Smallest EMWIN antenna

[doubleohwhatever]

Well, I've now found a downconverter for just under $1000:
winradio.com/home/g400.htm

Still more than I'm willing to pay but at least now I know there's another option other than Quorum.

 

[outatyme]

Awesome! - I am so excited I am not the only person interested in this!!!!

 

[outatyme]

The thing is we should not necessarily need a downconverter - if it turns out we are stuck needing one, then this seems to be a software limitation. The goes-r downconverter IS open source I do believe - not that I'm not willing to use USA-SATCOM's stuff I'm just saying.

Uh huh, open source:
http://www.goes-r.gov/users/docs/EMWIN_HRIT.zip

 

[doubleohwhatever]

Yep, it's open source. Unfortunately I'm a PHP developer. I have very little experience with C++ (which I'm assuming is what that software is written in) outside of micro-controller programming.

For anyone interested, the dartcom usb receiver/software is $3700. It's designed to work with the feed/downconverter from quorum which costs $1900.

 

[doubleohwhatever]

Found a cheaper downconverter:
hsmicrowave.com/page46.html

Unfortunately they never pick up the phone and don't return messages. I've tried the past two days. Phones calls and a email. Based on the address, I think it's one guy running a business out of his home. There's nothing wrong with that but if he doesn't ever return sales calls or emails then what's the point.

 

[doubleohwhatever]

Well, I've tried pretty much everything at this point with the hardware I have on hand. I've ordered a downconverter and I'll see what I can do with that when it gets here in a couple of weeks.

 

[outatyme]

Same here. I have focused on trying to spoonfeed parts of the SETI data from goes-13 into one of the existing public demodulators with no joy.

 

[doubleohwhatever]

I'm thinking it might be easier if I use a 1.2m dish instead of the grid antenna/dish I'm using now. Basically, I think you can get away with the grid antenna if you're using a very good LNB or a LNA with receiving hardware tuned for ~1692. With hobbyist gear, I think the larger dish might be needed.

 

[kt4wo]

Well...I can now say that the SDRPlay hooked to the feedpoint of my mesh dish will/does work. I am seeing a signal right where
it should be. I have recored a IQ file for Joe and wait to hear back on if he can decode the EMWIN data from it. My dish is a Laird DC24(40x24")...I had
an extra feed and cut it open and reworked for 1700Mhz(was just a dipole inside). This dish was for a PtP wifi link, but the Laird spec sheet
said it would go down to 1700Mhz(close enuff!!)

Just an update
Trip - KT4WO

 

[KE4EST]

Pretty cool!!
BTW, Trip you are not far from me, I am in Murphy.

 

[kt4wo]

I just moved a few month back...was on Needmore(near gorge) now on Barkers Creek just outside of Dillsboro.
Have a good view of the S sky...except....for TREES!....haha ....
But,,,I have a big chainsaw, so plan on fixing that issue.

Trip - KT4WO

 

[outatyme]

Nice!

 

[doubleohwhatever]

I had
an extra feed and cut it open and reworked for 1700Mhz(was just a dipole inside).

That's almost identical to the dish I'm using. Do you have any photos of your feed modification? How much did it help with the signal?

 

[kt4wo]

I did not try it with the 2.4Ghz feed....since I had an extra one. I will take a few shots this eve when
I get home and post for ya. All I did was use a thin strip of copper flashing(cut from a sheet I had) to add length to the
exsisting dipole and reflector.(It is just a etched board inside, so I just soldered the extra copper to it then trimmed)


I really don't know if the signal I am RXing is strong enough...as I have never done this...but it does "stand out" from the background
on the waterfall. I don't recall exactly...but it seems it was 100-150K wide????Maybe??.

Trip - KT4WO

 

[doubleohwhatever]

Btw, since you've been in contact with Joe/usa_satcom, has he said anything about releasing his software?

 

[usa-satcom]

Hello,

EMWIN software as well as LRIT will be available soon.

EMWIN is a stronger signal from GOES (versus LRIT, which requires larger dish). The smallest dish i have tested it with is 1.2m. I have only tested with AirSpy and RFSpace SDRs. Others are possible but require someway to get IQ data on the network - as that is the interface the decoder expects.

EMWIN uses viterbi as well as RS error correction and so you can get away with a fairly low signal, about 5dB is absolute minimum. If you want 24x7 operation that is error free, probably a few extra dBs for margin.

An LNA is a must with any usual SDR, as the NF are just too high at l-band.

Joe

 

[outatyme]

Great work on your decoder Joe! I am a big fan of yours!!!! - I just didn't want to be a thorn in your side.

 

[outatyme]

It will be interesting to see other folks RX rigs. (dish, feed etc.)

 

[kt4wo]

OK...here are a few pics of my setup....very, very basic and as it turns out,,,,about 2db too low.

 

[kt4wo]

I will try rotating the feed/dish/house to get a better signal....But Joe said what I have now is not enuff.
If that does not work.....then time for a LNA or ......BUD.
Trip - KT4WO