Dutch radio amateurs image far side of the Moon using Chinese satellite data • Hacker News Board

Re: Dutch radio amateurs image far side of the Moon using Chinese satellite data

#41

Post by mimiflynn » Wed, Feb 06, 2019, 2:00 PM UTC

DerekRobot wrote: post #39

mimiflynn wrote: post #35

Earlier quoted context omitted.

To experiment in radio on certain frequencies (like the ones needed to talk to satellites, requires a license from your nation's government, as radio frequencies are a shared resource. Certain levels of licensing is for 'amateurs' and other licenses are for more industrial things, like TV and what is commonly referred to as FM or AM radio. Communication with satellites in the US requires the highest level of amateur…

Actually, you can talk to satellites[1] using a technician license, because they use VHF/UHF. A general or extra is required for using certain HF bands. [1] http://www.arrl.org/getting-your-technician-license

This is great news, although I feel I want to keep studying for the Extra for the ham cred that comes with it ;)

Re: Dutch radio amateurs image far side of the Moon using Chinese satellite data

#42

Post by syntaxing » Wed, Feb 06, 2019, 2:01 PM UTC

So interesting! How do you send "error-resistant digitally modulated transmissions"? Is that the same thing as a duplex signal? Is there other technology used nowadays?

Re: Dutch radio amateurs image far side of the Moon using Chinese satellite data

#43

Post by moftz » Wed, Feb 06, 2019, 2:33 PM UTC

Tor3 wrote: post #32

pvitz wrote: post #21

This is amazing! I have a background in physics and electronics, but I have never been involved in amateur radio. However, I would love to and would like to ask if one could point me to resources for delving into it? When it comes to math and e.g. electrodynamics and practical filters, I wouldn't need an introduction. Thanks!

What I did was to find the local club, go there, learn about the next course & exam, and focus solely on learning morse code (because I wanted the full license). Because I had an electronics&radio background I didn't have to spend any time on that part, I could focus all my time on the specific amateur radio regulations (not difficult) and learning morse (although IIRC I still had to take a written exam about radio t…

CW coding hasn't been a requirement at any level for 12 years. Its good to know but unless you want to do HF, it's irrelevant.

Re: Dutch radio amateurs image far side of the Moon using Chinese satellite data

#44

Post by stevespang » Wed, Feb 06, 2019, 2:53 PM UTC

Substantial power in the equipment viewable in the image of the private "mission control" room, on far right hand side of image . . .

Re: Dutch radio amateurs image far side of the Moon using Chinese satellite data

#45

Post by jandrese » Wed, Feb 06, 2019, 3:15 PM UTC

consp wrote: post #14

amelius wrote: post #8

Earlier quoted context omitted.

Doesn't sound very Dutch either ...

The encoding isn't, that is true. That part was about the team on the ground at the Dwingeloo 25m telescope. The (old) 25m telescope is now run by volunteers.

Most people don't appreciate just how big a 25m dish is until they are standing next to one. The fact that one is being run by volunteers is remarkable.

Re: Dutch radio amateurs image far side of the Moon using Chinese satellite data

#46

Post by jandrese » Wed, Feb 06, 2019, 3:17 PM UTC

lixtra wrote: post #11

Isn't it a copyright infringement to pick up some radio signal, reassemble it to pictures and publish them?

Depends on the wishes of the people who originated the signal. There are plenty of OTA signals that are free to the public, like NOAA weather satellite data. They're paid for by the public and are in the public domain. I don't know specifically about these signals, but it seems like the Chinese government is pretty open with them as well.

Re: Dutch radio amateurs image far side of the Moon using Chinese satellite data

#47

Post by howard941 » Wed, Feb 06, 2019, 3:17 PM UTC

lalo2302 wrote: post #5

> designed by radio amateur and Nobel prize winning astrophysicist Joe Taylor He doesn't sound like an amateur at all

"Amateur" here is a term defined by treaty. Radio Amateurs are prohibited by law from receiving compensation for their activities (in the US W1AW's paid operators get an express exception). Furthermore, the comms themselves can't have commercial purposes and often can't involve non-amateurs if the communications displace commercial services.

If the aviation world used similar terms a private pilot would be called an amateur pilot.

Re: Dutch radio amateurs image far side of the Moon using Chinese satellite data

#48

Post by moftz » Wed, Feb 06, 2019, 3:20 PM UTC

pvitz wrote: post #21

This is amazing! I have a background in physics and electronics, but I have never been involved in amateur radio. However, I would love to and would like to ask if one could point me to resources for delving into it? When it comes to math and e.g. electrodynamics and practical filters, I wouldn't need an introduction. Thanks!

You can get all the books to really learn the material (the ones by KB6NU are the best) but if you already have the background you can just study the test. I use an app called Ham Test Prep on android to take quizzes that basically amount to flashcards. Once you learn most of the questions and answers, you can pass pretty easily.

Re: Dutch radio amateurs image far side of the Moon using Chinese satellite data

#49

Post by superkuh » Wed, Feb 06, 2019, 3:23 PM UTC

pvitz wrote: post #21

This is amazing! I have a background in physics and electronics, but I have never been involved in amateur radio. However, I would love to and would like to ask if one could point me to resources for delving into it? When it comes to math and e.g. electrodynamics and practical filters, I wouldn't need an introduction. Thanks!

The Society for Amateur Radio Astronomy (SARA) mailing list and website (http://www.radio-astronomy.org/) should be your first stop. There's also a decently active (daily) radio astronomy news feeds/forum over at http://notabug.io/t/radioastronomy . Like others have said, cheap SDR receivers like RTL-SDR based devices have made it easy to get involved.

Re: Dutch radio amateurs image far side of the Moon using Chinese satellite data

#50

Post by Tor3 » Wed, Feb 06, 2019, 3:24 PM UTC

moftz wrote: post #43

Tor3 wrote: post #32

Earlier quoted context omitted.

What I did was to find the local club, go there, learn about the next course & exam, and focus solely on learning morse code (because I wanted the full license). Because I had an electronics&radio background I didn't have to spend any time on that part, I could focus all my time on the specific amateur radio regulations (not difficult) and learning morse (although IIRC I still had to take a written exam about radio t…

CW coding hasn't been a requirement at any level for 12 years. Its good to know but unless you want to do HF, it's irrelevant.

I only want to do HF.. but that's outside the point, I did write that this was a long time ago, and at that time you did need CW to get the full license.