I got a walkie talkie set as a Christmas present when I was 8. Which was kind of an evil thing to do given I had no siblings or friends to play with. One day I turned one set on and listened for a while and I thought I heard someone talking behind all the static noise. So I said something and was shocked to hear the voice talking back to me. Fast forward a few decades, next week is my wedding and that voice on the other side of the radio is my best man.
mtlynch · 6m ago
Congrats! That's such a cool story!
>Fast forward a few decades, next week is my wedding and that voice on the other side of the radio is...
I think I've seen too many rom-coms because I was sure this sentence going to end with "my fiance." : )
brulard · 6m ago
I expected the voice on the other side being your soon-to-be wife. But good story nevertheless. Congrats!
fullstop · 9m ago
This is awesome, and future congratulations on your wedding!
Sadly, you can't really get NOAA satellite images any more. NOAA-15 and 19 were decommissioned August 19, 2025, and NOAA 18 was decommissioned in June. It's my understanding that you'll need a much more powerful antenna to get images from the new satellites. Still, SDR is great fun. It's incredible to realize that all this information is stored in electromagnetic waves and passing through us all the time.
egorfine · 45m ago
I wonder what does it entail to have a NOAA satellite decommissioned? Is it just turned off or is it directed to fall down into a designated area in the Pacific?
megaloblasto · 43m ago
They will continue to orbit for about 150 years, slowly falling towards earth until the drag from the atmosphere burns them up.
"Like many older satellites, the POES satellites do not have thrusters to support a controlled reentry into Earth’s atmosphere at the end of their mission life. Instead, once passivated, they are safely powered down, placed in a non-operational state, and left in a stable orbit. Without onboard propulsion or significant atmospheric drag at their current altitude, NOAA estimates they will remain in orbit for roughly 150 years before gradually reentering the atmosphere and disintegrating."[1]
I depends on the orbit. The low Earth ones would usually be de-orbited and fall back to Earth. The geosychronous ones are usually just moved to a parking orbit out of the way to make room for more. If it's in a high but not very crowded orbit, they might just stop using it.
EvanAnderson · 34m ago
Receiving 433Mhz sensor data using rtl_433[0] with an RTL SDR was a lot of fun when I started doing it last year. There's MQTT output if you want to send it to Home Assistant, et. al., as well as simple text output to stdout. It was great fun seeing my neighbors' sensors, tire pressure sensors in passing vehicles, etc.
There a ton of devices that use 433Mhz. You can also extend rtl_433 pretty easily.
I was hoping to find more devices around me which use 433. Apparently my neighbors don't have any 433MHz devices.
EvanAnderson · 6m ago
I'm spoiled. One of my receivers is on a second story and has great line-of-sight to a bunch of houses and a parking lot (where I assume I get a lot of my TPMS "hits").
ortusdux · 28m ago
I've been wanting to experiment with SDR triangulation. There are some off the shelf options, but I think it would be fun to cobble something together using dongles.
Astonishing! Thank you very much for sharing..
This sentence really stuck out for me - "I was proud! I was tired! I was amazed that all those things I received are all around us, everywhere, all at once – if you know where to look. :O"
ge96 · 22m ago
Like 13 years ago when I was doing FPV I remember soldering my own skew-planar/quadrifilar antennas with bendable wire ha, the photo of the short yellow dipole reminded me of it. I think it's a dipole or double-dipole not sure.
edit: I think it's just a dipole
a1o · 48m ago
Over a decade ago I played with SDR sharp and a tv dongle and got to listen to very cool stuff. I don’t know if SDR sharp still exists, I think it was closed source at the time but free. I remember one could use it to decode stuff and then map to virtual ports to redirect to other software that expected an input from specialized hardware like ship signals and stuff like that.
This page was very slow to load for me, probably partly because it's being hugged by HN. But it would help a lot if images had the `loading="lazy"` attribute, and if they were compressed to about ~100KiB each instead.
Mountain_Skies · 51m ago
Hope they have an unlimited bandwidth plan. I bailed out at about #20, which is unfortunate because it's otherwise a nice list. I'm going to assume 51. Get a Free Kia, isn't part of it.
rlmineing_dead · 40m ago
I have a USRP B210 and its great fun for many things. One of my favorite things to do is create a small 2G GSM base station to use old phones!
fgbarben · 9m ago
You say this as if it's an easy thing anybody might do -- like putting flowers in a vase in the kitchen. Isn't it pretty complicated?
clueless · 42m ago
more than 15 years ago I got a chance to play with gnu radio and back then it was hailed as the next big industry.. fast forward, and beyond the hacking community (and the hobbyist), it still has not taken over.
NoiseBert69 · 42m ago
It's super popular within the RF industry.
But for the normal users - to be honest - most topics are too heavy on complex math. And there's no way to avoid it if you want results.
Most advanced radio stuff much more complicate than checking out a repo from GitHub and compiling it.
dummydummy1234 · 22m ago
My impression is that gnuradio is fine for prototyping/poc, but has issues in its design when you try and run production workloads with more complex workflows (ie, writing custom Mac layers/ workflows that involve heavy feedback, etc. you end up having to do a a lot of hacking around with the message passing infrastructure).
That being said last I used it extensively was v3 so maybe v4 is better. Did they get rid of thread per block and allow you to have a single thread service a sub signal chain? I remember that the number of context switches between threads, and balancing latency vs buffer sizes was a pain in the rear.
amelius · 38m ago
Is there SDR for the GHz range of signals used by modern equipment?
rlmineing_dead · 34m ago
You can get an AD9363 clone of the USRP b210 online for like, 300 USD?
The AD9363 stock is only supposed to be 325mhz to 3.8ghz but stuff like the plutoSDR which uses it manages to get the transceiver all the way from 70mhz to 6ghz like the more expensive AD9361 used in the real USRP B210s
Benefit is you can transmit stuff too, not just receive unlike the RTL-SDR which is RX only
Bender · 25m ago
Is there anything like this that can go down to 15 MHz or lower? including transmit and several analog modes of modulation USB LSB NFM WFM AM CW at least
kavouras · 4m ago
If I understand what you're saying, you can do any modulation scheme with sdr, it doesnt depend on the model
megaloblasto · 34m ago
HackRF One can go up to 6GHz ($400 new or $100 on alibaba for a similar device). Any higher frequency than that you'll be paying thousands.
amelius · 8m ago
Looks cool, except it uses USB2 which seems rather limiting in view of bandwidth.
rlmineing_dead · 32m ago
Yeah I dont know any SDR above 6GHZ but also other than mmwave 5G I also dont know much radio that is above 6Ghz in general
privatelypublic · 56m ago
Pictures are loading at a crawl, had to bail because the layout kept rerendering.
Looks like hug of death strikes again!
film42 · 1h ago
Very cool post. If Jeff Geerling is reading this, I wouldn't mind watching a video on each of these ;)
>Fast forward a few decades, next week is my wedding and that voice on the other side of the radio is...
I think I've seen too many rom-coms because I was sure this sentence going to end with "my fiance." : )
It runs on an Orange Pi Zero 3 SBC.
"Like many older satellites, the POES satellites do not have thrusters to support a controlled reentry into Earth’s atmosphere at the end of their mission life. Instead, once passivated, they are safely powered down, placed in a non-operational state, and left in a stable orbit. Without onboard propulsion or significant atmospheric drag at their current altitude, NOAA estimates they will remain in orbit for roughly 150 years before gradually reentering the atmosphere and disintegrating."[1]
[1] https://www.nesdis.noaa.gov/news/legacy-orbit-noaa-decommiss...
There a ton of devices that use 433Mhz. You can also extend rtl_433 pretty easily.
[0] https://github.com/merbanan/rtl_433
https://www.crowdsupply.com/krakenrf/krakensdr
edit: I think it's just a dipole
https://web.archive.org/web/20250908132643/https://blinry.or...
But for the normal users - to be honest - most topics are too heavy on complex math. And there's no way to avoid it if you want results.
Most advanced radio stuff much more complicate than checking out a repo from GitHub and compiling it.
That being said last I used it extensively was v3 so maybe v4 is better. Did they get rid of thread per block and allow you to have a single thread service a sub signal chain? I remember that the number of context switches between threads, and balancing latency vs buffer sizes was a pain in the rear.
The AD9363 stock is only supposed to be 325mhz to 3.8ghz but stuff like the plutoSDR which uses it manages to get the transceiver all the way from 70mhz to 6ghz like the more expensive AD9361 used in the real USRP B210s
Benefit is you can transmit stuff too, not just receive unlike the RTL-SDR which is RX only
Looks like hug of death strikes again!