I'm looking for tools that can help me test the signal coming into my house from my cable provider. I am currently having issues with a Leviton CATV Relay which I'll replace, but I've been having issues with the cable modem since I took it offline.

I now realized, after reading the manual on Leviton's site, that the relay is actually a two way amplifier, which I presume could have previously been affecting the signal coming into the modem, and the modem was probably calibrated to handle it as it was.

Anyway, that's neither here nor there, I'm hoping once the relay is replaced it will normalize the modem, but I still would like to know what tools I can get to test the stability of the signals coming in (or being relayed out).


You can use your cable modem itself as the tool. Do a search for "[your modem manufacturer] cable modem diagnostics" and you'll find out how to access the modem's diagnostic page in a web browser. This will give you upstream & downstream signal levels and lots of other useful info.

Here's a page with some information about a few different manufacturers.

  • I've been monitoring the modem (for months), and the new one I have (Motorola SB6120) has a DSNR: 37dB and DPL: 0-2dBmV which is within norm, upstream is a bit off @ 46dB where I know my ISP likes it between 38 and 45 dB...
    – Gup3rSuR4c
    Sep 23 '10 at 19:06
  • Then I'd be handing this one off to the cable company techs if I were you. This sounds like it's their problem to fix, not yours. Sep 24 '10 at 2:57

I'm afraid any stand alone meters are going to be pricey. There are two types to measure RF signal level. One that you set on a frequency and read the power level at that frequency. The other is called a spectrum analyzer and shows a waveform of the power level across a range of requencies. That is what is really needed to see whats going on. I'd try to get by with cable modem as suggested above.


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