I have a long run from the pole to my house, so the cable company installed a repeater. After doing some research I'm starting to see that I'm still not getting the full signal strength to my Main TV and My Cable Modem.

Here is what I have now:

enter image description here

the two things I'd like to accomplish are

1 - get the best signal possible to my Main TV and to my Cable Modem

2 - Add one more TV

So here is what I was thinking should work:

enter image description here

Please let me know your thoughts on this approach or if there is a better way to do it.



UPDATE 5/19/2015 12:47 am EST

Here are the current results from my modem:

Downstream Bonded Channels

Channel Lock Status Modulation Channel ID Frequency Power SNR Corrected
1 Locked QAM256 1 651000000 Hz 3.6 dBmV 38.8 dB 6238 3004 
2 Locked QAM256 2 657000000 Hz 3.3 dBmV 38.6 dB 5254 2258 
3 Locked QAM256 3 663000000 Hz 3.2 dBmV 38.5 dB 4282 1875 
4 Locked QAM256 4 669000000 Hz 3.3 dBmV 38.5 dB 3444 1327 
5 Locked QAM256 5 675000000 Hz 2.9 dBmV 38.1 dB 4326 1508 
6 Locked QAM256 6 681000000 Hz 2.9 dBmV 38.4 dB 4995 2056 
7 Locked QAM256 7 687000000 Hz 2.8 dBmV 38.4 dB 5716 2352 
8 Locked QAM256 8 693000000 Hz 2.6 dBmV 38.3 dB 7679 4029 

Upstream Bonded Channels

Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power 
1 Locked ATDMA 10 5120 Ksym/sec 36500000 Hz 45.5 dBmV 
2 Locked ATDMA 11 5120 Ksym/sec 30100000 Hz 45.0 dBmV 
3 Locked ATDMA 12 5120 Ksym/sec 23700000 Hz 44.5 dBmV 
  • With 3 amplifiers, I wouldn't be surprised if the cable company came knocking on your door. You will likely throw off a huge amount of noise into the system and might impact other customers. – Steven May 20 '15 at 1:07
  • Note that putting a splitter first REDUCES the (already weak) signal into your "wall of amplifiers." You want an amplifier as the first thing your weak signal sees. – Ecnerwal May 25 '15 at 0:41

Before going crazy adding amplifiers you might want to spend a little time investigating the current wiring/splitting situation in your house, if you haven't already.

Every splitter and every foot of cable contribute to signal loss:

  • Verify that you have only the bare minimum number of splitters in your system (in this case it seems like you can get away with 1).
  • Make sure you don't have any unnecessary long bundles of cable, or cable splices. Sometimes people will buy a long amount of cable and then just coil it all up in the basement instead of trimming it.
  • Make sure all your existing cables are in good condition: no nicks in the jacket, hard kinks (a bend is fine but a hard kink can break the interior insulation). Make sure all connections are secure. If any cable or connector seems questionable, replace it.
  • Make sure the splitter only has as many outputs as you need. A 4-way splitter will drop the signal on each leg more than a 3-way, no matter how many devices are plugged in.

If you're trying to troubleshoot signal strength, you may be able to use the config page on your DOCSIS modem, which should display the signal strength ("power level" in dBmV and "signal-to-noise ratio" in dB).

I think it's unlikely you'll really need 3 amplifiers in your house, especially if the cable company has verified that their own amplifier is providing a sufficient signal to your property. Typically the utility company is responsible for getting a usable signal as far as the exterior wall. If the above suggestions don't yield anything, you might want to call them back and ask them.

Edit based on additional cable modem signal info

The signal numbers you've posted all look perfectly within spec according to several websites, e.g. What cable modem signal levels are considered good?. I am not a cable tech and there may be other signal issues in play but as a rough cut you seem to be getting a decent signal. I don't think an amp will help.

I assume you're using a site like Speedtest.net to measure your internet speed and you're not getting what you think you should?

There are a couple reasons this might happen:

  • Poor signal to cable modem (I think we can probably rule this out, but who knows)
  • Poor wifi signal, if you're using wifi. Make sure you do these test with a hardwired ethernet cable if possible, to remove that variable.
  • Competition between other internet users in your area. Peak internet usage is between 7-9pm. Try running a test late at night or early in the morning to see if you get a different result.
  • Unsupported cable modem: is your cable modem provided by your utility or did you buy it yourself? Is it an approved model? You mention "DOCSIS 3" in your post so I assume you've thought about this, but make sure you have an approved modem that supports your utility's network.
  • Some other issue with your cable provider

To test whether your house's wiring / splitters are the problem, try moving the cable modem to be directly connected to the utility-installed amplifier (i.e. remove all the household wiring and splitters), and see if you get different speed or signal numbers.

  • I can't format my response very well in the comments, So I added it to my original post.. – mreinsmith May 19 '15 at 4:46
  • Oh I also forgot to mention the run to my house is about 400 ft – mreinsmith May 19 '15 at 4:54
  • @mreinsmith: I'm not a cable tech but those seem like solid numbers to me, based on some checking online. I'm not sure adding an amplifier will help. What specifically is wrong with your internet? – Hank May 19 '15 at 4:55
  • It's a long story, to summarize we've never seen the speeds they've promised and I want the numbers to prove it. I haven't pushed the issue yet because I'm doing some remodeling and I relocated several of these connections and replaced the cable. I'm also concerned that when they originally installed the repeater that they only did the minimum to make it work. We always have problems with slow response on the TV cable box. So now I'm to the point where I can do the connections right and I want to make sure I've got the best signal possible and not just adequate. See where I'm coming from? – mreinsmith May 19 '15 at 5:13
  • @mreinsmith: I added some more info to my answer. I'm not convinced you have a signal problem. – Hank May 19 '15 at 22:37

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