Should I bother transporting a sattelite dish at the countryside? - Page 1
Forum section: electronics / rf-microwave

author: RoGeorge
author_rank: Super Contributor
timestamp: October 19, 2018, 02:52:51 pm
content: I found 2 satellite dishes dismantled in order to be thrown away. I guess they were from former satellite TV receivers (now the building has fiber optic and IPTV).- one smaller, metallic, about 70cm (23inch) diameter, the white paint looks like new, with an eccentric LNB arm- one bigger, about 2 meters (6 feet) diameter, made out of some semi-flexible material that looks a translucent fiber glass, with the reflective paint almost completely goneAlready harvested the 2 LNB's, mostly out of the curiosity to open them later, secretly hoping for some RF goodies inside, but didn't open them yet.I am not a ham, so I am thinking more about reusing them for capturing weather pics with an SDR, maybe some day RF astronomy scans, or a huge solar furnace with the big one.1. Does it worth to collect the dishes for some other projects?2. Is it reasonably possible to transport the big one tied on top of a normal sedan car about 100Km (60 miles) away?3. Other ideas for interesting project to do with them, please?

author: TheBay
author_rank: Unknown
timestamp: October 19, 2018, 10:57:20 pm
content: The larger 2m one is likely to contain mesh, not a reflective coating, would be interesting to see pictures of it.Lots of uses for dishes, I have 2 Large motorised dishes I play with.But I use them for satellite use, there are 100s of satellites up there on all different bands.

author: coppercone2
author_rank: Super Contributor
timestamp: October 19, 2018, 11:24:53 pm
content: is there a big difference between low end satellite dishes and high end ones? Is the geometry, reflectivity, durability of a TV sat antenna dish similar to something meant for scientific use?

author: rhb
author_rank: Super Contributor
timestamp: November 22, 2018, 10:54:16 pm
content: If you were closer to central Arkansas I'd offer to relieve of the mental strain of deciding.I think a rental truck or a trailer would be more suitable than the roof of the car for the big one.

author: cdev
author_rank: Super Contributor
timestamp: November 23, 2018, 12:36:39 am
content: If you have a means of testing them for perfect focus, do so.They should be able to focus sunlight to a tiny point. (wear eye protection while testing this!)A tiny deformation in a paraboloid structure may be almost invisible but make a dish useless for moonbounce, etc.

author: rhb
author_rank: Super Contributor
timestamp: November 23, 2018, 01:04:31 am
content: The accuracy required is a function of the wavelength. Astronomical parabolic mirror accuracies are commonly 1/8th wavelength. For C band, which is what the large dish almost certainly is, this is 5-10 mm. So testing it and correcting any errors is not especially difficult. Optical tests are not needed.Although I live in town, it's a rural area. I see old, unused C band dishes fairly often. You've made me realize I need to go see if I can get one cheaply.

author: RoGeorge
author_rank: Super Contributor
timestamp: November 23, 2018, 06:40:05 am
content: Once I covered the interior of a smaller one (about 1 meter diameter) with Aluminium wrapping foil nicely stretched and glued. It was good enough to make a spot in the sunlight, but not focused at wall. The spot was about the size of football ball, with unregulated shape. The geometry of the dish was lousy. At most, it could have been used to heat a sterling engine placed in the focus point, but it was too small to get any significant power out of it. Maybe the big one would have worth, but keeping the monster dish oriented to the sun would have been too complicated.Anyway, the two dishes from the beginning of this thread are long gone now.

author: Messtechniker
author_rank: Frequent Contributor
timestamp: November 23, 2018, 06:49:55 am
content: For long distance audio recording fit a microphone at the focal point.Then you are in for some interesting results.

author: coppercone2
author_rank: Super Contributor
timestamp: November 23, 2018, 05:39:26 pm
content: The idea about optical focal point is perfect.

author: cdev
author_rank: Super Contributor
timestamp: November 23, 2018, 07:00:13 pm
content: Ask hams. I suspect that it varies a lot by how they are constructed.A dish thats not true wont focus. Its like astigmatism.Quote from: coppercone2 on October 19, 2018, 11:24:53 pm