[HN Gopher] Listening to Satellites: A Journey with My RTL-SDR V3
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Listening to Satellites: A Journey with My RTL-SDR V3
Author : Asdrubalini
Score : 77 points
Date : 2023-04-27 10:56 UTC (2 days ago)
(HTM) web link (moh53n.medium.com)
(TXT) w3m dump (moh53n.medium.com)
| dekhn wrote:
| My grampa was a ham radio guy and he told me a lot of things. I
| was really amazed by shortwave and how radio could travel long
| distances by bouncing off the ionosphere. He also gave me a
| shortwave radio and I remember tuning into weird stations that
| would just say numbers in a funny voice ("numbers stations"). He
| even had a ham radio in his car and could dial phone numbers
| remotely through it.
|
| I never really got into ham, I'm still not much of a radio person
| (I prefer wired) but I still had fun playing with RTL-SDR;
| listening to my car's tire pressure monitors and various other
| things in the ISM band. Antennas are still fairly spooky magic to
| me, though.
| binbag wrote:
| Really fascinating and impressive!
| blantonl wrote:
| One thing that is so critical in RF exploring is antenna design,
| and you can see where the author learns that very quickly.
|
| It's kind of like the old adage in audio where you can have the
| best sources, AMPs, scalers, etc... but your speakers are the
| crucial component.
|
| In RF, it's really is about the antennas.
| procarch2019 wrote:
| Specifically selecting the right type of antenna and placing
| and orienting it correctly. Very easy for omni's (mostly).
| Terribly annoying for spatial or directional.
|
| Radios are fascinating. Optimizing and enhancing your radio
| capabilities is a black hole of time and money, but in return
| you gain knowledge and satisfaction.
| ajsnigrutin wrote:
| It's interesting to me, that these things were almost
| impossible to do correctly in an amateur setting (equipment
| needed was a $10k+), and now with devices like NanoVNA, SDR
| dongles and some aliexpress shopping, you can do everything
| for a price of two prime steaks at a local restaurant.
|
| NanoVNA to tune the dipole (1/4l), gain is fixed, autogain
| off, move the dipole around the antenna with sufficient
| attenuation on the transmitter (or even better, rotate the
| antenna itself), and you can get reasonably accurate
| radiation graphs. Also tuning an antenna with a NanoVNA is
| very easy and if the antenna geometry is simple enough,
| orientation is simple too.
|
| 10+ years ago, you needed a friend working at a local college
| to take you in at night to measure stuff :)
| ge96 wrote:
| some cool videos on this topic by saveitforparts on YT
| mikub wrote:
| That's nicely written. Can't imagine how hard it must be building
| this stuff and getting all the components when you're living in
| Iran, it always reminds me that sanctions and such things are not
| only "hurting" the government but also, and probably most, all
| the normal people who just want to live a normal live.
| procarch2019 wrote:
| Originally I got interested in radios when I learned to deploy
| wifi for industrial applications. The big thing with industrial
| applications is interference and reflection. You typically have a
| lot of large structures made of metal or other materials that
| block the waves. Also, there's a bunch or rotating equipment that
| emits emf as well (interferers). This can make antenna placement
| critical.
|
| I wish I had gotten into it earlier, but I was discourage by a
| university professor who basically told my senior design groups
| that radios were too finicky for us to tackle.
|
| Now I participate in amateur radio and I suggest anyone who finds
| the topics interesting to do the same.
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(page generated 2023-04-29 23:00 UTC)