[amsat-bb] Outernet L-Band Service

Rick Walter wb3csy at gmail.com
Sat Oct 22 18:37:36 UTC 2016

Thank you for the replies to my questions from a couple of people. The azimuth aiming difference between the two programs is more than my magnetic declination but i'll look at the math again. 

I really did not expect to hear the bird with a simple discone antenna without a pre-amp but was surprised to see a fairly strong signal using the Funcube Dongle Pro plus. A friend who lives about 3 miles away checked the frequency with his equipment and hears nothing. I figured it had to be local. It may be coming from my Comcast Gateway or telemetry from a local water pumping station.  I realize you need the SDR mentioned by the outernet docs but thought I would try the FCD for the fun of it. 

As always, there are great threads on this bb. Some may say this has nothing to do with amateur radio satellites but I say wait until we get that geosynchronous bird in orbit! This experience will help us in the end. 

Please keep the outernet info flowing. I know it will help many of us. 

Sent from Rick's iPhone 6S
"Great spirits have always encountered violent opposition from mediocre minds" - Albert Einstein

"Any sufficiently advanced technology is indistinguishable from magic" - Arthur C. Clarke

> On Oct 19, 2016, at 5:40 PM, Dani EA4GPZ <daniel at destevez.net> wrote:
>> El 19/10/16 a las 18:03, Rick Walter escribió:
>> Since reading about the Outernet, I am becoming more curious. I have
>> a Funcube Dongle Pro + connected to my discone antenna going into my
>> windows 7 laptop, running SDR Console. I am hearing a signal that
>> sounds like data with about 2-3 second breaks every so often. The
>> frequency is 1,539.793 MHz and I have the decode in Data USB 24 KHz
>> bandwidth. The signal is -60 dBM on the signal strength meter. Is it
>> possible I am hearing this signal from the bird or could it be a
>> local source? I already have 4 versions of the Raspberry Pi but
>> figured this would be a reason to purchase the version 3! We all need
>> a good excuse to present to the XYL.
> Hi Rick,
> The signal you describe doesn't seem to me like Outernet's signal.
> Outernet's signal is a bit more than 4kHz wide and it doesn't have any
> breaks in it.
> -60dBm on your SDR software doesn't really mean anything unless you have
> calibrated your signal meter (and -60dBm would be way too high for
> Outernet's signal). What is strength of the noise floor?
> Some 10's of kHz above Outernet you have 2 other signals from the same
> Inmarsat satellite. They are a bit narrower than Outernet and much more
> stronger (perhaps 10dB even). I would use those to check if you hear the
> bird.
> I haven't run the numbers, but I wouldn't expect that you'll be able to
> hear Outernet with a discone and no LNA. In my experience the FUNcube
> Dongle Pro+ is not very good at 1.5GHz (but I haven't done any serious
> tests), and if you have a long cable run from the antenna to the dongle,
> then you definitely need an LNA.
> By the way, Outernet's software doesn't support the FUNcube dongle, only
> the RTL-SDR or MiriSDR. You may want to look at
> https://github.com/daniestevez/gr-outernet
> which supports any SDR that works in GNUradio.
>> Finally, I keep thinking if I get all the components to grab this
>> data, is it really worth it other than to say I did it? Thanks for
>> any guidance or comments. Rick - WB3CSY
> That's something you'll have to decide for yourself. What you currently
> get is:
> * An hourly small file with a listing of all APRS packets sent through
> satellites or the ISS and all APRS packets containing the word OUTNET.
> * Some grib files with the weather (most useful to sailors)
> * Some other weather data
> * Random (most popular) wikipedia pages
> Most of the bandwidth is spent with wikipedia pages, and the bandwidth
> is not so high: you can only get about 15MB worth of files per day.
> Of course you could get the same content on the internet.
> If you just want to see how it looks like, I have several brief SDR
> recordings and recordings of Outernet frames that can be used with
> https://github.com/daniestevez/free-outernet/
> One reason to get the hardware for Outernet (LNA and perhaps patch
> antenna) is that it can be used used not only to receive Outernet but
> many other things on the L-band.
> 73,
> Dani EA4GPZ.
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