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.
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.
So it has been a time since my last post (again). Today I’m writting about a TV/FM Diplexer that I bought to address a issue that I’m having here with my NOAA stuff.
So the biggest problem is that in São Paulo the FM Radio (88-110MHz) are VERY strong. I can receive a -40dBm signal with a RTL-SDR with no gains in almost all channels. This is a big issue since the RTL-SDR does not have a input filter (actually it has, see my patches at https://github.com/librtlsdr/librtlsdr ) the LNA gets very easily saturated when getting gains over 25dB (usually needed by APT Signals). So I start to search for a FM Band Stop Filter. But it turned that it was not so simple to do a good FM Band Stop Filter.
So I started searching for a commercial filter, and I noticed that most of the FM Filters were discontinued a few years ago and the only thing I could find was a FM/TV Diplexer.
So in my last post I was playing with my RTL-SDR with an Intel Edison. So I decided to build a QFH Antenna to ble able to receive NOAA APT Signals. These NOAA Weather Satellites broadcast a APT signal with about 5 to 8 Watts at 2m band, and considering how low this power is, it might suprise you that these signals arrive pretty strong at earth surface. But the biggest challenge to receive this signals are not its power. Its all about movement.