3m Diameter Portable Total Power Reciever

[Marijn]

Haha nice title right, a 3m PTPR:D

It comes down to the fact that I am in the process of completing another idea of mine which is completely running out of hand.

A while ago I completed my 8"Dobson, and suddenly had the crazy idea that I could also adopt this mount to.. a radio telescope. I live in a rather light polluted area, but built my dobson for deep sky.. so logically I wondered if I couldn't make better observations by recieving different wavelengths than optical wavelengths. I didn't have any idea on the operating principles of these scopes, but it surely drew my attention! After some initial reading I realised that Radio telescopes are actually véry simple, and buildign onme shouldn't be too hard. My first ideas on paper:

It looks simple! A dobson style mount, the dish is like a large umbrella.. a Cantenna as recieving antenna, small tripod under the mount. After spending more time on the internet, I went on to make better conclusions on what I was going to build and what it was supposed to do. Also I visited the Synthese telescope at Westerbork..

After this I was sure that I wanted to build a dish, 3m wide. It was going to have a Cantenna as reciever, designed to recieve 1420Mhz (Hydrogen line). The electronics were going to be simple, 1 LNA & an Inline amplifier, no filters, so technically it's a Total Power reciever with an antenna most suited to 1.4Ghz.

The mount wasn't going to be Dobsonian, but Equatorial. Many many drawings followed.. but in the end I just chose the German Equatorial mount for it's flexibility and simple contruction. Materials: Mostly playwood, some alum., Skateboard roller bearings, PVC shafts, alot of glue and screws. Simple, cheap & robust.

The dish was going to be made of Alum. spars, carefully bend into the corresponding parabolic shape. The dish was going to be covered with some type of metallic grid.. however the only grid I ever managed to find which was flexible enough to be folded without permanent deformation, costed more than 12euros / square meter.. a little bit too much for a simple experiment. Eventually I chose Isolation underfloors, which consists of a sort of thin plastic foam with a alum/mylar covering. The whole dish is rivitted together.

Offcourse there's much more to be told, but I think photos tell the whole story quite well. I made a lot of adjustments to the mount because it wasn't holding up to the weight. Currently the project is nearing initial completion, after which I will finish it in a nice white gloss. Currently it still needs electronics/wiring & motor drive.

Best regards to all, I hope you enjoyed

Marijn

[Marijn]

Marijn

[Demonperformer]

Fantastic project. It will be very interesting to hear what sort of result you get.

[Catanonia]

Always wondered if this was possible with the amateur. Watching this with great interest and can't wait to see what you will get. Will you get actual pictures from this setup?