GOES 16 GRB downlink vs GVAR

Discussion in 'Free To Air (FTA) Discussion' started by GOES 12 GVAR user, Sep 17, 2017.

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  1. GOES 12 GVAR user

    GOES 12 GVAR user Topic Starter SatelliteGuys Pro

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    GOES instruments are designed to sense things just like those in Oklahoma. That's one of the missions of GOES.
    There are specific divisions of NOAA that do monitor the fire conditions. It was one reason that the satellite is designed the way it is.

    A link to other products the GOES can produce.
     
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  2. KWX

    KWX SatelliteGuys Family

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    That's some great news!!!
     
  3. KWX

    KWX SatelliteGuys Family

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    Hopefully I'll get some additional time this week to work some more on the LINUX app that I used to get the signal status and add streaming capabilities to send BB Frames to CSPP. Likely ensuring the BBF are synced before re-transmission will be the challenge for me. lol
     
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  4. N6BY

    N6BY Geek
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    weather01089 received a reply from Digital Devices last week. They told us that the DD card switches AGC (automatic gain) modes after a cable pull.

    There are 2 gain modes, NF and IIP3. After pulling the cable and reconnecting, the card goes into NF mode which is when streaming starts.

    They added a Windows registry key which is supposed to allow us to force the card into NF mode. But weather01089 tried it and it didn't help.

    My best guess is that streamreader.dll is somehow overriding the Windows registry setting. CrazyCat (author of streamreader) claims it doesn't, but I have doubts. So I am currently in the process of writing my own code to eliminate the need for streamreader.
     
  5. GOES 12 GVAR user

    GOES 12 GVAR user Topic Starter SatelliteGuys Pro

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    Question,
    Any recommendations for stream recording software?
    TBS recorder/IP tool don't work with the omnicom card. Got the driver installed but have no type of software to analyze it with, need some ideas.
    Has to work on Win XP.
    Otherwise have to go to option 2...
     
  6. N6BY

    N6BY Geek
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    EBS Pro can record from most DVB cards (and it is currently 'freeware'). Since it uses streamreader.dll you need to edit the streamreader.ini file and uncomment the line "NoPidFilter=1". Another possibility is TSReader, but the free version doesn't allow recording.

    And there are other programs you might want to try, like 'ProgDVB', 'SmartDVB' and 'DVB Dream'.

    Anyway, if you can get a recording from the card I can analyze it and see if it looks like it has valid BB Frames.
     
  7. GOES 12 GVAR user

    GOES 12 GVAR user Topic Starter SatelliteGuys Pro

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    Thanks again Brett,
    I installed EBS pro, installed fine.
    Got it set up and now I need to set up again and see what I've got.
    EBS Pro directly supports the omnicom card so I should have the best results I can get with it.
    I assume that when it records, it records it as it sees it. As I don't see a method of selecting TS or GS as in the TBS software.
     
  8. N6BY

    N6BY Geek
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    That is a good question. I don't know what will happen with the Omicom card. My TBS6983 card with GRBStreamer automatically selects TS or GS depending on the MAType-1 byte (the first byte of the BB Header). The Digital Devices Cine V7A also looks at the MAType-1 byte, but if it detects BB Frames it encloses them in a series of 188 byte TS packets.

    But I have never tried an Omicom card. Be sure to uncomment the line "NoPidFilter=1" in the streamreader.ini file. And then reboot your system to ensure that the change takes effect.

    If EBSPro gets confused by the GS stream then let me know and I will send you a version of GRBStreamer that records to a file.
     
  9. Micanopy Mike

    Micanopy Mike Active SatelliteGuys Member

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    I have been following the GOES GRB thread with great interest as I am interested in downlinking and displaying the near real-time animated GRB imagery. I noted the comment about being interested in downlinking the GOES West GVAR imagery. I happen to
    have a GVAR modem and a companion bit-stream synchronizer that was used for downlinking GOES-East GVAR a few years ago.
    I am guessing that they are suitable for the current GOES-West GVAR signal. Both of these items and their manuals are available
    if there is any interest in them. They have been sitting on a shelf in my workshop building for some years but were both functional when they were taken out of service. I am located in Micanopy, FL just 8 miles south of Gainesville, FL.

    As a side note, I am a rank-newbie at using forums like this one and totally unfamiliar with how to make them work. It took me a while to find out where to click to post a response to this long-running GRB / GVAR thread. I am currently working on RX and display of the GOES-East EMWIN imagery and have what I think is a pretty good signal level from my dish. The GRB signal also looks pretty strong as well but this photo is from a linear polarity feed and the CP GRB signal is reduced by several dB. I am not sure if it is good enough to actually use at this low signal level. I'll try to post a photo from my spectrum analyzer of the signals but am not sure how to do that. I see a place to click on to "Upload a File". Is this where/how I post a photo to this thread? What are the file size requirements for posting my .jpg photos? I will take a chance and try to post something that is pretty low-res. The LHCP feed is a homebrew version. I used a CP patch feed and attached a 0.4 dB NF / 20 dB gain LNA followed by a 2 dB NF / 30 dB gain amp to send the signal thru the 100-ft of 1/2" Andrews Heliax hardline coax into my workshop. The GOES signal photo is from a Tektronix spectrum analyzer inside my shop building. I hope these photos are a suitable file size for uploading onto this forum!
     

    Attached Files:

    #469 Micanopy Mike, Apr 18, 2018
    Last edited by a moderator: Apr 18, 2018
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  10. N6BY

    N6BY Geek
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    Welcome to the discussion.

    The GRB signal looks good as displayed in your photo. But unfortunately NOAA decided to include both polarities (LHCP and RHCP) at the same frequency. So with your linear polarity feed you're getting a mixture of both signals, and it would be impossible to process. A RHCP or LHCP circular polarity feed with good cross-polarity isolation is required for receiving GRB

    The information content is different on the two polarities. A list of the contents of each polarity is below. It's from the GOES GRB Product Users Guide.

    allocation.png
     
  11. GOES 12 GVAR user

    GOES 12 GVAR user Topic Starter SatelliteGuys Pro

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    Hi Micanopy Mike,
    Welcome.
    I don't need that hardware as I have a GVAR station here now. I am currently using GOES West.
    That hardware should be fine for GOES West but that satellite will be replaced by the end of the year with the "S" satellite or know known as GOES 17.
    GVAR is on the way out so that's why were here discussing this. GRB unlike GVAR uses DVB-S2 format instead of the BPSK stream.
    The nice thing about the new format is that the hardware is much more available to the user then when it was GVAR. However.. due the the bandwidth constraints NOAA packed all they could into 12 Mhz using both polarization's. This has caused a real headache for us as it requires some skill to get both streams.
    Along with what N6BY posted above it also takes an 8' dish on the east coast Min 10' if you want both streams for GRB, a waveguide feed of the septum type or the cantenna type.
    Again the feed must be circular polarized.
    A patch antenna may not work for this as it don't have the best match for a dish. You can try it, let us know.
    In my case I am only after the one stream so the setup is not as complex as the latter.
    Anyway, I will be here more over the weekend and hopefully have another dump ready. Have had little time and the weather has been relentless here.

    Also another little update, so far Novra seems to be very interested and is looking good. It got even better as CSPP Geo wanted to get in touch with them and coordinate their software with Novra's receiver.

    Also I will send you the Code for that display program I talked about Brett, see if you want to even look at it.
     
  12. Micanopy Mike

    Micanopy Mike Active SatelliteGuys Member

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    Hello, N6BY--

    It is Brett, isn't it? I think that is what I saw on the FCC license listing. I have been
    WA4HFR since around 1963. Some background on me; I built a GOES-East GVAR
    station for the U of Fl Climatology Research Department in 1981. The Climatology
    Department had a NASA contract to improve the freeze forecasting algorithms
    for the cold-sensitive agricultural interests of the state of Florida. Back then
    GOES products and imagery were not available on the Internet and the only way
    to acquire them in real time required a direct down-link.

    There was a huge clamor by local hams to receive the animated CONUS and
    Florida image sector. I (illegally) installed a 70-ft tower on top of my 4-floor office
    building and put an 18-ft tall stacked co-linear 13 dB gain omni-directional
    Super Stationmaster antenna on the tower. My office was on the 4th floor
    directly under the tower and I ran a 100-ft length of 1-inch Andrews Heliax
    hard-line coax down from the antenna and connected it to an amp from a
    defunct low-power TV station. The amp used a single Eimac 8877 (3CX1500)
    tube running full-legal power NTSC video on the ham 426.25 70cm band.
    With NTSC video, maximum average power applied to the antenna system
    is 57% of the peak sync tip power, even in a black scene. In normal program
    content this ratio may be around 25% or less. The nature of the GOES GVAR
    imagery was such that with such an effective antenna system the TX met
    all power restrictions.

    Clear video was easily received out to around a 25-28 mile radius from my
    office. This system ran 24/7/365 as a "beacon" for almost 10 years. Eventually,
    the GOES imagery became available on the Internet and the transmitter
    system was shut down.

    The RX consisted of an 16-ft dish feeding a de-mod box and a bit-stream
    synchronizer followed by some TTL hardware to decode the incoming data
    and then into an Amiga 2000 desktop computer to turn the data into
    image pixels and scan lines and then convert this into NTSC video.

    I had some experience with video as I had been chief-engineer for the
    U of F TV station WUFT-TV5 for several years. Interestingly, here in Florida
    hams use the 70 cm band on a secondary basis with the military as there
    is a bombing range not far from us near the Ocala National Forest and
    hams are limited to 50 watts TX power. A friend of mine was in charge
    of communications for the military in this region and I appealed to him
    for a power waiver. After about a month I received a document permitting
    me to run full legal power if I changed my originally selected frequency to
    426.25 MHz as the military was not using anything close to that exact
    frequency. I framed that letter and hung it on the rack holding the TX.
    The Eimac 8877 tube was capable of loafing along running 1500 watts
    peak video sync-tip power. The 8877 tubes were expensive and started to
    get soft after around 8K or 9K hours. Every year or so the 40 or 50 area hams
    watching the GOES GVAR video took up a collection for a new tube.

    Eventually, the GOES GVAR downlink was shut down when the NASA
    development contract ended and the GVAR system was declared
    surplus, dismantled and declared available for salvage. Unfortunately,
    the dish was acquired by another U of F department. I saved the
    GVAR modem and bit-sync and took my tower and antenna home.
    It was a fun side-line project while it lasted!
    **************
    My current interests are: A) Downlinking the new GOES-East EMWIN
    signal and eventually; B) Downlinking the GOES East GRB signal. I am
    primarily interested in the animated Geo-Color imagery. However,
    it is not clear to me if this product is contained in just one circular
    polarity signal or if it requires processing both circular polarity
    signals to produce. Any info on this will be much appreciated!!
    *************

    One last item: You said--
    > A patch antenna may not work for this as it don't have the best match
    for a dish. You can try it, let us know.
    *******

    Hmmmm.... CP Patch feeds are commonly used on commercial
    V-sat off-set (and some prime-focus) dishes. I do get more GRB
    signal with the CP patch than with the linear polarity feed but I will
    have to take another look at it and let you know what I see.
    *********

    Yikes-- I see that I have gotten carried away with far too long of a
    text post. I tend to do that... My apologies!

    Mike Baker
    *********
     
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  13. N6BY

    N6BY Geek
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    Yes, Brett in California here. I was in first grade when you got your license. :) I got my ham license in 1998 and let it expire. Then I got back into the hobby in '14. This time I won't let it expire because it was difficult to get the 4 character call. When it became available myself and 10 other people applied for it. Luckily I won the FCC's random selection. So I plan to retain it for the rest of my life!
    Broadcasting live weather images for a 25 mile radius sounds like a fascinating project! It would have been really nice if they had let you keep that 16 foot dish.
    For A) As you probably already know, EMWIN was merged with HRIT and is being sent at 1694.1 MHz with BPSK modulation. Here is a link to an overview of it: http://satelliteconferences.noaa.gov/2015/doc/NSC2015Posters/1_6.pdf The Open Satellite Group has developed a suite of programs for use with an SDR to demodulate the BPSK and process the images. The GitHub for it is here: Open Satellite Project And the chat group is at: OpenSatelliteProject I hope to see you there.

    For B) To answer your question, unfortunately you need to receive both polarities to get all the spectral bands necessary to simulate natural color. You need channel 2 from the LHCP signal. The rest is on RHCP. (My post #470 shows what is on each polarity). In the chat group Ray (weather01089) has posted several natural color images that he received using a septum feed connected to a Digital Devices V7A DVB receiver. On one Windows computer he runs my program named 'GRBStreamer' to read the incoming data from the DVB receiver and send it via UDP to a Linux computer running CSPP-Geo software. He has developed scripts to merge the channels into natural color. The Digital Devices receiver has two tuner inputs, so he can stream and process both RHCP and LHCP at the same time. To do that he runs two instances of GRBStreamer, one for RHCP and one for LHCP. Both my program and CSPP-Geo are free. An alternative to CSPP-Geo is 'GRBDump', which was written by the founder of the Open Satellite Group. But it is not fast enough to keep up with the stream and he hasn't issued any updates for several months.

    The main issue we are trying to tackle now is that in order for the DVB card to start sending data to my program, it requires disconnecting and reconnecting the coax inputs! Very strange. We think it has to do with the gain mode in the DVB receiver. When you pull the cable and reconnect it switches gain modes and starts working.

    I have spent the last several days writing some program code to access the DVB card at a level closer to the hardware. Currently my program uses a third-party library 'streamreader.dll' which has high level (easy to use) access to DVB receivers. But it is closed source and does not allow the kind of access I need. So I am writing code to replace streamreader and give me low-level access to the receiver.
    GOES 12 GVAR USER said that. I haven't tried a patch feed for GRB yet, but I did get good results with a patch feed to receive another L-Band signal called 'Outernet'. It's in the 4th photo of my first post here: Experimenting with L-Band antennas

    But Outernet was sending only one polarity on the frequency. I am not sure how well patch feeds do with cross-polarity isolation as required for GRB.

    Anyway, we have made a lot of progress over the past several months with receiving and processing GRB at a minimum cost!
     
    #473 N6BY, Apr 21, 2018
    Last edited: Apr 21, 2018
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  14. GOES 12 GVAR user

    GOES 12 GVAR user Topic Starter SatelliteGuys Pro

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    You know Mike brings up a good point.
    There is little info on how to use this forum. So I will make a quick guide on here for everybody.
    As you have already found out the reply box is at the end of the forum.
    Or you can click the reply button below the post as well.
    Post page.JPG
    Below that reply box is the (post reply box) and (upload a file box)

    The (post reply box) posts what you write in the reply box.
    Post reply box.JPG
    The (upload a file box) uploads images or code. The size will be scaled if it's too big to post. I find anything of a 150 Kb is fine to post for an image.
    Upload a file box.JPG
    After you upload the image you get a choice to insert a thumbnail or the full image. You used the the thumbnail option above. If uploading several images you can choose to upload them all as thumbnails or full images.
    Upload a file options.JPG
    The image is placed where the cursor is located on the page.
    Upload image location.JPG

    The last thing we use a lot here is the "quote"
    To quote what someone said you must highlight it first then click quote button to
    quote it.
    quote option.JPG
    To post the quote you must put the cursor where you want the quote to start and click the (insert quote box) below.
    insert quote box.JPG
    You will get a review selected message popup box
    Review selected message box.JPG
    click (quote these messages)
    done..
    Done.JPG

    Pages buttons:
    pages buttons.JPG
    The current page you are on is highlighted, you can click on any of the other pages to go to that page.

    Lastly is the like button.
    Like button.JPG
    If you like what you read then you can click the like button to "like it" we like that.

    There you go, a basic crash course on how to use the forum.
     
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  15. GOES 12 GVAR user

    GOES 12 GVAR user Topic Starter SatelliteGuys Pro

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    Hi Mike,
    Tim here GOES 12 GVAR User
    Ya, GVAR stations at that time were very expensive. The single user would have put out quite a bit to set up one. Let alone the TV Xmitter to share the data.
    And so are GRB stations but we here are changing that so that cost is much more manageable. Also with the data age the cost of this stuff is coming down in a big way.
    Mike consider this a ragchew (non hams term "Discussion") on GOES GVAR and GRB, I have allowed some content of NOAAPORT and a little on EMWIN but we are keeping this on GRB and GVAR as there is a lot to take in with this for any new user.
    We have been exchanging ideas and designs, theory and facts. Trying to see what works and don't.
    Before there wasn't too much on GRB as the single user couldn't afford to setup such an advanced earth station. But between several forums, discussions and trial and error we have made it possible to set one up.
    Since you have received GVAR you will be familiar with the basics and dish antennas. That's a big start.
    Besides the format change for GVAR to GRB so has the data rate. From 2.11 Mbps to 32 Mbps. This is important as the computer processing this will have to be able to handle it.
    What the focus for me has been here so far is receiving the data streams and making NetCDF files, as that is what is sent from the spacecraft.
    These files are the full resolution of the ABI and the files are large. As were channel 1 of the GVAR imager. There are 3 on the ABI and that's just scratching the surface.
    As with anybody coming on here I recommend that you read through the forum first as there are now 24 pages/ 473 posts to it and I have to go back every so often to research what was said.
    Mike, in the first page of the forum there's the GOES R Pug. It's a manual of the GOES R GRB downlink. Found in post #2 of the forum.
    In there you you find all the details about the GRB downlink, since you have expertise in this you should be able to follow what NOAA talks about in there and the details.
    Brett covers the HRIT well. I may at some time start a post on HRIT as there are many things the have come along there.
    The reason I mentioned the patch antenna is: The research I have done states that a patch antenna will under or not evenly illuminate a dish therefore resulting in and less then ideal antenna performance.
    It was proven by W1GHZ that the waveguide feed was indeed the best to be used with dishes at or greater the 20 wavelengths in dia. Those guys at 1.2 Ghz have made many feeds and setups to make the most of what they use.
    There were several cases that they ran simulations and did the actual test to confirm the results.
    A patch antenna may work with an offset dish but I can't confirm that.
    But if you have it try it. It will need to be circular polarized to work. I posted in the forum how to make a wavegide dual probe feed to receive 1 of the streams.
    KWX currently uses that feed.
    As Brett also stated you will need both streams to get the RGB visible image. The RGB image is made by combining the red channel, blue channel and the green channel together. As I stated above the RGB image is 3 visible images combined. This is a very large image when done. But it does look great.
    You will be looking at a Min 10' dish to get both streams there in Fl. And the bigger the dish the more margin you will have. If you could get both on an 8' dish you won't have much margin. Unlike GVAR that if you get errors in the bits the image will get speckles in it.
    In GRB if you lose the sync to the signal you lose that image as the receiver disregards any data after loss. This is all due to how the data is sent via DVB-S2. So signal margin is critical even though there is error correction designed into the streams.
    Don't feel that you're getting carried away, this is a discussion. :)
     
  16. GOES 12 GVAR user

    GOES 12 GVAR user Topic Starter SatelliteGuys Pro

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    Brett, Got another dump for you.
    Link to dump
    Recordings are 15, 20, 25 Sec. long
    Almost had a disaster, The first time I set up I got nothing... flat line. Couldn't for the life of me figure out why.
    After tearing down the desktop computer I had set up I thought I would try with the Novra 300D receiver.
    It was a good thing as I learned the the center pin of the coax got pushed out of the F connector on my adapter.
    So after fixing that and confirming that I had the signal on the 300D, I reluctantly went back to the desktop computer with the Omicom card. Success, The card locked and outputted the TS. Showed all info of the signal and the dumps look far better then with the TBS receiver.
    The only complaint I have is the signal level wasn't as strong as I thought it should be.
    I could lock either way, L/R polarization's.
    These images show the locked signal on both polarization's. In the background you see a spectrum scan that I did.
    locked 1.JPG
    locked 2.JPG

    The next 2 images show the TS output.
    output 1.JPG
    output 2.JPG
     
  17. N6BY

    N6BY Geek
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    I checked all the files with a program called 'BBAnalyzer' which was written by a guy on Ricks forum. Unfortunately, it only found a few valid BBHeaders in each of the 15, 20 and 25 second files.

    Looking closer with my hex editor, I found a 'fill frame' which contains the text "PACKET USED TO FILL TRANSFER FRAMES" repeated over and over. Looks like approx. 1 out of every 20 bytes are wrong in the 25 second recording. I have attached a screen shot where you can see this. One of the lines starts with 'PACKET WSED' (W instead of U).

    So it looks like the error rate is way too high to process.

    I would suggest moving your dish to 89.5W where GOES-17 has recently started testing the GRB signal. Hopefully you will get a good signal from that.
    Dump25.png
     
  18. GOES 12 GVAR user

    GOES 12 GVAR user Topic Starter SatelliteGuys Pro

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    Ouch, this don't look too good for me. :oldno
    Hard to believe that a 10' dish is inadequate for this here.
    Well, on the bright side we may have another option for hardware.
    I can get no more out of what I have here. By the end of the year the 12' dish will be available but not until then.
    Thanks again.
     
  19. KWX

    KWX SatelliteGuys Family

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    Darn, only 6.2. See if you can still get it a bit past at or past 6.5 as it will at least allow you to get something specially during good weather and to test your equipment while you wait to get the 12ft later this year.
    LOL you almost scared me with "Almost had a disaster..." part. In regards the locking and streaming capabilities of the OMICON, did you had to reset the coax any number of times in order to get it to start streaming?
    Finally, check out GOES17 as Brett mentioned.
     
  20. GOES 12 GVAR user

    GOES 12 GVAR user Topic Starter SatelliteGuys Pro

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    KWX ,do you have a public email you don't mind to share,
    or a temporary one I can contact you on?

    No, It locked several times in the signal analyzer program without me doing anything but entering the proper info and to click the lock button.
     
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