Question on satalite dishes? - Page 1
Forum section: electronics / beginners

author: Shadetreeprops
author_rank: Regular Contributor
timestamp: March 18, 2016, 12:05:00 am
content: I have a few dishes, one is the old 5 LNB DTV dish, another is one that i pulled off the military base i work at, but it dose not say what it was for. It has a single end.other than that i have a dish network dish.Is there anyway that i could possibly convert them to send Radio signals, or intercept communications..its something i have had interest in doing for a while. But i could not find anything on youtube.Other than using one to get long distance WiFi which i did and was fun, but required no real skill to do. Was getting signals from 10 miles away at 4 bars at my house. And about 1000+ networks, at least 45% of them were not secure.but that is what sparked me to think..is there a way i could listen to space, or signals bouncing about? With three of them i could almost get a full 360 degree radius. Stupid dish network dish had to be a old round and not oval.i have been thinking about singling out signals, buy being about to turn off dishes to listen to stronger signals, as well as see what dish was getting the best signal, possibly puting some motors on them so i can focus them to certain areas..adjusting the pitch and yaw.It was just a thought, and probally right now out of my league of understanding.

author: German_EE
author_rank: Super Contributor
timestamp: March 18, 2016, 09:48:59 am
content: OK, lots of questions and I will try to tackle them one by one:Is there anyway that i could possibly convert them to send Radio signals, or intercept communications?If you want to transmit then you need a ham radio licence and even then you can only transmit in specific bands. Stray outside of these bands and the FCC will come knocking at your door. If by "intercept" you mean listen in on other communications then yes, it is possible, you just need a low noise block for the band that you are interested in and a multi-mode communications receiver that can work at the LNB IF frequency.Is there a way i could listen to space, or signals bouncing about?Tune an analog TV between channels on UHF, about 0.1% of the noise you see is from the Big Bang. Radio astronomers listen on specific frequencies (someone help me out here) but unless you want to use a really big dish and some very expensive low noise amplifiers you won't pick up pulsars or other stellar signals.With three of them i could almost get a full 360 degree radiusThat would be 180 degrees as the rest will be masked by the mass of the Earth. Dishes have a very narrow bandwidth and will need to be steered, then you will need to work out how to accurately and repeatedly point the dish at what you want, this is not easy. Dish shape does not matter, round or oval both work.i have been thinking about singling out signals, by being about to turn off dishes to listen to stronger signals, as well as see what dish was getting the best signal, possibly putting some motors on them so i can focus them to certain areas..adjusting the pitch and yaw.Any dish has three adjustments and all of them are critical. 1) Rotation, set with a compass, which direction are you pointing? 2) Azimuth, what angle is your dish at, set using a spirit level and referenced to horizontal ground level. 3) Skew or polarization, altered by rotating the low noise block in the clamp for fine adjustments and switched between horizontal and vertical polarization by a satellite receiver.Short answer, go find a friendly satellite dish installer and buy him a few beers.

author: VK5RC
author_rank: Unknown
timestamp: March 18, 2016, 10:35:06 am
content: If you are really serious re space etc, there are several amateur radio satellites that can be listened to relatively easily, an antenna such as a yagi or if really keen a high gain antenna such as a dish (remember in antennas gain comes from the narrow 'view' angle) you could easily pick some of the communications from these satellites and if you work hard you can listen to the space station.As most of theses are not in a geostationary orbit, you need the ability to steer the dish, fortunately a lot of nice Hams have down the work before and have shared it on the net, it does take quite a bit of effort to do it cheaply e.g. rotary encoders and serious PIC programming e.g.http://www.vk5dj.com/satellite.htmlor if there is a bit of spare cash it can be bought relatively off the shelf, see AMSATs storehttp://www.amsat.orgAMSAT is e pretty good resourceThere are also a lot of guys using Software Defined Radio 'dongles' , a google of SDR dongle and satellite bring lots of interesting stuff. One reasonably well organised area is the 'fun-cube dongle' guys. A data transmitting low earth orbit satellite, can be picked up with no steering PC etc and a reasonable antenna, I think the fun cube satellite is still up (they don't last forever!)As a Ham, with a reasonable job, I went down the path of using a pre made Azimuth and Elevation rotator (Yaesu G5500) with one of AMSATs PC to rotator interfaces and using their PC software to control both the antenna position but also the doppler shift on my radio , an Icom 910 ( a satellite coming at you, transmitting at 400MHz has about 5-10kHz of shift) . Satelites often operate 'split', i.e. transmitting on one freq e.g. 148MHz, receiving on another e.g. 440MHz.A good program can also 'adjust' the receive and transmit frequencies as the satellite passes overhead.You can do it a LOT cheaper but a bit more metal bending is required but it is not impossible and there are a LOT of Ham guys who have done it and have posted there success on the net.If you are all inclined, getting your Ham licence can then allow you to transmit, well legally anyway, and there are a lot of other areas of RF experimentation that you can get your teeth into once you get your 'ticket'. The American amateur radio society, the ARRL has a lot of info.I have had several conversations via amateur radio satellites, from Adelaide in Southern Australia to other parts of Australia and Indonesia.Hope this is of help.Rob

author: Shadetreeprops
author_rank: Regular Contributor
timestamp: March 19, 2016, 01:13:49 pm
content: now that i got a chance to go over this basic list of things. I need to note it all down. so i can work on this as i go. No delusions of having this done in a week, but a good starting point.I am glad to know i can use my dishes for this. I heard that i needed a licence, but i do not think i will need one just for listening. kinda like a scanner. now to figure out of i can modify one of my spare recivers to recive radio signals instead of the tv signals it decodes. If nothing else i can go to the swap meets for military stuff, and see what they have.I know i sold a bunch of military raido anttenas at a swap meet once faster than anything. so they should have some stuff i am looking for on the cheap.

author: w3amd
author_rank: Regular Contributor
timestamp: March 19, 2016, 11:37:57 pm
content: Quote from: Shadetreeprops on March 18, 2016, 12:05:00 amFor the dish and signal strength you'd be best off with one single dish pointing in the correct direction. Phasing dishes is much more complex but done for antenna arrays for space. Many places in the world are working on this. Listening to space might get you Hubbell images and other things around. You'd likely be working against encryption not in your favor.As stated though, Amateur radio license in the US will give you the ability to transmit over microwaves with quite a good amount of power AND enormous frequency ranges.http://www.arrl.org/files/file/Regulatory/Band%20Chart/Hambands_bw.pdfCheers,John

author: German_EE
author_rank: Super Contributor
timestamp: March 20, 2016, 10:02:58 am
content: If you want to see images from the Hubble Space Telescope looking at the raw data is the wrong way to do it, for starters it will be in black and white! The following web pages will give you lots of images:http://hubblesite.org/gallery/http://www.nasa.gov/mission_pages/hubble/multimedia/https://www.spacetelescope.org/images/http://hubblesource.stsci.edu/sources/illustrations/WARNING VERY LARGE FILES