Smallest EMWIN antenna
- Thread starter sammyizimmy
- Start date
- Latest activity Latest activity:
- Replies 380
- Views 44K
- Status
USRP1. I've already sold all of the daughterboards except the DBSRX2 (800-2300 rx only). I'm going to get a NetSDR+ after I sell the USRP1.
Great News Joe! - Thanks for your testing!!! I'm eager to get my hands on your decoderIs there any ETA of a release?
The HDSDR file is about the same quality wise. Has periodic disruption due to noise. There were only 3 files successfully received in that file. The reason is that a graphic was also being transferred and that occupied most of the virtual channel - unfortunately the entire file was not contained in the wav file.
So, with the original file I will do some work to see if things can be improved a bit. After that, i will send you a link to download the decoder - it will be in trial mode and will work for 15 days. You need to down load at least the ENWIN ingestor from Weather Net - i believe that is free. I do recommend the rest of the software as it will automate the file processing for you. With that said, I would not do anything but the trial from Weather Net initially to insure you are happy with everything. The periodic noise is something you will need to solve for error free reception.
Stay tuned.
Joe
OK, so i made some changes - when you are not experiencing some form of interference the viterbi corrections are < 375. This is about as good as it will get with your setup.
Here is a screen capture of decoder on your file: this is what it should look like when things are working.
https://www.dropbox.com/s/40aa4coo5ab6l2q/emwin_dedode.PNG?dl=0
If Vit gets too high then RS will kick in and make corrections. If RS goes negative then the frame is not recoverable and LOS will increment.
Once you have the decoder, you should strive to get Vit as low as possible.
I will send you a link to decoder as soon as i package it up. After you are up and working then I am happy to assist anyone else interested.
Joe
Thanks Joe! - To confirm my thought process is correct, the way to lower Vit and thus improve signal is to make adjustments to the antenna (turning it / reducing noise / improving SNR)?
If this is the case, I am planning on doing another peak once I have the decoder with it running on live data in order to optimize things as much as possible with the receive setup.
If this is the case, I am planning on doing another peak once I have the decoder with it running on live data in order to optimize things as much as possible with the receive setup.
Sure, let me get this first one done and then I can get you something. You have AirSpy, correct?
Joe
Sounds good. Yep, I have a spare AirSpy I can use.
Btw, what sort of processor requirement does your AirStreamer program have? I ask because I have a spare industrial computer with an intel core 2 duo processor and a spare outdoor enclosure (one of these: http://bit.ly/1Wmpxz1). I was thinking about mounting it just behind the dish, let AirStreamer run on that and then have the decoder run in a VM on my xen cluster.
Last edited:
AirStreamer outputs 10e6 or 2.5e6 or better said, whatever AirSpy supports. The EMWIN decoder needs 500K so, I either need to give you an older version of airstreamer (command line version) that supports decimation or i need to modify emdwin decoder to also support 2.5e6. That's why I can just send you the bits - i need to test it with modifications.
The AirStreamer without decimation doesn't use a lot of CPU but does require enough speed to keep up with USB at selected sample rate. The AirStream with decimation requires some CPU in order to do the decimation - not sure how much. It will tell you if it can't keep up, it has a FIFO and if it overflows it will tell you. I am leaning toward updating decoder to handle 2.5e6 SR - then you can get away with less CPU if you choose to separate airstreamer and decoder - with that said, it does need to be wired LAN not wireless, UDP packet loss over wireless will impact decoder.
You can download AirSteamer on my website if you want to try it out (the one without decimation) - just use 2.5e6 sample rate for testing CPU load.
Hope that helps.
Joe
Honestly, I'm fine with whatever is easiest for you. I'd actually even prefer a command line version if that's an option. Easier to have a script launch it if the machine gets restarted.
I could also provide a udp stream via SDR-Radio if needed.
I could also provide a udp stream via SDR-Radio if needed.
Last edited:
Update on my end of things.
Joe has put a lot of work into his decoder and it works well. I am still having receive issues despite my clear view of the satellite and I am blaming it on either
1). broadband noise or
2). poor external LNA or
3). cable losses.
My setup currently looks like:
----------------------------------------------------------
TP-LINK ANT-2424B Antenna feed ->
LMR400->
N-female feed output ->
N male coupler ->
LNA Input
LNA (Down East Microwave ATF-10135)
N female LNA output ->
N female to F adapter cable ->
RG-6 (10/12 feet) ->
F to RP-SMA adapter ->
RP-SMA - SMA adapter ->
SMA input of SDRPlay.
----------------------------------------------------------
I have done experiments and different pieces of RG-6 are lossier than others with more noise ingress.
I'm also wondering if there is an impedance mismatch here.
I'm also thinking that power lines are a source of my broadband noise interference and that my LNA is not up to muster / not hot enough (not enough gain).
I've also checked for the possibility that the reflector on the antenna feed was under illuminating the antenna.
I have confirmed that the broadband noise IS coming thru the antenna and not coming from inadequate shielding on the SDR (put it in an aluminum enclosure)
I can put my hand infront of an area of the dish and watch the noise go away.
EDIT: I also just did some testing and took the LNA out of the picture and evidently I am only realizing 5 DB of gain w/ the external LNA - I think this may mean I need an improved LNA. (higher Gain).
Currently I am getting bad viterbi performance as well as frequent signal dropouts.
Kudos to Joe for helping with the testing of this setup and allowing me to be a guinea pig.
I highly recommend his demodulator!
Joe has put a lot of work into his decoder and it works well. I am still having receive issues despite my clear view of the satellite and I am blaming it on either
1). broadband noise or
2). poor external LNA or
3). cable losses.
My setup currently looks like:
----------------------------------------------------------
TP-LINK ANT-2424B Antenna feed ->
LMR400->
N-female feed output ->
N male coupler ->
LNA Input
LNA (Down East Microwave ATF-10135)
N female LNA output ->
N female to F adapter cable ->
RG-6 (10/12 feet) ->
F to RP-SMA adapter ->
RP-SMA - SMA adapter ->
SMA input of SDRPlay.
----------------------------------------------------------
I have done experiments and different pieces of RG-6 are lossier than others with more noise ingress.
I'm also wondering if there is an impedance mismatch here.
I'm also thinking that power lines are a source of my broadband noise interference and that my LNA is not up to muster / not hot enough (not enough gain).
I've also checked for the possibility that the reflector on the antenna feed was under illuminating the antenna.
I have confirmed that the broadband noise IS coming thru the antenna and not coming from inadequate shielding on the SDR (put it in an aluminum enclosure)
I can put my hand infront of an area of the dish and watch the noise go away.
EDIT: I also just did some testing and took the LNA out of the picture and evidently I am only realizing 5 DB of gain w/ the external LNA - I think this may mean I need an improved LNA. (higher Gain).
Currently I am getting bad viterbi performance as well as frequent signal dropouts.
Kudos to Joe for helping with the testing of this setup and allowing me to be a guinea pig.
I highly recommend his demodulator!
Last edited:
Do you have a datasheet for that LNA? I can't seem to find one online. That may not even be the issue though.
I has some trouble with N to F adapters causing issues when I was trying to get my signal straightened out. I ended up grabbing one of these cables since I just needed a short run:
www.amazon.com/gp/product/B000EREM6C
You'll still need the RP-SMA to SMA adapter.
Btw, if any of you gents are interested in a cheap NOAA APT receiver, I just listed a kit on eBay. It's for the lower resolution APT signal but it's still fun to play with. I had to take it down due to our HOA. Oddly enough, there's a provision that allows for dishes in our bylaws. No limit on the number of dishes as long as they are under four feet in diameter. Poor HOA doesn't know what they're in for with me! Anyway, here's the kit:
http://www.ebay.com/itm/331804290102?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649
I has some trouble with N to F adapters causing issues when I was trying to get my signal straightened out. I ended up grabbing one of these cables since I just needed a short run:
www.amazon.com/gp/product/B000EREM6C
You'll still need the RP-SMA to SMA adapter.
Btw, if any of you gents are interested in a cheap NOAA APT receiver, I just listed a kit on eBay. It's for the lower resolution APT signal but it's still fun to play with. I had to take it down due to our HOA. Oddly enough, there's a provision that allows for dishes in our bylaws. No limit on the number of dishes as long as they are under four feet in diameter. Poor HOA doesn't know what they're in for with me! Anyway, here's the kit:
http://www.ebay.com/itm/331804290102?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649
I did an edit above. I am only getting 5 Db gain out of the external LNA ~35/36 Db without it ~29/30 Db with it.
Nice gear you are selling there!
On the adapter front, I have a N-male - RP-SMA adapter cable with RG-59 on it... works but I just noticed it induces noise....
I think the LNA is a BIG part of the issue. That or cable losses. (or bad adapters / adapter losses) - noticed that too with one N-F adapter...
Nice gear you are selling there!
On the adapter front, I have a N-male - RP-SMA adapter cable with RG-59 on it... works but I just noticed it induces noise....
I think the LNA is a BIG part of the issue. That or cable losses. (or bad adapters / adapter losses) - noticed that too with one N-F adapter...
I'm sure there's at least a little loss with the cables and adapters. However, it's not like you have a dozen adapters tossed in there. The N male coupler between the antenna and LNA obviously has to be there. Maybe use a N-Male to to SMA adapter after the LNA and use a LMR-400 SMA extension cable between that and the SDR.
That LNA seems to be the primary issue. It's not exactly a problem since it *is* helping. It's just not helping much. How is the LNA powered? External or via the SDRPlay? If it's the SDRPlay powering the LNA, what voltage does the LNA require and what does the SDRPlay output? If it's an external power source, have you checked to make sure the power supply isn't going bad (Heck, it may even be a source of noise if it's too close and going bad)?
That LNA seems to be the primary issue. It's not exactly a problem since it *is* helping. It's just not helping much. How is the LNA powered? External or via the SDRPlay? If it's the SDRPlay powering the LNA, what voltage does the LNA require and what does the SDRPlay output? If it's an external power source, have you checked to make sure the power supply isn't going bad (Heck, it may even be a source of noise if it's too close and going bad)?
- Status
