get confirmation.

said by rody_44:

I dont see your cable bonded at all. Not good, especially with a modem.

I would have expected at least the splitter to be grounded, but it isn't. The "Amp" case is lashed to the telephone conduit with a plastic zip-tie, and is not electrically connected to the conduit or anything else as far as I can tell.

My house electrical mains come from underground, and connect to the meter box via a conduit. I'm a bit uncertain about where I can get an optimal ground connection from, although I see a few possibilities (also refer to pictures below):

1. A copper wire (I think; it's covered in stupid house paint too) with green plastic shielding/insulation that appears to come out of the ground and is not connected to anything on the end I can see. It looks like this could be it; since I don't want to use an exterior coax splitter, should I instead purchase and install a coax ground block between the splice point and attach the green wire to it? Can I verify that the green wire is grounded by touching an ohmmeter to it and to, say, my electrical mains conduit or what I think may be the ground rod?

2. A twisted steel cable of the type I've often seen attached to ground rods with a clamp/electrode. It comes from the ground near the green wire and immediately disappears up under the siding. I suspect this may run to the breaker box in the garage or something.

3. A metal rod (possibly zinc or steel, although it looks a bit rusted on the very top) protruding just a couple inches from the ground, with no electrode/clamp attached. Could this be the ground rod, with everything connecting underground? It does look like the green wire and twisted steel cable come out of the ground just a few inches away, on the house side of the rod.

4. The natural gas meter conduit on the opposite end of the wall has some wires attached to it that come out of the ground right next to it.

Here are some more pictures in case they help:
- Closeup of possible ground connections: »docs.google.com/open?id=0BwvZzVl···obWZuUGM - note the twisted steel cable near the top left, green wire near top middle, and rod at lower left
- Wider shot of electrical/cable/telephone area: »docs.google.com/open?id=0BwvZzVl···ETGg4eVk - large conduit on left is electrical mains (with meter at the top), small conduit next to it goes to an RV power outlet, and rightmost conduit goes to telephone connection box. Cable comes from underground near the telephone conduit, and splice box is lashed to the same conduit.
- Even wider shot of the above, showing the electrical meter: »docs.google.com/open?id=0BwvZzVl···UZ1REVTQ
- Even wider shot of west side of house, with gas meter on right and electrical/cable/telephone on left: »docs.google.com/open?id=0BwvZzVl···YZFpvTnM


retiredqwest

join:2005-04-01
Spokane, WA
quote:
1. A copper wire (I think; it's covered in stupid house paint too) with green plastic shielding/insulation that appears to come out of the ground and is not connected to anything on the end I can see. It looks like this could be it; since I don't want to use an exterior coax splitter, should I instead purchase and install a coax ground block between the splice point and attach the green wire to it? Can I verify that the green wire is grounded by touching an ohmmeter to it and to, say, my electrical mains conduit or what I think may be the ground rod?

That is probably the ground wire that may have been attached to the coax ground block. Telco and CATV use a #6 wire w/green insulation for that purpose.

Using a Multimeter, set it on AC Voltage FIRST and test the wire. Then test it using the ohms scale.

quote:
2. A twisted steel cable of the type I've often seen attached to ground rods with a clamp/electrode. It comes from the ground near the green wire and immediately disappears up under the siding. I suspect this may run to the breaker box in the garage or something.

That is probably the power ground to the breaker panel.

quote:
3. A metal rod (possibly zinc or steel, although it looks a bit rusted on the very top) protruding just a couple inches from the ground, with no electrode/clamp attached. Could this be the ground rod, with everything connecting underground? It does look like the green wire and twisted steel cable come out of the ground just a few inches away, on the house side of the rod.
That is a 6-8' ground rod, if you dig down there should be 3 connections attached to it. CATV, Power, and Telco attach to it to make a 'common' ground.

quote:
4. The natural gas meter conduit on the opposite end of the wall has some wires attached to it that come out of the ground right next to it.

Those are used to attach a cable locator, since the pipe below the ground is plastic to the street.

IMO, you should make Comcast come out and fix that mess. You really shouldn't have to fix things and legally they are responsible to make sure that the coax has adequate grounding at your premises.

You may also want to consider rewiring the entire house. Ya, I saw you mentioned a crawl space..... If you wire the house and do what we call a 'home run' with each outlet you could probably eliminate most of the splitters you have now and maybe even the AMP. It all depends if you have the time and how long you think you are going to stay in that house if you want to make the effort.


HunterZ

join:2003-07-16
Kent, WA
Thanks, I'll contact Comcast about having a grounding block installed on the tap.

I'm not a huge fan of crawlspaces (especially ones that previously had mice in them), but I think I should really run a new 25-30 foot cable from the outside of the house down into the crawlspace and over to the family room. Are there any good options for having someone else do this without paying an arm and a leg?

I also really don't want to re-wire the whole house at this time; I just want to have both the TV and Internet service in the family room (I already have wifi and HomePlug AV equipment to distribute the LAN/WAN throughout the house), and we currently have no plans to use TVs anywhere else in the house.


retiredqwest

join:2005-04-01
Spokane, WA
I think you might be hard pressed to find someone willing to do the crawlspace thing on the cheap. Especially concerning mice and Hanta Virus.

The Comcast tech will more than likely not be interested in doing it either... but it won't hurt to ask how much to install the line.

He might be willing to provide the RG6 cable for free. So, if you get the cable placed they will come back and install the connectors for free.

Is it possible to get close enough to the family room on the outside of the house?

On Craigslist, there's some guy in Kirkland who will install coax for a $1 a foot....8)


HunterZ

join:2003-07-16
Kent, WA

1 edit
I'm actually a bit confused about where the current line to the family room is installed; it goes into a hole in the garage wall and then disappears, but my understanding is that it's not likely that there is crawlspace under the concrete-floored 3-car garage. I think there's a vent in the foundation on that side of the house, though, so I guess there must be a space under it?

Going around the outside wouldn't work too well, but I have been thinking of an alternative: the built-in entertainment center shares a wall with the garage, so I could drill into the garage by going right through the back of the existing cable hole. I could then tack up RG6 around the garage to where the existing cable comes in. This would involve going over a door and behind the tankless water heater and furnace, but I don't think any of that would be too dicey.