Tag Archives: Software Defined Radio

Some LNA tests for HRIT/LRIT

So I was talking with @luigi on OSP RocketChat and he noticed that one of the LNA’s I suggested alogn with the LNA4ALL (the SPF5189) got a comment on ebay saying that it doesn’t work on L Band.

So that was weird to me, since I have 5 of them, and one currently in use with my GOES setup. So I decided to do a small and crude benchmark for L Band comparing no LNA with LNA4ALL and SPF5189.

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GOES 16 Test Week Results

In the week from March 27th to 31 NOAA performed some new downstream tests over HRIT link on GOES-16. The idea was to transfer some CMI (Cloud and Moisture Imaging) products and see if the software developers and current stations could receive it fine. Before starting talking about that, please notice that all data sent so far is stated as test data and should not be used for any real world measurements. As NOAA states (and I forwarded on my last post):

The user of that link assumes all risks related to the use of their data and NOAA disclaims and any and all warranties, whether express or implied, including (without limitation) any implied warranties of merchantability or fitness for a particular purpose.

So I kept my dish pointed to GOES-16 all over the week and did record the Monday testing (that contained CMI images) and recorded all files sent all over the week. Some of them are automatically posted on Twitter / Instagram by my OSP Bot but not all of them. I had discovered some issues with my Virtual Channel Ingestor on GOES Dump, and also most of the new data was not being handled correctly by Goes Dump. Working together with @usa_satcom we managed to almost zero-out the bugs in GOES Dump.

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137MHz Bandpass filter for NOAA / Meteor Satellites

Yesterday I saw a new blog post by Adam (9a4qv) in LNA4ALL. The post (here) talks about a band pass filter he did for Weather Satellites and I decided to try as well.

Unfortunately I don’t have a exact match for that components at home, so I tried to do something with the components I have. So the lower value I had for capacitors was 10pF, and the needed values for Adam’s Filter is 1pF, 4.7pF and 15pF. I decided then to use 10 in series to do the 1pF, 2 in series for the 4.7pF (that will be 5pF) and then one in parallel with two in series to give me the 15pF. Its a very close match, and I’m unsure about the effects of serialization of capacitores in the filter (increase inductance maybe?). So here is the results.

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20160119_191023

So I few weeks ago I received a LeMaker Guitar board that I won on a contest. I got really happy about that and they sent by DHL that made everything went really fast.

As usual, in Brazil the tax everything including prizes and samples, so I got R$90 of taxes over the board. I won’t complain much about it, because it was cheap and expected.

So after some time (sorry for the long time, I got really busy 🙁 ) I managed to write this review about this board!

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Play with SDR and Intel Edison!

So some people already saw in my facebook that I started playing with SDRs (Software Defined Radio).

I always wanted to do my own radio receiver, and I did some in the past. But it’s very hard to adapt the radio for anything new you want do to, and also when you want to process data in your computer things become harder.

So a few months ago I found a nice tutorial of how to get NOAA Satellite Images using a cheap DVB-T (Digital Video Broadcast – Terrestrial) dongle that can be used as SDR. It costs about R$70 (roughly US$10) and the model I got (with R820T2 tuner) can tune from 24MHz to 1.74GHz!!!

What is inside this spectrum?

Actually a lot:

  • FM Audio Radio Broadcasts
  • VHF / UHF Television (Both Digital and Analog)
  • Weather Satellites (APT, LRPT, HRPT)
  • ADB-S (Air Traffic Telemetry)
  • FM Air Traffic Radio
  • And more

So my goal was to receive NOAA APT Signals (I even made a decoder!) but I don’t have a good enough antenna (yet).

The problem

So I made up a piece of antenna with two copper pipes (I call a piece, because its a dipole from a Double Cross Antenna) (I will make a tutorial later how to do it) to have better reception for the 2m band (~135Mhz) but every time a satellite was in range, I would need to go outdoor and turn on my laptop and start capturing. This was annoying.

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