[HN Gopher] Guide to Doing Radio Astronomy with RPi and SDR [pdf]
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Guide to Doing Radio Astronomy with RPi and SDR [pdf]
Author : ChuckMcM
Score : 102 points
Date : 2022-01-03 21:32 UTC (1 days ago)
(HTM) web link (drive.google.com)
(TXT) w3m dump (drive.google.com)
| tverr_bjelke wrote:
| Great project! I am surprised to see the actual "telescope" being
| a metal pipe with a small funnel - there is no satelite-DISH-
| reciever-thing ! I have to dig deeper... one day...
|
| Btw I was hesitating to fetch the pdf, because I had to allow
| javascript for both google and gstatic on my computer, which I
| normally would not do. Why is it, that following a link to a
| google drive file needs this local execution of code stuff
| instead of simply delivering the file? For public openly
| accessible stuff this feels very weird to me ( comparing to
| simple (s)ftp file fetching)
| TacoSteemers wrote:
| This is off-topic and not a criticism, my apologies if it is not
| well received. I am not sure if I worded this correctly.
|
| It helps to have some kind of introduction if we want to share
| our work with a wider audience. For this kind of topic I think
| that the people who already know what radio telescopes and radio
| astronomy are would be able to find this kind of information
| elsewhere if they wanted, but people like me who don't are
| "scared away" by the information because there is no introduction
| to the topic.
| pastage wrote:
| >The goal of this project is to enable everyone to discover
| that our Milky Way Galaxy surrounds us
|
| The quote is from the purpose on the first page. All of it
| really is at a DIY level were you get enough information to
| actually do something, but you will still hit snags. So you
| might be right that it is not aimed people who do not know the
| basics. I do not see the weakness in the writing so maybe you
| could explain what you would need?
| wdfx wrote:
| I can chime in regarding some weaknesses of the linked
| document.
|
| I approach this as a highly technical person, programmer,
| electronics tinkerer, and someone who has been actively
| exploring SDR for over a year now, with RPis and a few
| different SDR hardware and software types.
|
| I've become quite familiar with how "terrestrial" radio works
| from this period of experimentation, and I think most people
| who have ever used any form of analogue radio would not have
| much issue figuring out what's going on just by playing with
| an SDR and a length of wire as an antenna.
|
| I opened this document expecting some introduction as to how
| I might get started with radio astronomy. After reading the
| whole thing through, I'm left rather in the dark about what
| results I would be seeing if I were to go to the trouble of
| following the instructions and getting it running;
|
| - the document in parts seems to be a bit back to front. some
| of the concepts are explained _after_ the instructions to
| implement them
|
| - it's full of technical jargon which is not explained at all
|
| - it doesn't explain how to interpret any of the captured
| data beyond "this small bump represents the milky way" - what
| else, for example could be observed with this equipment, and
| how does that differ from what's shown?
|
| - it offers no help as to how to figure out what's going on
| if your results don't match what's shown in the document
|
| - it offers no indication of where to go after carrying out
| just the one observation shown
|
| - there's clearly some text missing in the part about the
| analyse scripts and what they are supposed to do
|
| I could go on, but the above would be my main gripes with it;
| the result of which has left me with a feeling that this has
| taught me nothing about radio astronomy and no desire to
| build the antenna or use the software.
|
| EDIT: formatting
| wdfx wrote:
| Following a bit of a trail from a link in the doc I've
| found a whole bunch of related technical docs:
|
| - https://github.com/WVURAIL/lightwork
| tkinom wrote:
| Name the project "SETI@PI"?
| jalino23 wrote:
| I recently just discovered how radio is everywhere in our lives
| and I wanted to experiment and learn it. but as I dove deeper I
| learned that its illegal to emit your own radiowave. so I gave up
| cause I'm scared to do something illegal unknowingly but it succs
| because I really wanted to learn how nasa talks to mars rovers
| with radio by getting by getting my hands dirty.
| ChuckMcM wrote:
| I encourage you to learn more. There are frequencies where
| anyone can transmit small amounts of power (they are the
| unlicensed bands) and they are available in every country. Many
| countries also have an amateur radio organization which are
| people like you who are interested in radio and want to learn
| more. Opportunities are available to use your radio to assist
| in disasters and other emergency situations, and of course it
| can lead to a career in working with a commercial broadcasting
| company.
| madengr wrote:
| Just get an amateur radio license and there are plenty of bands
| to legally transmit.
| pastage wrote:
| Get into amateur radio, then get a license basically you just
| need to know what the limits are.
|
| https://en.wikipedia.org/wiki/Amateur_radio
| tejtm wrote:
| Fear be gone!
|
| I took the plunge got the license started learning radio. turns
| out everything I have wanted to do so far which is listen and
| learn I never needed the license for in the first place.
|
| The amateur license is to transmit.
|
| You can receive anything anytime anywhere in fact you are
| anyway since we are continually bathed in an electromagnetic
| soup you may as well decode bits of it.
|
| Software Defined Radio (SDR) dramatically lowers the barrier to
| seeing chunky bits in this electromagnetic soup.
|
| I first got a rtl-sdr (usb dongle) for under $10.
|
| Now I am having a blast building Quadrifilar Helical Antennas
| from plumbing supplies to get the pictures NOAA satellites are
| sending when they are over head. (no license needed)
|
| I encourage anyone with even a passing interest to to consider
| starting with "read only" and not even worry about talking the
| transmitting tests till you figure out if that what you want.
| ChuckMcM wrote:
| Software defined radio is a lot of fun for me, there is
| interesting math, there are weird RF signals to investigate, and
| it is fun to decode things like ADSB flight data. That said, if
| you want to do real science, you can also do radio astronomy with
| these things. For a relatively small amount of money ($300 - $500
| US) you can set up a radio telescope in your back yard that
| doesn't suffer from a lack of "dark sky". Also makes for a great
| science project!
| bmitc wrote:
| Do you have any particular references for backyard radio
| astronomy? I have been thinking about a visible light
| observatory, but those have a lot of constraints. So I was
| curious what could be done with a backyard SDR setup.
| neapolisbeach wrote:
| I've had a lot of fun doing Hydrogen line backyard astronomy.
| I wrote up an article on my experience [1]. These are two
| great sites as well [2][3].
|
| [1]https://hmcguinn.com/posts/hydrogen-line/
| [2]https://www.rtl-sdr.com/cheap-and-easy-hydrogen-line-
| radio-a... [3]https://physicsopenlab.org/2020/09/08/milky-
| way-structure-de...
| elkos wrote:
| And they can help us out witn SatNOGS (https://satnogs.org) as
| soon as they finish this up now that they are familiar with
| Raspberry Pi and SDRs ;)
| wrycoder wrote:
| That's interesting, but, given the network, what do you do
| with it?
| jcims wrote:
| Very nice writeup! Getting into SDR is an eye opening experience.
| A little stub of conducting wire lets you tap into a dimension
| that is completely invisible to our senses. It's almost like
| hearing there are billions of neutrinos passing through your
| thumbnail every second, except there are people and machines on
| the other end.
|
| There's a huge list of things you can do with the RTL-based SDRs
| in the article. Expanding to more capable hardware generally
| improves the quality of the data and enables higher bandwidth use
| cases that are difficult to pull off with cheaper radios, but for
| $30 you can get into all sorts of interesting stuff. (Turns out
| making your own antennas is half the fun)
|
| If you want to just poke about you can access SDRs online through
| web-based consoles like websdr.org and kiwisdr.com (mostly
| shortwave and ham bands, the latter has a cool trilateration
| feature) or some of the major SDR software products (like SDR-
| Console and SDRSharp) have their own volunteer network of radios
| you can tune into (with caveats and limits of course) with their
| software.
| nickcw wrote:
| What a fun project. I love SDR.
|
| Could you upgrade that to make a 2D picture? Would you need
| motors to step it around the sky?
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(page generated 2022-01-04 23:01 UTC)