Obtaining Coverage Contours Data

Discussion in 'RabbitEars.Info Site Support' started by AndrewKao, Jun 25, 2019.

  1. AndrewKao

    AndrewKao Topic Starter New Member

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    Hey everyone, I'm completely new to the community, so sorry if this is extremely obvious.

    I'm working on a data intensive project for my thesis, where I would need to get the coverage boundaries for various DTV stations. I saw that rabbitears has data on coverage contour, such as that displayed here, and was wondering how I could replicate it.
    I've found that the FCC has hosted some data here ('TV Service Contour Data Points'), but they claim that this isn't precisely the same as the DTV allocations data — can anyone speak to how different they would be (and what the difference in terminology means here)?
    I've read that the FCC has a way of computing what the coverage boundaries are, but haven't been able to find a concrete reference — if there's a formula or document that lays out this stuff, that would help too!

    Also, let me know if this isn't the best place to post this question. Thanks so much!
     
  2. harshness

    harshness SatelliteGuys Master

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    Your timing isn't auspicious as many areas are involved in transitions due to the repack.

    I'm wondering if even those stations that aren't moving may have to make minor adjustments to their power level or coverage geometry to accommodate stations moving to their frequency.

    Trip should be able to explain what's going on with the data.
     
  3. primestar31

    primestar31 SatelliteGuys Master

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    Harsh, my area (Flint-Saginaw-Bay City) DMA just "finished" their move. Except for WAQP having a faulty repack antenna for RF36, so they are running at much lower power for now, all 3 of my other channels that moved are coming in almost exactly at the same apparent SNR levels as before.

    In fact, WBSF actually moved their antenna South 20 miles to their sister station WEYI, and claim (on a STA to upgrade the new transmission line) to be running at only 1/2 power as normal before move, YET they are coming in at a much improved SNR level as before. Actually, MUCH better from what I can see, and equal to WNEM before their repack, and WNEM has always been a blow-torch to me.

    So, this repack was a great success for ME anyway. I can only see it even better once WBSF & WAQP finish their bit of tweaking due to their new STA's.

    Anyway, I think the ultimate goal for moving stations at a minimum, is to at least maintain their DMA's balance and former signal levels, if not improve them a bit.
     
  4. harshness

    harshness SatelliteGuys Master

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    I'm looking at the repack from the perspective that it is far from over (even if your stations have moved) and until everyone gets settled, we won't know precisely how well the models represented the reality. Not everyone lives dozens of miles from any other markets but everyone is going to be swimming in a pool of frequencies that has been made much shallower without changing the modulation scheme. DTV has a less than stellar reputation for its performance in the lower frequencies and one of the big factors is multipath that may be a bigger issue when there are other distant stations booming their signals on the same frequency.

    Getting out better is a two edge sword if you're forced to protect another station.
     
  5. AndrewKao

    AndrewKao Topic Starter New Member

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    Thanks for the tip! I'm more interested in historical data (and it looks like anything before March 30 should be solid from here)—any idea if people have kept a dataset from before then?
     
  6. harshness

    harshness SatelliteGuys Master

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    Just so you know, the repack started testing in September 2018 and the first phase completed just after Thanksgiving.

    Trip is still your best shot for authoritative answers and I'm a little surprised he hasn't chimed in yet.
     
  7. Trip

    Trip RabbitEars Webmaster Staff Member HERE TO HELP YOU!

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    Good morning,

    Sorry for the late reply. How big a lift it is depends on what you're looking for. As you may know, TV is in the middle of a "repacking" process since Congress required the FCC to sell off part of the TV spectrum and move the remaining TV stations around to fit in what's left. If you want a copy of the contours from before the repack happened, from late 2015, you can find the appropriate ShapeFiles here: http://data.fcc.gov/download/incentive-auctions/OET-69/2015Nov_Sample_TVStudy_Results.zip Specifically, the contours ShapeFile. You can use the Sources ShapeFile to properly associate the contours with the individual stations.

    If you're looking for something more recent, your best bet for fully-FCC compliant contours would likely be to use the TVStudy software to generate new contours with the exact set of stations you want. If the exact protected contours aren't strictly necessary for your research, and ballpark ones will be okay, you could probably get away with the FCC-hosted dataset you link, though I've not actually looked at that data in a number of years and can't speak to its accuracy or how up to date it is.

    Feel free to reach out to me by private message if you wish.

    - Trip
     
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  8. AndrewKao

    AndrewKao Topic Starter New Member

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    The 2015 FCC shapefile is exactly what I was looking for, thanks so much Trip!

    The data looks nice and clean, but I may be back if there's some domain-specific knowledge that I'm ignorant of.
     
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  9. Trip

    Trip RabbitEars Webmaster Staff Member HERE TO HELP YOU!

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    Glad to hear it. Let me know if you need anything.

    - Trip
     

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