Receiving Earth Photos From Satellite With TV Tuner

Introduction

There are a lot of satellites above our heads. Did you know, that using only Your computer, TV Tuner and simple DIY antenna, you could receive the transmissions from them? For example real time pictures of earth. I'll show you how.

You will need:

• 2 wires (could be from ordinary electrical cable)

• some plywood or wood for an antena

• coaxial cable (TV cable)

• some plywood or wood for an antenna

NOAA satellites

I decided to first pick the signal from NOAA satellites. The NOA satellites are over 800 km above earth and they are flying around the world in just 100minutes. During this flight they are taking the photos of earth and those imgase are then trasmitted via 137Mhz FM frequency to earth.

To recieve the satellite transmission You will need an antena. The easiest one is just two 53 cm long copper wires connected in V shape under 120 degrees. Such antena is made for a 137Mhz frequencies.

Antenna

I made antenna from plywood as the holder and from ordinary electric copper wires. Those wires are then connected to the TV coaxial cable and that's all. Nothing more is needed. The whole antenna took me no more than 20 minutes to built.

Receiver

For reciever we can use TV Tuner based on the RTL2832U chipset. Such device cost about 10 USD, so it is very cheap and it allows You to watch the TV on Your laptop.

The tuner is in fact SDR device - Software Defined Radio - it means that it could recieve the FM frequencies and could be controlled with the computer software and that's all we need.

After installing the Tuner on Windows, You have to 'hack' it by replacing the original drivers by Zadig software. Run it and click replace the drivers.

On Linux, the procedure is different and could be found under this link:

Software

Now the software to track and predict when satellite will be over your area. I recommend to use WXTOIMG because this is super easy program, available for all systems and it also decodes the signal from satellite.

To predict the NOAA satellites, you have to set your ground station in the options for your location. Then select the Satellite Pass List option and you will see when and on what frequencies you have to listen for the signal.

You will need another program, to control Your TV Tuner, receive and record the signal from the satellite.

For Windows I recommend SDR Sharp, for Linux/Mac You can use GQRX. Both software work in the same manner.

You select the frequency, on what you want to listen and you will not only hear the signal but you can see it on the diagrams in the SDR software.

Now we have all we need. So when the satellite is above us, open the SDR software, set the frequency for 137,XXX MHz and set the reciver options like this:

• modulation FM

• band: 44khz \

And push the record button when the signals will start appearing.

After you recorded the signal, you have to change it's frequency from 44khz to 11025 Hz. I used the Audacity software for that. Just open the .wav file, change the frequency and write it once again.

Last step

The last step is to open the WAV in WXTOIMG. After this the program will automatically decode the signal and.. that's all! You have Your pictures of earth.

You can select different types of decoding in Wxtoimg like temperature, continents, seas etc.