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ATSC Frequencies?

IshlachiIshlachi Junior MemberPosts: 34
Has anyone seen a list of frequencies out there for the new ATSC channels? Also, any recommendations on a spectrum meter to measure both NTSC and ATSC channels?

Thanks

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  • ericmedleyericmedley Senior Member - 4000+ posts Posts: 4,177
    Ishlachi wrote: »
    Has anyone seen a list of frequencies out there for the new ATSC channels? Also, any recommendations on a spectrum meter to measure both NTSC and ATSC channels?

    Thanks

    Channels 2-51 will be used. As of Feb 2009, stations will be able to switch over to full power Digital broadcast. For those who are suffering with spotty digital OTA (myself included) that day will end the problems.

    The bands range from 54-210mhz (ch 2-13) 210-698mhz (13-51)

    This will free up from 850mhz-roughly 1010mhz. The cell phone companies are already squatting on this territory hoping to get some more air space.
  • TurnipTruckTurnipTruck Junior Member Posts: 1,485
    The over-the-air digital signals fall on the same frequencies that the analogs did. Some of the upper allocations are no longer being used. Don't forget that cable TV channel numbers don't match in frequency with over-the-air.

    As far as a signal meter, a Sadelco DisplayMax would work for you. An analog spectrum analyzer will not give you accurate power levels on digital carriers. Over the air digital signals are modulated in 8VSB. Be sure any signal meter makes reference to it.

    Look on Blonder-Tongue's website for their Broadband Guide. It's a downloadable pdf that give you lots of good MATV/CATV system information. It also has all of the frequency charts.
  • Joe TJoe T Junior Member Posts: 10
    Ishlachi wrote: »
    Has anyone seen a list of frequencies out there for the new ATSC channels? Also, any recommendations on a spectrum meter to measure both NTSC and ATSC channels?

    Thanks

    To see a list of channels specific to a reception area, try www.antennaweb.org
    The compass headings are a great install tool. As for a signal meter, the shop
    I work for has not upgraded yet. But all the digital stations went up on the same
    towers as the analog. So i guess I'm good till Febuary.

    Joe
  • viningvining X Member Posts: 4,364
    Is this for personal use or for customers? OTA ATSC is a real pain in the a$$ and not something that most folks will want to get invloved in unless all desired channels are in the same direction, distance and operating at nearly the same transmision power. Otherwise you have to use a rotor to optimize your reception and that may be to increase or decrease antennae gain while trying to amplify enough to pull in the weaker channels. I don't remember the thresholds but it used to be around -15dbmv to -25dbmv coming into the STB would allow you to view the station. Anything above or below that and you get nothing where as NTSC if you got signal you got a picture of varying qaulity, with ATSC if your signal is too good you get nothing and if your signal is too weak you get nothing. I haven't played with this for a few years now so maybe the STB threshold range is wider now but I'm sure it still isn't worth the aggravation of installing in a customers home, heck I wish I didn't do it in mine. The novelty wears off fast. Not to mention the tens of thousands who will be with out a viable OTA TV service. Oh, they'll get their free STB and maybe a channel or two but not nearly as many as with NTSC. Not to mention the ATSC tuner that was mandated to be installed in all TV sets of which 5-10 % will ever get used as long as most folks use cable or satellite.
  • TurnipTruckTurnipTruck Junior Member Posts: 1,485
    Most OTA ATSC tuners will deal with -15 to +15 dBmV. I have found them to more resistant adjacent channel and multipath issues than analog tuners were. Too strong is easily solve with an attenuator. You have to be careful with broadband amplifiers trying to amplify a weak signal though. If there is also a strong signal being amplified, you can create substantial intemodulation distortion, pretty much rendering all signals useless.

    I have designed quite a few OTA tuners few into my systems. There are often channels available from the air that you can't get from the local cable carrier, including weather and all-news channels. In most rural and suburban areas, the major stations all come from one direction. Usually the HD picture quality is better off-air than from cable or satellite due to one less person running the signal through their squeezebox.

    In my own system, I do have several different antennas. An antenna selector is automatically changed by my control system depending on what channel I'm tuned to. I watch as much as I can from the antennas versus the cable. I find it more personally satisfying.
  • viningvining X Member Posts: 4,364
    I guess if everything came from one direction that would simplify things but here in the North East (CT) I have signals coming from 5 different directions all at different distances and subsequently different signal strenghts. I have a multi antennae rooftop as well and one by Blonder Tongue made specifically for channel 10. It's a balancing act trying to amplify for the weakest staton w/o overdriving the stongest stations. I would usually have aim the antennae away form the broadcast direction to reduce the antennae gain for the stronger stations to compensate for the amplocation put in for the weaker stations. If there was external switcher available that would allow you to configure and then select amplification or antenuation paths for each station it would be a simple process but until some one makes such a device I'll stick w/ satellite or cable.
  • TurnipTruckTurnipTruck Junior Member Posts: 1,485
    Take a look at a parabolic antenna from Wade Antenna.

    True parabolics offer the best supression of off-axis signals. Long corner yagis are terrible for digital as their pattern varies tremendously with frequency. Given that a digital carrier is almost 6 MHz wide, it's often impossible to fight off the entire bandwidth of an interfering signal by means of antenna rotation.

    When you say you have a tuned Blonder-Tongue, I assume it's one of their BTY yagis. If so, look into making a horizontal array of two of them. In the Blonder Tongue Broadband Reference Guide are the formulas for nulling out signals from other directions by calculated horizontal spacing.
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