Interactive Beam Footprint Library

Discussion in 'DIRECTV Tips and Resources' started by Gary Toma, Jun 17, 2011.

  1. cpalmer2k

    cpalmer2k New Member

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    Can someone help me locate which "Beam" map above covers my locals? I'm probably just missing it, but I haven't been able to figure it out.

    I'm in the Greenville, SC DMA. Our locals come from D12@103W. I see the maps for every other DMA around me, but unless I'm just missing it can't find mine.
     
  2. HoTat2

    HoTat2 Hall Of Fame

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    Tom's TPN data for D12 published back on 7/8/15 list the Knoxville, TN. spotbeam A2B4 as serving the Greenville, SC DMA.

    Sent from my SGH-M819N using Tapatalk
     
  3. cpalmer2k

    cpalmer2k New Member

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    Thank you! I'd looked at all the spot beams for SC, NC, and GA, but never thought of Knoxville being the one that carried us. The map is intriguing too. My locals are my official ones, yet my area lies well outside of the "white" ring and much closer to the blue ring on the map. In fact two entire counties of the DMA are outside of the white rings. I guess that explains the lower transponder readings (and worse rain fade on my locals).
     
  4. tomspeer46

    tomspeer46 Legend

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    I have found that, in general, DirecTV considers anything inside the blue ring as adequate signal strength, and in some cases (like mine, In the NE corner of the Albany, NY DMA) the boundary between where they will install HD vs SD only is somewhere between the blue and green rings. I am just outside the blue contour (as presented in the Beam Footprint library) and have HD service, with no clear line of sight to the SD locals on 119. I get a 90 signal reading on a spot beam centered about 200 miles east.

    The names in the Beam Footprint Library are somewhat misleading. Someone took a look at the footprint of the beam and named them for what they saw.
    In the case of the D12 A3B1 beam which serves Hartford, CT, and Albany, NY DMAs, primarily, The area inside the blue contour, includes all of New Hampshire, Massachusetts (except Nantucket), Rhode Island, Connecticut, and parts of New York, Vermont, New Jersey and Maine. They called it "Boston", yet it could not serve the Boston DMA because it doesn't include Nantucket Island.
     
  5. Nov 7, 2015 #145 of 194
    cpalmer2k

    cpalmer2k New Member

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    I have one more question for you.. would you consider a transponder reading of "66" to be a usable signal, or is that way too low? As mentioned my locals (yes, my official ones) are on a very distant spot beam, and some come from different transponders (PBS's that also serve other markets). The highest signal I get on any of my locals transponders is 88, with 66 on the low end channels. It isn't an alignment issue because neighboring DMA's transponders come in at a 99 and 98 off the same satellite.
     
  6. Nov 7, 2015 #146 of 194
    inkahauts

    inkahauts Well-Known Member

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    What are your signals on 99 ca and 99 CB and 103 ca and 103 CB. That will tell you if you have an alignment issue. Spots really won't be as good as an indicator of you are in a fringe area.

    66 is quite low but useable. As long as you don't have a lot of weather. Then it'll likely go out quickly. I'd be curious if your SD locas have higher signals. You can switch to them if you start losing signal on the Hi Definition feeds.
     
  7. Gary Toma

    Gary Toma UNIX

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    Thanks to a tremendous amount of time, research and dedication by Tom Speer, we now have a library entry showing all the spot beam footprints provided by D11. Only 3 official beam footprints were submitted to the FCC at the time of D11's filing. These new D11 beams are a calculated deviation from their counterpart antenna on D12.

    Doctor J researched the D11 to D12 beam correlations and published a definitive document on that topic here at dbstalk in August, 2011.

    Working through this process for D11, Tom has come up with some standard ways of naming the beams to make them more meaningful and easier to work with. That advanced naming technique is seen in these brand new D11 beams. As Tom works through the existing beam footprint listings for other satellites, these naming conventions will also be applied.

    One additional feature provided in the D11 Beam Footprint Library is the inclusion of a 'Group-Display' for each antenna, or reflector. This one map shows all the Beams provided by that given antenna. We hope in time to provide this 'Group-Display' capability for each antenna of all the other satellites.
     
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  8. slice1900

    slice1900 Well-Known Member

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    Wow, that's really cool, thanks for all the hard work!

    One request, when you rename the spot beams on D12 and D14, can you preserve the "official" names from the FCC documents in parenthesis or something? Just so if we look up information in the FCC documents it is easy to link them to the correct beam? Sometimes the city names Directv used aren't clear on details like which Charleston they are for, or what the heck Presque Isle is, so if it is changed to a geographic reference in those cases it'll be harder to make the association without the cheat sheet included :)
     
  9. HoTat2

    HoTat2 Hall Of Fame

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    +1 as well ...

    Thanks for all the hard work ...

    I was wondering what the links for the 4 spotbeam transmit antennas was about since those are emanating an entire bouquet of beams.

    And good luck to Tom going foward with trying to do this with the spotbeam antennas for the Ku band birds D7S and D9S. While I've found one document indentifying which of their three spotbeam antennas, "NW," "SW," and "SE," receive each uplink station when in the 119 configuration (D7S at present). What downlink spotbeams are assigned to which of those three spot antennas is not given.

    It can be "assumed" that except for the nationals the same spotbeam antenna serving the uplink also transmits the local downlinks that station provides. But that's just speculation.

    Sent from my SGH-M819N using Tapatalk
     
  10. tomspeer46

    tomspeer46 Legend

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    What "official" names are you talking about? The only names for the downlink spotbeams that I find in any of the D12 (or D10) filings are the Antenna/Beam designators such as A1B1 for Antenna 1 Beam 1 or A4BB for Antenna 4 Beam 11. I am working on D12 now. Your comment made me go back to the Schedule S databases and documents I downloaded from the FCC filings for D12. I find no DMA or city names associated with the downlink beams. I am willing to consider your request, if you can point me to the FCC documents you are referring to.
     
  11. tomspeer46

    tomspeer46 Legend

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    The Antenna Group kmz files include all of the information for all of the beams that emanate from that antenna. The viewpoint is from the satellite, but at lower than orbital elevation to zoom in. Notice that all of the beams are nearly circular from this viewpoint, They are circular when viewed from the satellite's position, but the Earth looks really smalll from 22,300 miles out.

    The only contour ring displayed for each beam is the 51.5 dBw ring, which is the level that DTV uses for most of the country on CONUS beams, and appears to be their minimum usable level for the edges of DMAs for spot beams. Using the "Places" section on the left of the Google Earth Screen, You can click on any beam name to zoom into that beam, You can click on the + sign to expand any container, and use the check boxes to display or hide the objects you want to see. If you uncheck the "Contours/Markers" container, then check it on again, all of the contours for that beam appear. I would recommend selectively turning on rings of interest. The rings outside of 48 dBW usually are not of interest, and just create clutter.

    You can load all 4 Antennas into Google Earth and see how the patterns blanket the country. You can use the check marks on the antenna container to display or not display any Antenna pattern.

    I developed these displays to aid in matching the beams to the DMAs they serve, comparing them to the Neilsen DMA map. The individual beams that Gary has posted were all extracted from the Antenna Group file. The derived D11 footprints are approximations, based on engineering judgement, given the limited information in the public domain.

    Since D12 was built as spare for both D10 and D11, we started this project assuming that we could come up with a constant offset from the D12 beam pattern to get D11's pattern. We calculated the offset using the three known beam patterns for D11 in the FCC filings, which are all on Antenna 1. That worked well for all of Antenna 1, the footprints matched the DMAs being served. When we applied the same offset to Antenna 2, they didn't line up right. So, we have made the assumption that DirecTV can make minor adjustments to the reflectors (antennnas) from the ground. I figured out the incremental shifts from the offsets used for Antenna 1 needed to make the entire pattern of each Antenna align with the DMAs it serves. I supplied the offsets, Gary calculated the new footprints, I checked them. After several iterations, we declared it "the best we can do". If, in fact, DirecTV can adjust the position of the individual feed horns, feeding each reflector, then some of these beams could be better aligned with their DMAs. But then we would have no way of predicting the exact beam footprint. The footprints created by assuming only the reflector is adjustable work.
     
  12. slice1900

    slice1900 Well-Known Member

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    Sorry, I assumed that the beam names listed in the footprint maps were provided by Directv somewhere in the documents, but it sounds like that's not the case and Gary (or someone else at dbstalk) gave them a name based on the DMA they were being used for.
     
  13. tomspeer46

    tomspeer46 Legend

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    I don't know who assigned the names that have been used for the beams in the beam footprint library. From observation, it appears that they looked at the center of each beam, found the nearest city and called it that, quickly. That has created such badly named beams as D12's A3B1 which was called "Boston". It still is, when you load it into Google Earth, although Gary has renamed the file "Hartford_Albany" in the beam footprint library. It centers on the little community of New Boston, NH, and might better have been named "Keene" or "Manchester" for the two population centers on either side of it. Except it doesn't serve those cities. Beam A3B1 primarily serves the Albany-Schenectady-Troy and Hartford-New Haven DMAs. It does provide a signal off TID 150, VPID 1060, which is Connecticut Public Television to Hartford and at least part of the New York and Providence DMAs, while giving it different station call signs and channel numbers in their guide entries. The beam can provide service to all of Western NY and New England, but since its two TID's are pretty full up serving Albany and Hartford (the first city names in the DMA names), Hartford_Albany seems like a good name.

    In other cases, we find that one beam serves 5 or 6 DMAs, and the name would get too long. That is when I have chosen to name it based on it's geographic footprint. At least I try to follow those rules, there are a lot of beams.

    Gary and I are working to make the Satellite Transponder Map that I create, and the Beam Footprint Library, have a consistent name for the beam. I am choosing the beam names, with guidance from Gary about how he wants to standardize. So if you have any problem with them, I will consider complaints for a future revision.

    BTW, I live in the far northwest corner of the Albany DMA, just beyond the 55.5 dBw contour of A3B1, sometimes.
     
  14. slice1900

    slice1900 Well-Known Member

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    OK thanks...sounds like you two are well on top of this and I should have shut up and trust the experts to handle it :)
     
  15. HoTat2

    HoTat2 Hall Of Fame

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    You meant a "...lower than orbital 'altitude' to zoom in." here didn't you?



    Sent from my SGH-M819N using Tapatalk
     
  16. tomspeer46

    tomspeer46 Legend

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    Yes , in my mind, elevation and altitude are the same thing.
     
  17. tomspeer46

    tomspeer46 Legend

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    When aiming a receiver antenna, ""elevation" refers to the surveyors notion of the term, meaning an angle of elevation. I am a mountain hiker. I think of elevation in mapping as the height above sea level. Different perspectives.
     
  18. tomspeer46

    tomspeer46 Legend

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    Slice, I'm not trying to put you down. I appreciate your comments on many DirecTV subjects, especially the electronic related ones., There has been a great deal of back and forth between Gary and I outside of the forum on this project. Gary posted these beams, this week, before he heads off on some personal time. I have written my responses here so that you folks can understand our motivations, methods, and assumptions. I hope my explanation of the combined beam antenna files will help all of you use them as they were intended. I created them for the my use in the D11 footprint project and Gary thought we ought to publish them. Let me know if they are useful. From what I have learned over the past couple of weeks about manipulating Google Earth objects, I can produce more of them for other satellites. I welcome constructive criticism, and will be happy to answer any questions, either here or in PMs. I prefer to use this forum for things that will enlighten other members, and take detail criticism and questions as PM's.
     
  19. tomspeer46

    tomspeer46 Legend

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    One other thing. The D11 footprint calculation was Gary's project. The idea of calculating the D11 footprints was his, and he did all the hard work of calculating the new contours and getting them into beam footprint files. I was the quality control guy, checking the footprints with what we knew to be reality. My main job was supposed to be formulating names, but since I was already becoming adept at examining the beam footprints and comparing them to DMAs, I helped fine tune Gary's work while coming up with the D11 beam names. In creating techniques for analyzing the footprints I created the Antenna pattern files, which also became the containers for the new footprints on this project.

    Gary's first communication about this was exactly four weeks ago. The real work was accomplished in a span of two weeks. It has been intense, and we each have had to take time away for personal matters, but it gave us something to do while DirecTV is not changing much in the TPN maps.
     
  20. slice1900

    slice1900 Well-Known Member

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    So not to come up with more work for you guys, but one thing I've been wondering about is the zip code -> list of OTA channels mapping. From playing around with the AM21 adding secondary markets I've noticed that choosing different zips within a DMA gets you a different list of channels. That makes sense since an antenna on one edge versus the other edge of a DMA will be capable of receiving a different set of OTA stations, especially in the larger DMAs west of the Mississippi.

    The data we have in the TPN map just shows a single ZIP per DMA and a list of channels. I'm not sure if the data I'm talking about can be found within the guide data being used to generate that OTA spreadsheet, or if it is contained in a separate stream. I tend toward the latter - I think that is accessing that 'secondary' stream when you enter a ZIP code and it says "searching for local market".

    If you guys find anything that looks like that, feel free to contact me I'd be happy to play around with it and see if I can figure out its mysteries.
     

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