Friday, 24 May 2013

Radio Astronomy Station. Part 2.

Radio Telescope Diagram.

The Radio Telescope consists of a Raspberry Pi computer and DVB TV receiver USB stick mounted in a box at the focal point of the Dish. The Raspberry Pi also communicates with an Arduino Uno mounted in a control box under the Dish to control the azimuth and elevation.

An ethernet cable and power cable run from the Dish back to the control room.
In the control room the main system PC has the Radio Eyes Telescope Control Program, SDR Radio Client and Skypipe digital chart recorder.

A remote operator runs the Radio Eyes program which allows the management of where and when the Dish should be active. The commands for pointing the Dish are then sent to the Telescope Control Program as a 'Task' for later activation.

The receiver connected to the Raspberry Pi can be commanded by the SDR Radio Client to monitor a particular frequency and the signal comes out of the PC audio out socket for monitoring through a local speaker. This audio is fed back into the PC for recording by the Skypipe software and plots the intensity of the received signal.

A remote operator can also log in and see a waterfall display of Frequency/Time/Intensity covering several Megahertz bandwidth.

SDR Receiver

This is the DVB TV receiver I bought on Ebay for less than $20.
Fortunately it has the correct RTL2832 and E4000 devices. Obviously the nifty little infra-red remote control isn't going to be of much use. It also came with a little antenna and magnetic base with cable and plug, also not a lot of use.

Raspberry Pi

The Raspberry Pi is now available in sufficient supply for them to be readily accessible through your local supplier. I bought two in November 2012 and they arrived just before Christmas. Perfect timing for the Holiday break.
I'd recommend getting hold of a Pi and the DVB receiver and getting these two devices working together. My previous post has a link to Peter Goodhalls web page with instructions for getting the Pi talking to the receiver.
You should then be able to remotely log in to your Pi and receive audio and control the Frequency and mode of reception.
I used my Android phone with an app called SDR Touch. This allows entry of the IP address of the Raspberry Pi so you can connect and receive audio.

In the next post I will show some results of the receiver and SDR client software and what we can do with our system so far.