Up until several years ago I worked at a satellite ground station (government contractor). I retro-fitted some legacy L-band feeds with helix elements for S-band. The dishes were .4 f/D with 130 degree 10dB edge taper. So, my research and testing resulted in a helix of 2.125 turns for optimal beamwidth. Two jobs later (did instrumenting of gun test for the past 5 years), I'm back in RF work (thankfully, as I started to miss it after not doing it for a couple years) and used these specs to fit a L-band feed on a 6' dish for GOES and POES satellites. GOES were kind of weak on the spectrum, but the LEO POES birds were booming.
GOES 16 GRB downlink vs GVAR
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Up until several years ago I worked at a satellite ground station (government contractor). I retro-fitted some legacy L-band feeds with helix elements for S-band. The dishes were .4 f/D with 130 degree 10dB edge taper. So, my research and testing resulted in a helix of 2.125 turns for optimal beamwidth. Two jobs later (did instrumenting of gun test for the past 5 years), I'm back in RF work (thankfully, as I started to miss it after not doing it for a couple years) and used these specs to fit a L-band feed on a 6' dish for GOES and POES satellites. GOES were kind of weak on the spectrum, but the LEO POES birds were booming.
Hi. Is there any way to nest two helix's to recieve both RHCP and LHCP at the same time?
Hello, All--
I see no posts have been made for a long time on this GOES GRB forum.
What happened? Why did posting stop? I have a question.... My only
interest in the GRB signal is to obtain the false color GeoColor imagery.
In addition to the various infrared spectral imagery channels does the GRB
downlink signal also contain the false color GeoColor imagery?
If so, has anyone been successful at downlinking and displaying the
animated sequential GeoColor images? I am in N. Central Florida and
have a very strong GRB signal from my 12-ft dish. I have a CP septum
feed with a little over 22 dB of isolation between the LH and the RH polarity.
Are there any other forums that focus on downlinking and displaying
the GRB imagery and especially the GeoColor imagery? Thanks for any
feedback on this!!! My email is mpb45@clanbaker.org
Mike in Gainesville / Micanopy, Florida
*******************************
I see no posts have been made for a long time on this GOES GRB forum.
What happened? Why did posting stop? I have a question.... My only
interest in the GRB signal is to obtain the false color GeoColor imagery.
In addition to the various infrared spectral imagery channels does the GRB
downlink signal also contain the false color GeoColor imagery?
If so, has anyone been successful at downlinking and displaying the
animated sequential GeoColor images? I am in N. Central Florida and
have a very strong GRB signal from my 12-ft dish. I have a CP septum
feed with a little over 22 dB of isolation between the LH and the RH polarity.
Are there any other forums that focus on downlinking and displaying
the GRB imagery and especially the GeoColor imagery? Thanks for any
feedback on this!!! My email is mpb45@clanbaker.org
Mike in Gainesville / Micanopy, Florida
*******************************
I made a video of the transit of Mercury this morning, as seen by GOES-16. I used GRB Imager and my 10 foot satellite dish with a new can feed and combiner kindly provided by Ed Murashie. His GRB can feed hardware outperform my septum feed by about 2 dB! It's much lighter too.
In this video you can see Mercury as a tiny black dot moving from the lower left to the upper right of the sun. It's hard to see unless you view it in full screen mode.
There is an active chat group about GRB reception here: OpenSatelliteProject
In this video you can see Mercury as a tiny black dot moving from the lower left to the upper right of the sun. It's hard to see unless you view it in full screen mode.
There is an active chat group about GRB reception here: OpenSatelliteProject
There are currently 2 known ways to receive GRB:
1) Buy a very expensive $20,000 rack mount GRB receiver/demodulator
2) Install a TBS6903 or Digital Devices DVB Cine S2 V7A DVB card in a Windows PC and use my GRB Streamer or GRB Imager programs. If you use GRB Streamer you can stream to a Linux box running a major suite of very capable GRB programs developed by the University of Wisconsin.
I am currently helping another company develop a 3rd method -- a standalone box which will cost approx. $1K. They have it mostly working but it loses data periodically. I am trying to help them find the cause of the data loss.
1) Buy a very expensive $20,000 rack mount GRB receiver/demodulator
2) Install a TBS6903 or Digital Devices DVB Cine S2 V7A DVB card in a Windows PC and use my GRB Streamer or GRB Imager programs. If you use GRB Streamer you can stream to a Linux box running a major suite of very capable GRB programs developed by the University of Wisconsin.
I am currently helping another company develop a 3rd method -- a standalone box which will cost approx. $1K. They have it mostly working but it loses data periodically. I am trying to help them find the cause of the data loss.
After a lot of testing and troubleshooting, I think the standalone GRB receiver box is working now. It is getting fewer errors than my Digital Devices DVB Cine S2 V7A DVB card.
I wrote a diagnostic program that analyzes the stream output by the standalone box and makes an error log.
The company that's developing it does not have a 10 foot GRB dish, so they are relying on me and another guy to test it.
Anyway, it will be a great alternative to an existing GRB receiver box, which has a five figure price.
I wrote a diagnostic program that analyzes the stream output by the standalone box and makes an error log.
The company that's developing it does not have a 10 foot GRB dish, so they are relying on me and another guy to test it.
Anyway, it will be a great alternative to an existing GRB receiver box, which has a five figure price.
Well the GRB receiver box worked great for 18 hours. But then it started getting a flood of errors.
I sent copies of the logs I made and told the developer my thoughts on the cause and he agreed. Fortunately it is not a reception issue. Just a problem managing the data coming in and out.
I sent copies of the logs I made and told the developer my thoughts on the cause and he agreed. Fortunately it is not a reception issue. Just a problem managing the data coming in and out.
Long time here,
I have had no workings with GRB on direct reception since May 2019. All my previous pictures on here of my system in working order are no longer reflect that system.
In May the river behind my house flooded big time, I had to take all my systems down and pack them away. When I get to setting things back up at a new place I will have to go through the feed electronics and find out what is damaged and what made it.
The computers luckily were removed before the water came.
As I said in past posts about my system, it consisted of a feed, amp, coax using a USB power supply (see my posts on how I built my amp several pages back).
The computer ran GRB imager and saved the files as TIG files. I used another laptop computer running a simple slide show program batch file and networking to move the files from the GRB machine to the laptop display computer.
The last change I made to my GRB computer was to put a 1 TB solid state dive for storing the images in, it made accessing them much quicker.
I have had no workings with GRB on direct reception since May 2019. All my previous pictures on here of my system in working order are no longer reflect that system.
In May the river behind my house flooded big time, I had to take all my systems down and pack them away. When I get to setting things back up at a new place I will have to go through the feed electronics and find out what is damaged and what made it.
The computers luckily were removed before the water came.
As I said in past posts about my system, it consisted of a feed, amp, coax using a USB power supply (see my posts on how I built my amp several pages back).
The computer ran GRB imager and saved the files as TIG files. I used another laptop computer running a simple slide show program batch file and networking to move the files from the GRB machine to the laptop display computer.
The last change I made to my GRB computer was to put a 1 TB solid state dive for storing the images in, it made accessing them much quicker.
Sorry to hear about the flooding. Hope you can salvage all/most of your equipment.
They (Novra) got the GRB box working better. They fixed the problems I reported back in June.
Later I reported some bugs with Novra's GUI interface but have not heard back about any fixes for it.
The Novra box sent to the Department of Homeland security worked for a while and then could no maintain a signal lock. I think they went back to using a TBS DVB card on a Windows PC running my 'GRB Streamer' program while they are searching for a fix, possibly with the amplifiers.
I haven't been doing any further development of GRB Streamer (doesn't need it) or GRB Imager (could use it) because of injuries/illnesses I have had over the past 11 months. But I thought I would post here to help keep the thread from being closed due to lack of use.
Also, if anyone wants GRB Streamer or GRB Imager please let me know and I can direct you to the latest version (it's currently offered at no charge).
Today I participated in an online meeting of the NOAA GRB USERs group.
There was a presentation/20 minute advertisement by Novra about their new receiver.
There was also a presentation of what we have done here and on the chat group (developed a low cost GRB receiving station). There were no audience questions and I sensed a lack of interest.
The number of known hobbyists with their own GRB station is very low. I think that number is less than a dozen. Its not worth spending hundreds of hours improving software used by so few.
And I must admit, I rarely turn on my reciever. So unless something major happens, I think this GRB thing is a done deal.
There was a presentation/20 minute advertisement by Novra about their new receiver.
There was also a presentation of what we have done here and on the chat group (developed a low cost GRB receiving station). There were no audience questions and I sensed a lack of interest.
The number of known hobbyists with their own GRB station is very low. I think that number is less than a dozen. Its not worth spending hundreds of hours improving software used by so few.
And I must admit, I rarely turn on my reciever. So unless something major happens, I think this GRB thing is a done deal.
Hi everyone,
Due to some policy changes on Google sites I ended up removing the site GRB BBF for view site and some
other image loop links.
Posts affected #605 (Google Sites links are dead)
Post #607
Movie link is dead
Post #648
Links dead to image loop files
I still have these files and will share them if asked, I will just have to send them to you.
Due to some policy changes on Google sites I ended up removing the site GRB BBF for view site and some
other image loop links.
Posts affected #605 (Google Sites links are dead)
Post #607
Movie link is dead
Post #648
Links dead to image loop files
I still have these files and will share them if asked, I will just have to send them to you.
All I ask Brett is that you please do the updates so the software keeps working. As sometimes NOAA changes some of the specs. Though it a shame that things go that way.
So 8 months have elapsed since the previous post and unfortunately I have some news that is not good for GRB hobbyists.
1) Ed Murashie is no longer making his excellent GRB can feed with a custom designed splitter/combiner. It was far superior to the septum feed that I built. I think it died due to lack of interest. There are an extremely small number of people with the desire to build a GRB ground station. I only get about 1 or 2 requests per year from people wanting to buy a copy of my program - "GRB Imager".
2) The Digital Devices Cine S2 V7A is no longer being made. It worked well for GRB.
3) The TBS6903 is being replaced by the TBS6903X with a different chipset. This new card does not work with GRB, and it likely never will unless the demodulator chip manufacturer releases the detailed specifications and register information to the public.
There may be a small remaining stock of TBS6903's somewhere. But I just heard from a guy who ordered a TBS6903 direct from TBS and sent him a TBS6903X instead.
This all means that it may no longer be possible to obtain a new DVB-S2 card for GRB use. And you are left with the choice of either building your own septum feed or purchasing one from RF HamDesign.
1) Ed Murashie is no longer making his excellent GRB can feed with a custom designed splitter/combiner. It was far superior to the septum feed that I built. I think it died due to lack of interest. There are an extremely small number of people with the desire to build a GRB ground station. I only get about 1 or 2 requests per year from people wanting to buy a copy of my program - "GRB Imager".
2) The Digital Devices Cine S2 V7A is no longer being made. It worked well for GRB.
3) The TBS6903 is being replaced by the TBS6903X with a different chipset. This new card does not work with GRB, and it likely never will unless the demodulator chip manufacturer releases the detailed specifications and register information to the public.
There may be a small remaining stock of TBS6903's somewhere. But I just heard from a guy who ordered a TBS6903 direct from TBS and sent him a TBS6903X instead.
This all means that it may no longer be possible to obtain a new DVB-S2 card for GRB use. And you are left with the choice of either building your own septum feed or purchasing one from RF HamDesign.
3 months later....
I signed an NDA for the chip used in the TBS6903X (the STiD135) and got the documentation I needed. With it, I was able to get it working with GRB. But the reception quality is not nearly as good as the older TBS6903 (with a different chipset). I would consider the error rate from the TBS6903X borderline unusable for GRB,
I will try some different amplifiers and see if it helps.
I signed an NDA for the chip used in the TBS6903X (the STiD135) and got the documentation I needed. With it, I was able to get it working with GRB. But the reception quality is not nearly as good as the older TBS6903 (with a different chipset). I would consider the error rate from the TBS6903X borderline unusable for GRB,
I will try some different amplifiers and see if it helps.
Something I've never seen a satisfactory explanation for -- what on Earth do hardware makers gain by diminishing their potential purchaser pool by making their hardware difficult to develop for?
Nothing that I can think of. I can understand having an NDA for chips that have not been released, but leaving it in place after release makes no sense.
But I will, of course, honor the NDA I signed and keep it secret.
I have temporarily given up my attempts to get the TBS6903X to work well with GRB. Part of the problem is that my code to read and write to the STiD135 registers is flaky -- sometimes it works and sometimes it doesn't. I don't know why.
The best performance that I have gotten out of the TBS6903X is about 1 error per 400,000 baseband frames. That may sound good on paper, but compares poorly vs. the older TBS6903, which has an error rate of about 1 in 40 million.
Another problem is that my TBS6903X does not work after a cold start. It requires a cold start followed by a restart in order to work.
The older TBS6903s are still available on Amazon. So hopefully they will remain available for a very long time.
The best performance that I have gotten out of the TBS6903X is about 1 error per 400,000 baseband frames. That may sound good on paper, but compares poorly vs. the older TBS6903, which has an error rate of about 1 in 40 million.
Another problem is that my TBS6903X does not work after a cold start. It requires a cold start followed by a restart in order to work.
The older TBS6903s are still available on Amazon. So hopefully they will remain available for a very long time.
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