• Some people think that antenna/satellite tv coax wiring in a room causes interference with the operation of a wi-fi network.
    I think it has absolutely no effect, but I want to get confirmation from the experts in this forum.

  • TV frequencies are well below 802.11 frequencies.

    highest broadcast frequency: 801.25, less than 1/3 802.11 frequency

    CATV channel PPP: 547.25, less than 1/4 802.11 frequency

    these are American frequencies.

    Third and fourth harmonics of signals meant for a receiver are not going to bother 802.11 equipment

  • how about this:
    "Sources of Interference for AirPort" says:

    "Direct Satellite Service (DSS) RF leakage: The coax cable that came with certain types of satellite dishes may cause interference. Obtain newer cables if you suspect RF leakage."

    Can this be verified with a spectrum analyzer?

  • Can this be verified with a spectrum analyzer?

    Yes, that's what spectrum analyzers do. I tend to think of spectrum analyzers as big delicate boxes that cost $70,000 and require advanced knowledge to operate and analyze.

    Is the satellite box within inches of the network antennas?

  • OK, changing hat for a moment.

    As a certified sat engineer and sat technologies trainer...

    First thing is get hold of WiSpy, it's very cheap and is a fantastic spectrum analyser that will clear up any doubt about interference.

    The second point is that I have never encountered SAT frequencies near the ISM or UNII bands for VSAT or SAT TV downlink, nor in the intermediate frequencies between the antenna and the decoder/modem or whatever other device in line.

    I had a look at the Direct Sat technical specs, and there are references to local oscillators that operate
    nominally from 1900MHz to 3000MHz, which is then divided
    by two to provide 950MHz to 1500MHz. A second signal
    operates nominally from 1400MHz to 2150MHz. This falls some way short of the 2.4 we know and love.

    So a leak from the LO is theoretically possible (wahay, thanks apple for pointing it out), but I have to say, I would SERIOUSLY doubt you will EVER see it.

    But splash a couple of hundred bucks and get WiSpy, if you are serious about wireless networking you can not do without it.

    It will also remove any doubt about interference.

    Neil Mac

  • I would agree that it is not a likely issue. I have done several spectrum sweeps of my house I(which had satellite before Fios) and the only issue I have found is cordless phones that are marketed as 5 GHz and that use 2.4 GHz too! You have to read real close in the phone documentation to get the real "truth".


  • Thank you all for the useful information. There is always so much to learn from everyone on these forums.

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