Smallest EMWIN antenna

[outatyme]

no response out of him - I understand he has been in the hospital though.

 

[sammyizimmy]

Sorry to hear that. I'm still slowly working on the pcb layout.
Here are some screenshots of my work. any comments or suggestions would be welcome.

 

[outatyme]

It's been abit - I've had to move. I did Order samples from maxim and did receive the sample of the tuner IC.

 

[sammyizimmy]

Yeah I've had some thing going on too. But I still haven't given it up. I am looking at the TMS320C6746 and ADS4222 to replace the microcontroller, fpga and adc. (Plus! Free samples of those.)

 

[sammyizimmy]

Just in case any one is wondering, I am still working on this project. Here are some pics on dropbox of what I've got so far.
I did a total redesign, sorta basing it on the BladeRF. The flow is something like this: Antenna -> rf switch -> LMS6002D -> OMAP-l138 -> PC.
Due to some design errors I had to scab on an extra 1.2v power supply, and I can only get 4MSPS(I used the gpio, I'm guessing I could get at least 20 MSPS using the UPP on the OMAP-l138, but that will require a new PCB). I am currently trying to figure out the LMS6002D chip and all it's settings. Here is a screen shot of what I am getting so far (tuned to 400MHZ ):

I am guessing I have some filtering/gain/whatever issue. I am planning to make every thing open source, but I haven't got enough stuff polished up yet to put it on github. If any one is very impatient and want's the schematic/pcb drawing/code and all it's flaws PM me.
Any suggestions/recommendations/tips are welcome.

 

[outatyme]

Way to go! I got curious about what happened! I'm still highly interested and want to contribute however i can. I have my grid parabolic mounted on the base of a tower now and have been waiting for the receiver

 

[sammyizimmy]

Here are two wav files I recorded with the hackrf and a lna I build myself. Do you think the signals are strong enough to be decoded?
I have no experience in demodulation oqpsk, viterbi and reed solomon using gnuradio. Is there anyone out there that could guide me?

These are 2Msp wav files:
lrit,1691MHz -> https://www.dropbox.com/s/c1l58t2ggx4x5ed/27-Apr-2015 074055.960 1690.800MHz 000.wav?dl=0
emwin,1692.7MHz-> https://www.dropbox.com/s/pu69n8wtc0ddvcl/27-Apr-2015 073918.627 1692.600MHz 000.wav?dl=0

Here is what I've been experimenting with.

The results:

 

[outatyme]

I finally got a Sdrplay, Fabricated a mobile mount for my grid parabolic and was able to pull in the emwin-n signal on 1692.700 mhz from GOES-13 and GOES-14.

I was also able to confirm that the e4000 RTL-SDR dongle CAN receive this frequency with a suitable LNA.

I also tested two R820T's and they ***COULD NOT*** see the signal even with a suitable LNA.

I now have the signal permanently acquired but have not made much headway with processing it.
This is the area I need help with.

Here are some links to some tools and resources I've encountered so far:

This individual has written some working software which does what we want.
I asked him about obtaining a copy of it and was told it wasn't ready yet.
I really *REALLY* wish we could get some help from him on our project.





https://twitter.com/usa_satcom/status/630587676526145536
https://twitter.com/usa_satcom/status/630143954508320768
https://twitter.com/usa_satcom/status/628747552406441986

Weather message software for processing the files is here:
There is also a software demodulator here but I haven't been able to get it to work when I feed it audio from sdrsharp through virtual audio cable. It never sees the CCSDS packets...
http://www.weathermessage.com/Downloads/WeatherMessage.aspx

 

[doubleohwhatever]

Has anyone gotten any further with this?

 

[ayelvington]

Nice to see that there is still interest in EMWIN. I sold my system in 2009 when I retired from the Coast Guard, and I wasn't inclined to spend the $ to migrate to the new system. FYI, I ran it on a 1m dish from my apartment balcony in Arlington VA. I use the Internet data stream now feeding into Weather Message.

 

[kt4wo]

Has anyone had any luck with this?? I have the SDRPlay and a 1-m dish with homebrew feed. Just moved to a new home so havent tried RXing
EMWIN yet with the SDR(its new to me...tried RTL donggles in the past with NO luck) How about that software decoder above???

Thomas - KT4WO

 

[doubleohwhatever]

Well, I was able to get a good signal. Unfortunately, I'm experiencing the same issue as outatyme experienced with the software demodulator. It just never sees the CCSDS packets.

 

[doubleohwhatever]

At the moment I'm using a e4000 dongle. It's the only spare SDR I have on hand at the moment. On Monday I have arriving an airspy and some SMA adapters that will let let me put an LNA (and the airplay) right next to the antenna. I'll report back if this changes anything with the software demodulator.

In other news, I hooked up my USRP1 with the DBSRX2 daughterboard (800-2300 MHz). I tried this with the HRIT/EMWIN software from goes-r.org. The software defaults are designed to work with a downcoverter but you can adjust the frequency manually. Unfortunately I have been unable to get it to see the signal at 1692.7. I'll try this configuration again once I have the LNA installed right next to the antenna.


As a side note, I can also confirm that R820T based devices cannot see the signal (even with a good LNA) no matter what the advertising says about range.

 

[kt4wo]

Maybe this week I can hook the SDRPlay to the feedpoint and check for a signal. Been in our new home for about 2 months and most
of my stuff is still in boxes!!

"goes-r.org"
What software? ....I am new to this and finding info re EMWIN has been spotty at best.

Tnx de Trip - KT4WO

 

[doubleohwhatever]

goes-r.gov/users/hrit-links.html

No luck with moving the LNA right next to the antenna. It helped the signal by a very small amount. I sort of figured this would be the case since I was only using 6 feet of low-loss cable to begin with. I'm going to get a downconverter and see where that gets me.

 

[doubleohwhatever]

If anyone has a lead on a 1.7GHz LNB please send me a PM. I refuse to pay $1500 for a Quorum unit.

 

[outatyme]

There are apparently two different demodulators out there in the wild that I have ran across. - I can't get EITHER of them to work correctly.

I don't know if it is an issue with not enough gain (weak signal) or what.

I also figured out from someone who processed the signal by hand in matlab (Andrew Casper) that SETI has some canned signal samples from their satellite array of both the EMWIN (OLD format FSK / no longer broadcasted) and EMWIN-N (OQPSK) signal formats. I fed samples from those into both the demodulators that I have found on the internet and no dice.

This is nothing but a software or signal problem plain and simple.

Right now I am thinking software due to my testing with the SETI files which a person WAS able to manually demodulate in MATLAB! - Yet the two publicly available demodulators don't work.



There is the demodulator from here:

http://www.weathermessage.com/Downloads/WeatherMessage.aspx
("EMWIN Software Demodulator Repackaged NWS installer.")
​

and there is another demodulator here:

http://www.goes-r.gov/users/hrit-links.html

http://www.goes-r.gov/hrit_emwin/HRITSetup_ 05_2011.exe
(http://tinyurl.com/hritsetup
(Tinyurl link incase goes-r.gov link is broken)

http://www.goes-r.gov/users/docs/EMWIN_HRIT.zip​

USA-SATCOM built a working demodulator for emwin for his Airspy but last I heard he was still working on it.
(I haven't asked in a long while since I didn't want to bug him.)
(The last I saw on twitter he was pulling images and text out with his Airspy setup though.)

http://usa-satcom.com/
https://twitter.com/usa_satcom​

Here are links to Andrew Casper's website who processed the signal by hand in MATLAB w/ SETI samples:

http://www.acasper.org/2011/10/24/goes-satellite-decoding/
http://www.acasper.org/2011/11/15/goes-emwin-n-decoding/​

Links to the canned / archived GOES SETI DATASETS that Andrew Casper used to manually demodulate / process the signal in MATLAB:

http://setiquest.org/wiki/index.php/SetiQuest_Data_Format
http://setiquest.org/forum/topic/new-datasets-posted

http://setiquest.org/setidata/data4/download/2010-09-24-goes-11_1/
http://setiquest.org/setidata/data4/download/2010-09-24-goes-13_2/

http://setiquest.org/setidata/data4/download/2010-09-24-goes-13_2/2010-09-24-goes-13_2-8bit-01.dat
http://setiquest.org/setidata/data4/download/2010-09-24-goes-13_2/2010-09-24-goes-13_2-meta.txt

http://setiquest.org/setidata/data4/download/2010-09-24-goes-11_1/2010-09-24-goes-11_1-8bit-01.dat
http://setiquest.org/setidata/data4/download/2010-09-24-goes-11_1/2010-09-24-goes-11_1-meta.txt​

You can open these in GNURADIO and convert them into different formats
(for example so that you can look at the canned data in SDRSHARP on the waterfall)
if there is any interest in anyone doing that, I will post some instructions.
I tried converting the data into many different formats and feeding it through the two publicly available demodulators and no dice!

I really hope that we can get some community interest behind this and create / figure out an open source working solution to using a 1 meter grid parabolic dish and using a commonly available SDR to acquire the signal then figure out a way to process / demodulate it.

Right now it seems that the RTL-SDR w/ e4000 tuner and the Airspy or Sdrplay should be good to go with this and I CAN confirm that I can pull in a pretty strong signal with a 1 meter grid parabolic wifi antenna and a L-BAND LNA (1690-1700 MHZ).

Demodulation / signal processing is where I and apparently others are stuck at.

 

[outatyme]

At the moment I'm using a e4000 dongle. It's the only spare SDR I have on hand at the moment. On Monday I have arriving an airspy and some SMA adapters that will let let me put an LNA (and the airplay) right next to the antenna. I'll report back if this changes anything with the software demodulator.

In other news, I hooked up my USRP1 with the DBSRX2 daughterboard (800-2300 MHz). I tried this with the HRIT/EMWIN software from goes-r.org. The software defaults are designed to work with a downcoverter but you can adjust the frequency manually. Unfortunately I have been unable to get it to see the signal at 1692.7. I'll try this configuration again once I have the LNA installed right next to the antenna.


As a side note, I can also confirm that R820T based devices cannot see the signal (even with a good LNA) no matter what the advertising says about range.

Your testing would be very helpful! I am hoping you have some more success than I have so far!!!

 

[doubleohwhatever]

I came across this just now:
nf3v.com/wp/?page_id=199

It seems he was able to get the HRIT/EMWIN software from goes-r.org to work with a USRP1, a LNB downconverting the signal and a good LNA to boost the signal.

Now, I have a USRP1 but I don't have:
1) a LNB/downconverter
2) The 130Mhz range daughterboard for the USRP.

So I know for a fact that particular bit of software can function. The question is whether it *requires* the signal to be downconverted. The frequency is adjustable but there's no indication of that's just to tweak the center frequency for different downconverters or if you can set it to 1692.7 and have it work with a very strong signal.

I have a better LNA arriving on Thursday and I'll play with that then. Unfortunately I just can't find a reasonably priced LNB/downconverter.

 

[kt4wo]

RE:"USA-SATCOM built a working demodulator"

I spoke with him over the last few days and he does have it working. I have the SDRPlay and ask about support for that. He is looking into it, as he does not have one I have offered a loan of mine.

As I said above, I just moved so haven't had time to check for a signal. I am hoping that with my 1-m dish and the SDRPlay at the feedpoint I will see something. USA-SATCOM said his software is not free but the price is more than OK with me(on a VERY low budget!)
I brought my SDRP to work today and per USA-SATCOM I will be working on getting SDR-Console to stream UDP packets.
He said that would be key to getting it to work with his software.
Will keep ya'll uptodate.

Trip - KT4WO