Wxtoimg image shifting software#

After reviewing my recordings and looking at the settings, I relized gow stupid I was, I failed to turn up the gain on the receiver, so the only thing I was reviving was noise.ДЄfter some face-palming and hating myself for being so stupid, I decided to have a second try. ItвЂ™s not that the signal was faint, I had noise or the hardware just didnвЂ™t want to work, I just could not see any signal at all, apart for a random burst of data every here and there at 139ish Mhz. So there I was, in the freezing cold winds holding up an antenna trying to receive the signalвЂ¦ and I failed. Assuming I am getting away from any unwanted noise sources, unwanted transmissions and any reflections from nearby objects such as buildings. The first time I tried, I took at my gear and headed of to a good, open and quiet area. ItвЂ™s a signal! From space!ДЄt total, I had tried 3 different attempts at receiving the signal. The answer to that is that I as IвЂ™m using a Linux system to receiver the signal, I could not be bothered in setting up the audio piping needed. If you have either read up or received a APT signal before, you may be asking why I did not setup WXtoImg or anything similar. I decided to only try to receive the signal when the satellite was crossing overhead at a high elevation, this was good as it reduced the number of parameters for me to debug when it all went wrong. In Gqrx I tuned the main frequency to 137.1MHz (NOAA-19) I also had to set the gain to maximum, modulation to narrow FM and a filter width of approximately 45kHz. The final (working) setup consisted of a dipole antenna with the two sections measured out to approximately 54cm (1/4 wavelength of 137MHz) connected to a SDR dongle feeding into a a laptop running Gqrx SDR. I also set up OBS to record my display so I could benefit from some hindsight later when I analyze any mistakes I made.

Wxtoimg image shifting software#

On the software side of things, I used two main pieces of software, first was Gqrx SDR as the receiver frontend, and Gpredict to track the movement of the satellites, pass times and pass details. Most resources state that a QFH antenna is needed, but for a proof of concept only a simple dipole can be used, so I decided to go with the dipole as itвЂ™s the simplest antenna to find or construct. Next I had to decide on an antenna, there is no shortage in antenna types and designs. This is excellent as I already have 2 receiving SDR dongles that go up to 1.7GHz and access to a few more SDR platforms that can got from 70MHz to 6GHz. The first thing I had to do was to record a signal, by looking at different resources such as Wikipedia, Datasheets and other online resources I found that the signal is transmitted at the 137MHz frequency (with some shift depending on the actual satellite passing).

Therefore before the satellites degrade to a point theвЂ™ll be retired, I want to receive, record, explore and decode an APT

NOAA-19 - Launch February 6th 2009, (Designated NOAA-NвЂ™).ДЄs the dates suggest the newest satellite is already 11 years old, and the oldest is about 22 years old.

NOAA-18 - Launch May 20th 2005, (Designated NOAA-N).

NOAA-15 - Launch May 13th 1998, (Designated NOAA-K).Currently, there are only 3 active satellites broadcasting APT signals, each satellite designed to last at least 2 years: On the 6th February 2009 NOAA-19 was launched and is the last satellite to use the APT system. Unfortunately as this very old tech (over half a century), this system is now being phased out and giving way to a more sophisticated and advanced digital transmission system. The first satellite to have this system put on board was TIROS-8 which was launched at the 21st of December 1963 and lasted 3 1/2 years in operation until July 1st 1967. So what is APT? Short for Automatic Picture Transmission itвЂ™s a protocol that was designed in the early 1960s to (you guessed itвЂ¦) transmit real time images to earth from space. For a few years now, I have been aware of meteorological satellites using the APT system (mostly US NOAA satellites) that transmit many types of information. Unfortunate as much as GPS is an intriguing and marvelous system itвЂ™s a very simple signal that does not very interesting data. Now, I know that my phone can pickup signals from space, and I use it every dayвЂ¦ itвЂ™s called GPS. In the past few years I have wanted to explore the world of different signals from space.