CATV amplifier recommendation needed.

Discussion in 'Cable TV Discussion' started by Brian F., Mar 29, 2019.

  1. Brian F.

    Brian F. New Member

    Mar 29, 2019
    PROBLEM: Many channels not available on 2 set top boxes, but ok on other two. FOC RF Quality low issue?

    Provider: Spectrum TV (Central Florida, used to be Brighthouse Cable)

    I have 4 set top boxes, 1 digital adaptor box and 1 cable modem in my house. I use an outside splitter for individual coax runs to all. In one room I am using a Bright House provided amplifier/splitter (+4 db gain on both outputs) for one input and 2 outs to the set top boxes in that room. That used to work fine, but now on these 2 boxes I frequently cannot get channels above 1100 to come in at all. Even after sending a refresh signal to them many times. I have tried using just a plain 1-to-2 splitter with no amplification and the problem was the same. I even swapped a working box with one that could not lock on channels and the same thing happened on the box I know is good. The CATV amp is powered up, but the cable box diagnostics show a pathetically low signal for the following..
    FDC RF Quality (PWR,SNR) -13.80 dBmV, 34.1 dB (This item is highlighted in YELLOW)

    On the boxes that work perfectly that same setting shows..
    FDC RF Quality (PWR,SNR) -8.6 dBmV, 36.2 dB (This item is highlighted in GREEN)

    So, do I just need a more powerful CATV amplifier in front of the 2 problematic boxes or what? And where? The current CATV Amp is 1 foot before both cable TV boxes. The cable runs from outside to the amp currently in use is about 80 feet. Should an Amplifier be placed at the start of the cable run instead of near the CATV set-top boxes. Obviously the signal-to-noise level is comparable with the only difference being the PWR on the bad boxes being 5 or more dB lower than the working boxes.

    Any guidance on CATV Coax Amp brands/models, forward and reverse gain I should look for, and placement is greatly appreciated.

    (I have screenshots GoodReceptionBox.jpg BadReceptionBox.jpg of both the good box summary and the bad box summary statistics)[​IMG]
    Last edited: Mar 29, 2019
  2. scooper

    scooper Hall Of Fame

    Apr 22, 2002
    Kansas City KS
    What you need to do is call the cable company for a truck roll so they can fix it properly.
  3. Brian F.

    Brian F. New Member

    Mar 29, 2019
    I wish it were that easy. The last time they got called for a similar problem they insisted on more provisioning triggers, box swaps, and eventually the came out and said, oh, it must be your cables... (Its not) and wanted me to pay them $200 to run a 80 foot Coax cable outside my house along side all my other wires. I'm pretty sure an amp will take care of it, just not sure what models are good and if It should be right near the cable converters or at the junction box outside. CableMaster seems to have good ones, but I see reviews of them dying about 1 month after purchase.
  4. KyL416

    KyL416 Hall Of Fame

    Nov 10, 2005
    Tobyhanna, PA
    Amps are garbage in garbage out. If there's noise on certain frequencies to the point where it can't see the difference between the 0s and 1s, it will just amplify that noise. They can also cause problems for things that require two way communication. They're only good for really long runs where the incoming signal is otherwise clean.

    Also, digital is virtual channels. You'll need to enter the diagnostic menu while you are tuned to one of those problem channels to see the actual physical channel number and frequency they originate from. It should be on a screen that also lists things like VPIDs and APIDs. If your box doesn't have a diagnostic screen for that, you might have to get a cheap QAM USB tuner, and connect a cable with the bad signal and see which frequencies are giving you a lot of errors in TSReader.

    If your cable company is now using some of the higher frequencies, older cables won't cut it, and older splitters not rated for 1 GHz or higher will cause problems too. You might also have to switch to quad shield RG6 if you have a noise or interference issue. Like a nearby TV or FM tower, airport or a motor from something like a computer's fan can cause problems on frequencies in the VHF range and some harmonic frequencies, and all an amplifier will do is just boost that interfering signal. Electronics with poor shielding on their power supply can cause RF interference too, like cheap LED lights.

    If you can, also trace the run of each cable, things like pinching because of a staple or fastener or if it got wedged between beams and HVAC ducts can create problems too.
    Last edited: Mar 29, 2019
  5. P Smith

    P Smith Mr. FixAnything

    Jul 25, 2002
    W.Mdtrn Sea
    Agree with KyL416, adding to that, personally I would use standalone spectrum analyzer and will stop at each point to do measuring SNR - at antenna, splitters/amplifiers, etc
    Before adding anything to existing setup.

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