Smallest EMWIN antenna

[Joe DC]

Not sure how skilled you are with making circuit boards but if you check out the package outline you will find that it will be extremely difficult to solder this component by hand. Something like an SGA4586Z would be more forgiving in the fabrication department. You will need chip components for the few other parts required for best performance. Try and get most of your gain from your antenna for a better chance of success. A dish will probably be your best bet. The feed can be easily made from an approx. 6"diam X 8" deep large tomato paste can.

 

[FaT Air]

Agree. www.minicircuits.com also has MMIC's that may work. Also available is modular 'blocks'. The only 'hindrance' may be designing the circuitry about the device itself. Impedance matching and the circuitry materials themselves has to be taken into account. Best left to the microwave RF Engineers.

Try and get most of your gain from your antenna for a better chance of success.

That's where the best SNR occurs. SNR cannot be improved with amplification alone.

 

[jdc270]

The location that I would like to install it has no internet or TV. also the "one time cost" appeals to me(but not nearly as much as the technical challenge)
Currently this is sorta what I am thinking
GEOS East -> my antenna -> SDR -> raspberry pi with small touch screen
It's the GEOS East -> SDR that I'm a bit lost, from there I feel pretty cofident that I could handle it(I do c++ and java)

Sent from my Milestone X2 using Tapatalk 2

 

[sammyizimmy]

This dish(http://www.l-com.com/wireless-anten...ini-reflector-grid-antenna-n-female-connector) looks almost identical to the werner labs EMWIN antenna(http://wernerlabsinc.com/antenna.htm).
Perhaps I could use that one? I might have to use a different feed??

Thanks.

 

[sammyizimmy]

Not sure how skilled you are with making circuit boards...

I have done a fair amount surface mount soldering by hand already, I probably need to use a heat gun. I have a few free sample lna's coming from Maxim Integrated(MAX2659ELT+ and MAX2641EUT+). I will try to post updates as I go.

Here are some project I have done (https://github.com/sammyizimmy).

Back to my previous post, does any one have any thoughts or comments on that dish?

 

[Joe DC]

You will end up with about 20dB gain @ 1690 Mhz with the L-com antenna. You could give it a try but unless you do a system analysis using the specs from the LNA and the SDR device taking into consideration bandwith and SNR needed its hard to say if the gain is enough. Again, those Maxim devices look good but you are working with leads that are fractions of a mm apart. Good luck! You might want to consider a GaAsfet preamp instead.

 

[sammyizimmy]

Has any one tried this (http://www.maximintegrated.com/en/products/comms/wireless-rf/MAX2120.html/tb_tab0) for OQPSK or BPSK demodulating? Or is it even possible?

Looks like my grid antenna arrived today!

 

[FaT Air]

Other than it's optimized for 2.4Ghz and you're after 1.7. May see a big drop in performance. But I suppose you could lengthen the antenna elements to resonate at 1.7Ghz.

 

[Stargazer]

The grid dish/antenna for 2.4 ghz looks like what is used for wisp's (wireless internet service providers).

 

[sammyizimmy]

Looks like it has a dipole antenna with about 1.25 inches per side. According to http://www.csgnetwork.com/antennaedcalc.html each side should be 1.6875 inches @ 1692 Mhz.
Could/should I solder on extensions to get the correct length?

 

[FaT Air]

Can't really tell what you're up against in the picture, but I'd do 'whatever floats your boat', either add to by soldering 'extensions' or making a solid one piece unit out of brass or copper. Maybe even aluminum - but can't solder to that.

 

[Joe DC]

Try it as is, then once you get a baseline make changes and see if there is an improvement.

 

[matthewy8]

You can always use solder paste and an oven to do your surface mount projects. It works way better than a heat gun. I don't know which SDR radio you are trying to use but those little usb ones with the separate antenna usually are around ten to twenty bucks and are pretty robust and have a wide receiving range.

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[sammyizimmy]

You can always use solder paste and an oven to do your surface mount projects. It works way better than a heat gun. I don't know which SDR radio you are trying to use but those little usb ones with the separate antenna usually are around ten to twenty bucks and are pretty robust and have a wide receiving range.

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I am using a cheap RTL2832U based sdr but I am not sure if it has enough bandwidth (3.2 Msps) to receive BPSK @ 400Kbps. I am still trying to wrap my head around the concept of i/q demodulators... I think I am slowly getting the drift

 

[sammyizimmy]

FYI. Here is the response I got from NOAA regarding the Telestar 5 EMWIN up-link.

EMWIN is no longer uplinked on Telestar 5. Sorry for the confusion, we'll have to remove that from our web pages. The broadcast on Telestar 5 was a rebroadcast from the EMWIN
broadcast on the GOES I series of satellites. When they were retired the broadcast was ended. Telestar was providing the broadcast as a free public service and when our modulation and
data rate changed they decided to drop the stream.

Sorry for the confusion

 

[sammyizimmy]

Still slowly trying to wrap my head around everything. I found the ADRF6820 (http://www.analog.com/static/imported-files/data_sheets/ADRF6820.pdf) and the STV0299B (http://pdf.datasheetcatalog.com/datasheet_pdf/sgs-thomson-microelectronics/STV0299B.pdf). Would using these two together work and give me demodulate BPSK data? Or would I be better off processing the I/Q data from the ADRF6820 in a FPGA? (Looks like the STV0299B is more or less obsolete is there an alternative?).

So my question is this
antenna -> LNA -> I/Q Demodulator (ADRF2820) -> BPSK Demodulator (STV0299B) -> USB controller
or this
antenna -> LNA -> I/Q Demodulator (ADRF2820) -> BPSK Demodulator (FPGA)-> USB controller
or both won't work, use something else?

 

[outatyme]

Sammy, Did you ever make anymore headway with this? I have 3 of the SDR dongles (2xR820T and 1xE4000) - tried out the R820t's at 1691mhz with a grid parabolic dish similar to yours that has a type N female on it.

My current setup looks like this:
ANT FEED (N FEMALE) -> N-male to N-male adapter -> N-male to rg316 MCX adapter -> R820T SDR dongle

Looking at the spectrograph /waterfall in the SDRSHARP (SDR#) application I think I might have seen and EXTREMELY weak signal from GOES-13.

I have a 1691MHZ LNA (Low noise amplifier) on order and should get it Fri or Sat.
I'm not sure if it is normal for the emwin-n signal to be so weak (pretty much not visible) without any amplification.

These grid parabolic antennas are the same thing that werner labs is using in their commercial emwin setups and selling for $499!!!! - No idea if their feed is any different internally though (tuned to / built for 1691mhz for example).

I am unable to do any testing with the E4000 dongle due to it having a F type connector on it.

It should also be noted that these SDR TV tuner dongles are meant for 75ohm impedance - These Wifi antennas with their type N connectors and 50 ohm coax will probably have an impedance mismatch.
Not 100% sure of the effects this will have but I know folks will get weaker signal.

not really thrilled at the results I've gotten so far with the rtl2832/r820t SDR dongle and this antenna - it's probably because I dont have an LNA right now that I don't see hardly anything in the spectrum waterfall.

 

[outatyme]

I've also got a twinhan 102g tuner card that I could theoretically test with.

 

[outatyme]

SDR dongles seemed dead @ 2.4GHZ wifi frequencies with this antenna too - Pretty sure they can only tune to 2200mhz though. so thats probably why.

 

[outatyme]

Also see http://www.dslreports.com/forum/remark,21216147