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Trying to build 1.8 Meter radio telescope


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I have been interested in radio astronomy for a long time due to the climate where I am. It is cloudy most of the time and a nice clear night is a rarity, and even then light pollution can get in the way of truly spectacular results from my optical telescopes.

I have a 1.8 meter satellite dish, specifically a General Dynamics series 1184 dish without any of the supporting brackets, mount, or electronics. I was able to track down some very thorough documentation on this reflector and it appears to be able to operate in the Ku band from 10.95-12.75 GHz as well as the C band from 3.625-4.2 GHz. It is also receive/transmit. It has been sitting outside for a while but I have reason to believe it is in good condition, and the documentation says it is virtually impervious to the environment because it is made of pretty beefy fiberglass.

http://www.satelliteguys.us/xen/attachments/1184-rxtx-pdf.57878/

I want to turn this into a radio telescope, hopefully something that can observe radio sources other than the sun. How should I get started on this?

Fabricating new brackets for an LNB would be easy, but im not sure what sort of LNB I should get or how to connect one to a computer. I also have some ideas for a mount which would allow it to track objects, but for now its going to be on a stationary mount which I will make.

 

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That was a very helpful resource, thanks.

So I think what I might do is I will build a cylindrical waveguide feed for 1420 MHz, then pipe that into an SDR module. Would an amplifier be required between the SDR and feed for this to work or would that just be a better setup? I know that in most cases a radio signal is weak and requires an amplifier of some sort, but this dish does have a pretty high gain.

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Ok read some more, and now I think I have a pretty good plan. Im going to get a fairly cheap low noise amplifier and software defined radio module, and then fabricate the bracket for the cylindrical feed which I will also make.

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  • 4 weeks later...

Hi not sure how far on you are on this but here's some bits I learned. One of the most helpful sites is SETI and their associated sites. They have a huge amount of detail on the hardware for building a radio scope in the hydrogen line 1420 MHz.

I had experimented with a huge yagi type antenna along with a high gain 1420 MHz amplifier and filter from radio astronomy supplies in USA. I had limited success but was able to detect the milkyway.

The feed horn for the dish you can easily make and there is an easy formula for working out the correct position on the dish focus point you can use satellite inline amplifiers to minimise loss in the coax cable they are very cheap.

The most important item you will need is a low noise down converter. It is the heart of the system as far as I'm concerned. It converts the 1420 MHz signal to around 30 MHz which most radio receivers can be tuned. As well as doing this it amplifies the weak signal your wanting by a huge amount. Exactly the same as a satellite lnb for Sky TV does but at different frequencies but same principle.

Your aim is to get the maximum gain and lowest noise figure out of your system.

It can be a challenge but a great project for day and night. I'm no expert just tinkered at it for a while.

Good luck

Carl

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