GOES 16 GRB downlink vs GVAR

[GOES 12 GVAR user]

Thanks, it was refreshing to see some real signals and not artifacts.

That's a great comment

Any suggestions for ready to use software to view the data?

The software link I posted in post # 21, it requires CentOS Linux and you'll have to download it to see the requirements.
When I downloaded an earlier version the computer requirements was somthin to decode this.
That's otherwise part of the problem with this type of data.

 

[GOES 12 GVAR user]

You still got time, go after GOES 16.

Any idea what the dozens of signals from 1679 to 1680 are? They are all low bandwidth, and some are intermittent.

That I don't. If they go away when you move the dish higher in elevation... then they are coming from the ground as some sort. Otherwise disconnect the dish and see it they are still there with no antenna.

 

[N6BY]

You still got time, go after GOES 16.



That I don't. If they go away when you move the dish higher in elevation... then they are coming from the ground as some sort. Otherwise disconnect the dish and see it they are still there with no antenna.

When I move the dish those signals from 1679 to 1680 go away. So I am certain that they are not ground based. Also, I see them on both 135W and 89.3W.

... As for the software referenced in post #21 -- I am looking for programs that get their input directly from an SDR. ( I realize that this is not possible with GRB since its DVB-S2.)

 

[GOES 12 GVAR user]

Any idea what the dozens of signals from 1679 to 1680 are? They are all low bandwidth, and some are intermittent.

I just thought about it and from 1679-1680 MHz I think is DCS. Data collection platform.That's on the Left side of GVAR and GRB.looking at the spectrum.

I am looking for programs that get their input directly from an SDR.

Your on your own trying to feed that into the SDR. I am aware of none as of yet.

 

[GOES 12 GVAR user]

I'm about positive that's DCS. That's where you see those beam antennas along the roads at creeks, rivers (remote stations) and that data is sent to GOES then relayed back to NOAA for processing. River gauges, buoys, and other remote sensing uses it.

 

[GOES 12 GVAR user]

So.. if the image that you put up is from GOES 16 GoesEastGRB,jpg
That's GRB. It's a massive wide signal.
I see..the first 3 images are of the GOES 16 spectrum. Ahh said the blind man.

And GoesWestGRB.jpg that's DCS, GVAR.

Looks good.
I'm out for the night, been a long day.

 

[N6BY]

...
And GoesWestGRB.jpg that's DCS, GVAR.

Looks good.
I'm out for the night, been a long day.

Definitely, but Sunday is even longer! (25 hours since we are going off daylight savings time)

Now if I could just get that Open Satellite software to compile.....

 

[GOES 12 GVAR user]

N6BY,
On my drawing the probe length is correct in decimals, the inches is wayy off. The 1 5/32" SHOULD be 1 21/32" A little over 1 5/8".
I sat down and measured the horn out after all this to make shure it's right.
I thank you for catching that, I uploaded that drawing at another post on this site well before you caught that inaccuracy.
I drew it quickly and missed those errors. I contacted the site hopefully it will get fixed, I will upload the proper dimensions I use here soon. (new drawing)
Another bit of info that I did more research on those probe positions and even in the microwave handbook I found different positions in wavelengths from the back.
So with all that, here's the info: generally

Horn dia: .75 of a wavelength = 5"
Probe distance from back: 1/2 wavelength = 3 5/16"
Probe length: 1/4 wavelength = 1 5/8" a little over (1.656")

How's the luck with compiling that software going?
Computer code, one way to go bald quickly.

 

[N6BY]

The dimensions you get depend on which book you're reading.

In the ARRL Antenna Handbook on page 15-61 says "An inside diameter range of about 0.66 to 0.76 wavelength is suggested." At 1690 MHZ I calculate a wavelength of (300/1690)*39.37 = 6.99 inches. If you use the middle of the suggested range (0.71) you get 4.96 inches. So our 5 inch diameter is very close to the middle of the suggested range.

On the same page it reads "The wavelength in a waveguide always exceeds the frequency wavelength and is called the guide wavelength." Using the formula given on that page, with a can diameter of 5 inches I calculate the guide wavelength to be 12.16 inches -- significantly more than 7.02!

And another surprise - "The length of the feed should be two to three guide wavelengths." In our case, that would be 2 to 3 feet!!!

...
Computer code, one way to go bald quickly.

Most definitely! On the software end, I was able to get the Open Satellite Project code to compile, but I had to make several changes and the end result was a program that didn't work. You have to compile several programs, and each program requires separately compiled libraries. And some of those libraries require other libraries. All in all, very complex, time consuming and lots of room for error. So I'm not surprised it didn't work.

So.... I contacted Joe from USA-Satcom today and he was nice enough to send me a 15 day trial version of his XRIT decoder. I told him I had an SDRPlay and an Airspy. He suggested that I use the Airspy, and use their 'Spyserver' program to stream it to his decoder. His program is able to connect with Spyserver, but it seems to get stuck trying to set the frequency. I spent about an hour trying to get it to work and gave up. Will try more tomorrow and maybe contact him if I'm still stuck.

.... When GOES East moves to 75W, do you think you will still be able to get GRB with enough SNR, Tim? If its marginal while its at 89.5, it may be out of reach from your location when its at 75W. Might need one of those 4.5 meter dishes.

 

[GOES 12 GVAR user]

Cheap china box info: Don't work for this.
As we thought the cheap china box won't work. It was worth a try.
It does work for the TV channels though.
So doing some research pretty much concludes that none of the others like above will work. Which means the S300 looks like the best choice. Checkout price of 600.00 is steep but when working with these weather satellites that really isn't a big price. I will say as being an owner of one they are very easy to set up and the interface program will run off the CD disk or on any OS as it's not OS dependent. The most difficult part of it is the set up of the network interface. If you do this type of thing all the time it would be a breeze.
So.. In this forum we have determined what dish will work (size so far) and a receiver. I'm pleased with the results as it's been better than expected. And we have determined that all kinds of things can be used when making a feed for this purpose (thanks to N6BY, for coming up with an impressive solution to the problem)
As for the waveguide length, I think there is a minimum but the max is far beyond the scope of this discussion as waveguide is a form of transmission line.
I do recall since you mentioned that guide wavelength
but don't recall that in the the microwave handbook, guess I got to go back to the books!
N6BY you have given me an idea for that next feed I plan to make for this. I can make a prototype much cheaper using your method of construction. Though I will consider using copper foil as it has better properties then aluminum.
I will get the info of that feed up here shortly with the proper dimensions.
The feed will be around 2 feet long and uses a septum polarizer to create bolth circular polarization's. The guys at 1.2 GHz and 2.4 GHz use them.

.... When GOES East moves to 75W, do you think you will still be able to get GRB with enough SNR, Tim? If its marginal while its at 89.5, it may be out of reach from your location when its at 75W. Might need one of those 4.5 meter dishes.

XRIT, That's a LRIT decoder isn't it?
I can't answer your question as I don't have an answer but..
If it was me in your position this is what id do.
Since you have a working setup now I would try to see GOES East from your location and compare it to GOES West. If you can see Goes East and it's comparable to West then it should be possible to continue trying to acquire GOES R data. But I don't know how low your elevation will be to see GOES East from there and any other issues.
If your still using linear polarization remember to rotate the feed for best polarization match as swinging like that will have the polarization be off possibility.
If you see 2 dB or greater in signal drop then you will have issues. (My thought)
I think it's possible as you can see GOES R from there now and GOES East is just a little farther to the East of that.
The question that hasn't been answered yet is.. Do you currently have enough C/N (DVB-S2) now with that dish?
Then if so, how much?
From what I'm seeing that only fringe locations need that 4.5 M dish as most US locations should be able to get away with a 3 M (10') dish. 12' at the most in the US mainland. From what I'm seeing here (my opinion).

 

[N6BY]

Here is an image I captured a little while ago of the Northern Hemisphere. You can see Baja California and Mexico on the right. Its overcast over much of the west coast right now.

...
XRIT, That's a LRIT decoder isn't it?

LRIT, HRIT, EMWIN, and DCS. However I wasn't able to test HRIT because Joe says it is currently offline right now in preparation for the move east.

...
The question that hasn't been answered yet is.. Do you currently have enough C/N (DVB-S2) now with that dish?
Then if so, how much? ...

I don't know the answer to that yet. I'm still using a linear (vertical) feed and I need to modify it for circular. After I do that I will post a signal graph and estimate the C/N for GRB while its still at 89.3.

 

[N6BY]

Another false-color image of the west coast today. Rain on the way.....

 

[GOES 12 GVAR user]

I want to make others know that the images above are LRIT not GRB, it's a sub product of GVAR/GRB and..
I will say this "that the old Wefax holds no candle to LRIT."
Good job, since we started this forum you now made a feed and are getting LRIT.
Now imagine being able to zoom down to seeing good detail in the cloud tops, 3/4 Km resolution on the visible image, looking at multiple channels of IR imagery showing water vapor, IR, and other aspects. That's GRB.That's what I'm after.
A couple of images from the GHCC of GOES R GRB at 3:37 AM CST

CH 14

CH 8

There is no visible image as it nightfall so all you see is black.
And that's just 3 channels, there are 7 channels on one polarization alone.
That what I'm after.
N6BY do you have a link to Joe's decoder?
I'd like to keep it in mind as I may try to get my EMWIN station back up after the change over.

 

[N6BY]

I want to make others know that the images above are LRIT not GRB, it's a sub product of GVAR/GRB and..
I will say this "that the old Wefax holds no candle to LRIT."
Good job, since we started this forum you now made a feed and are getting LRIT.
Now imagine being able to zoom down to seeing good detail in the cloud tops, 3/4 Km resolution on the visible image, looking at multiple channels of IR imagery showing water vapor, IR, and other aspects. That's GRB.That's what I'm after.
A couple of images from the GHCC of GOES R GRB at 3:37 AM CST...

Yes, the images I posted are indeed LRIT.

Unfortunately, I think direct GRB reception by hobbyists like me is 'unobtainium' for the foreseeable future. I'm not going to spend $600 for a Novra S300 (required for Generic stream DVB-S2). And when GOES-16 moves east I'll be way out of the satellites beam. But for you, being farther east in Iowa there is a chance of getting enough signal for it.

N6BY do you have a link to Joe's decoder?
I'd like to keep it in mind as I may try to get my EMWIN station back up after the change over.

Joe's decoder is at: USA-Satcom | Monitoring worldwide communications on HF through Microwaves… You have to contact him for a 15 day trial version. The license costs $100, which seems quite hefty since a substantial portion of the software is open source, which Joe acknowledges. It requires an Airspy SDR.

 

[GOES 12 GVAR user]

A continuation from the last post
Visible image from the GHCC of GOES R GRB at 3:06 PM CST.

CH 2

Unfortunately, I think direct GRB reception by hobbyists like me is 'unobtainium' for the foreseeable future.

It's a lot less unobtainium than it used to be. As I stated in the first post, most don't or can't use this level of data.
Most are happy with LRIT. Nothing wrong with that as it has gotten much better over the years.
As I also stated the cost has come down a lot from what it used to be.
I spent 4 digits on my GVAR station so most don't want to put out that kind of money to see satellite images on the hobbyist level. Clearly understandable.

But for you, being farther east in Iowa there is a chance of getting enough signal for it.

I count on it, I bought the receiver for GRB today.
In about another 2 years GOES West will be replaced with the Goes "S" Satellite "new" type as well. Followed by "T"
See schedule (Goes Satellites)

The license costs $100, which seems quite hefty since a substantial portion of the software is open source

Thanks for the info. As I stated earlier one of the big costs is software, open source or not it takes time to make it. It used to cost $500 for a wefax station at one time.
I will continue to post my progress of the GRB station here.

 

[N6BY]

...
I count on it, I bought the receiver for GRB today.
In about another 2 years GOES West will be replaced with the Goes "S" Satellite "new" type as well. Followed by "T"
See schedule (Goes Satellites)...

Did you buy another NOVRA S300 or ???
And I'm glad to hear that the west coast gets a new satellite too.

...As I stated earlier one of the big costs is software, open source or not it takes time to make it. It used to cost $500 for a wefax station at one time.
I will continue to post my progress of the GRB station here.

Looking forward to your progress reports.

I've been employed or self-employed as a software developer since 1984. So I understand the software cost issue, especially when its niche market. Without the volume the cost has to be high.

... I have a TBS6983 DVB-S2 PCI tuner card. I am going to see if I can get it to lock the GVAR stream on 135W. If it locks I will have transponder stream that I should be able to find a way to process.

 

[GOES 12 GVAR user]

Did you buy another NOVRA S300 or ???

Yes, I did buy another Novra S300 today.
It's my first big purchase for this upgrade.

The west coast was always going to get a new satellite as well, it was where the first "new format" one was going. Yep, NOAA has 2 more being built right now. One to replace West and one as a spare.
"R" was the first, It was to be the test pilot in this new series of satellites. The only question was... which satellite was it going to replace?
At no surprise it's replacing East. GOES East has only been using part of the GVAR product as a failure had occurred some time ago to the electronics that blinded the sounder. GOES East has been operating in a degraded condition for some time now.
So far the way it looks by the time "S" is ready to be sent up most of the bugs will have been worked out and the transition should be very smooth.

I'll keep everyone reading up to date on how it's coming here. This project will continue over the next 6 months. Winter is almost here so it will limit some of the work outside.

Without the volume the cost has to be high.

Well said.

... I have a TBS6983 DVB-S2 PCI tuner card. I am going to see if I can get it to lock the GVAR stream on 135W. If it locks I will have transponder stream that I should be able to find a way to process.

Go for it, The GVAR stream can be acquired by a 8' dish but the margin will be very close so be advised. 2.11 Mbps BPSK at 1685.7 MHz. GVAR is not DVB format. If you can dabble in it you will get a real good idea of what GRB is.

 

[GOES 12 GVAR user]

I'm going to post info on the GRB computer required for this as it will soon have to be addressed.

First: Minimum System Requirements for the CSPP GRB Version 0.3 prototype software are as follows:

*12 Core, 2.4 GHz CPU W/64 Bit instruction support
*32 GB Ram
*CentOS 6 64 bit Linux (or other compatible 64 bit Linux
distribution),
*100 GB of Hard disk, Storage space.

That's a Intel® Xeon® E5-2695 v2 Processor or equivalent

Installation instructions download (see below)

As I said this computer is something to see.
This computer would leave my GVAR computer in the dust.
Also this is just the file stream processing computer not the display machine. Though it can do quick views of the data.
Plotting the images is a whole other process and machine.

Already got a quote for a machine more than this and it's wasn't as bad as I thought it would be. I'll be getting more quotes in the future.

 

[N6BY]

...GVAR is not DVB format...

My mistake, I got all those formats and acronyms mixed up. What device goes between your antenna and computer to receive GVAR?

...
That's a Intel® Xeon® E5-2695 v2 Processor or equivalent ....

Around $2K for just the CPU, wow. But at least the software is free.

 

[GOES 12 GVAR user]

What device goes between your antenna and computer to receive GVAR?

You need a BPSK (Bi Phase Shift Key) receiver. The demodulated output is fed into the software for making the image files.
Sometimes called a modem. I don't know where to get one at least cheap. This is one of the problems with GVAR data.
If you can come up with one then all you need is a software solution.
Can you decode the stream with a software demodulator like LRIT, HRIT, EMWIN ?
I don't know the answer to that question.
But I do know it's bandwidth must be better than 2 OR 4 Mhz wide, I think the latter.

On the computer...
The quote I got came in lower then that, but it may not be that processor. As I said I will have to get more quotes.
And if I only process one stream as planned the requirements need not to be that demanding. But it's something to keep in mind in the future as requirements might increase. Also the NEW software release may not need all those requirements but I don't know that.
Yes, CSPP making that software cuts the costs a big way. That software is a bank breaker right there.