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." : )

My dad was a HAM (W7AAI) and as a kid I found the frequencies for walkie talkies on his receiver in the shack. After Christmas I would tune in and hear local kids doing the "I can hear you, can you hear me?" thing with the new presents.

my family had a little portable TV (GE 7-7150B, link below) that we'd usually only use down in the basement during severe weather.

one day I learned that you could tune in all sorts of non-TV frequencies. In particular, you could tune into any phone calls my neighbors were making on their wireless phones.

i loved that little tv and used it up until the conversion to digital OTA tranmissions.

[0]: https://www.youtube.com/watch?v=N4qYPLd8owc

I expected the voice on the other side being your soon-to-be wife. But good story nevertheless. Congrats!

I brought a family-pack of walkie-talkies for my wife and my two teenage boys to use while we were hiking around various Austrian mountains, one summer vacation.

We rarely used them much, since we were often walking in a family unit, so during one of our breaks I took one out, turned it on, and blasted off into the ether "hello hello, anyone out there wanna chat?" .. did this off and on for the afternoon, when suddenly, a voice answered back "yes! who is this?" ..

A family waaaaay the hell down the mountain rage, deep in the valley, had by chance heard my call .. so the boys spent the afternoon getting to know all of the 5 kids in that family that were all drawn to the conversation.

It was awesome, for the rest of the week, our kids and theirs just chatted away .. what had started out to be, a little bit of a mundane trip for the kids, turned out to be a hilarious social experience.

We call for them every time we're out that way - never met them, but for the past 3 years, the conversations have continued and it has been a great alternative to the mobile phones we have been troubled with up in the cabin, at times.

This is awesome, and future congratulations on your wedding!

damn, that's awesome.. I feel like I just watched the opening scene of a nice "stand by me" type movie.

This is awesome, and congratulations!

I got chills reading this. Congrats!

Awesome story and well told

> Brazilian outlaws and UHF pirates using open repeaters on US military satellites launched in the 70s

This is still happening? I'm sorry but that's hilarious!

https://www.wired.com/2009/04/fleetcom/

The receiving IR remotes with an SDR by connecting an IR photodiode across the antenna input sounded like nonsense to me. I googled and could it be you meant people using the IR receiver feature of the RTLSDR's? It may still require connecting a photodiode, but to a different set of inputs.

https://medium.com/@rxseger/receiving-ir-signals-with-rtl-sd...

As to connecting a photodiode to the antenna input, I don't see how that would work, but that may well be due to my limited understanding and imagination.

Do you mean using the photodiode in a photovoltaic mode? Also, presumably you'd have to bypass the tuner and hook to the direct sampling pins on an RTLSDR? Even with direct sampling, wouldn't the 38kHz of IR remote modulation get filtered out by the DC blocking?

  remotely read a nearby screen

Displaying malicious image causes HDMI cable to emit LoRa packets, https://github.com/XieyangSun/TEMPEST-LoRa

  passive radar

SEC-T 0x11 (2025) on evil maid defense, https://www.youtube.com/watch?v=ScwNIWzk4RQ

> Do you like feeling safe about leaving your expensive stuff in your hotel room? Have you ever had anything stolen out of your room, or discovered someone has gained access to your room while you weren't there? .. what about .. other rooms? Maybe not EXACTLY a hotel room? I've presented on securing hotel rooms in the past, but adding home assistant, zwave devices, co2 sensors and millimeter wave radar it's become a whole new game

  SDR is amazing!

> We use the GNURadio software along with RTL-SDR and ADALM-PLUTO hardware to explore the world of digital communication. We build up to a simple QPSK modem and rudimentary GPS reception.

LibreSDR firmware, https://github.com/F5OEO/tezuka_fw

> official [PlutoSDR] firmware updates are no longer focus on new features for SDR enthusiastic people.. tezuka.. aims to be Universal Zynq/AD9363 firmware builder for.. PlutoSDR, Pluto+, AntSDR (e200), LibreSDR

The fact that there's a mature product doing what you want to do is a good thing. It means there's a market for what you want that's large enough to sustain development.

You can easily distinguish yourself from Citizen by targeting a different demographic, different branding, different UX, interpreting the data in a different way.

Just look at how many businesses there are in any industry that deliver the same outcome for their customers but in a slightly different way.

What you're describing could be a really good news source giving live on-the-ground information to people.

I don't know about billion dollar ideas, but I encourage you to make a product even if something similar exists.

If you squint enough there is nothing new under the sun and chances are that you will take a very long time to find something that hasn't already been done!

But doing your own product does several things - you learn a lot, you position yourself for future success, you see future ideas differently. And maybe you're okay for something to not be a billion dollar idea and you can outlast a venture funded product.

Maybe I'm just projecting, because I've put of building something for such a long time!

Citizen is really enshittified, so any alternative would be better. I don’t object to them charging for their service, but they use all kinds of predatory editorial tactics and push notifications and marketing copy to instill primal fear that your neighborhood is imminently burning down and you will get shot if you don’t subscribe to a higher tier of service from them. Crime is way down in the US but you really don’t feel that way when you are a subscriber/user of Citizen.

> A few months ago when there was a lot of emergency services activity in my area and I didn't know why, I was reminded that no-one in my region is contributing a feed to Broadcastify.

Maybe instead of emergency services activity, it could be other types of activities (hazards, local events, nextdoor alerts, local business/SIGs rss feeds, etc), it is all just local info and knowledge aggregation endpoints and archives that have over-the-air and terrestrial distribution channels.

You can buy the kit on Amazon for the GOES satellites. Pretty easy to do

https://a.co/d/d7pCLGd

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?

Where can I find more info about this? Ie: type of antenna needed, etc?

Oh that's too bad, I had done this in the past and it was good fun.

Look into Rainforest Automation. I have their EMU-2 which can be paired with my electric meter. It spits out XML data which can be read by Home Assistant.

https://www.rainforestautomation.com/rfa-z105-2-emu-2-2/

A number of smart meters communicate over the mains wires, especially when they're in very sparse areas. There was even a thought for a bit to offer internet services over the power distribution cables, but I don't think they ever really got effective data rates high enough to be competitive.

I have a v5 and have had no issues with Fedora 42 btw. Worked out of the box.

When I was installing it I actually came across the Ubuntu installation notes only to find I didn't need to do any of those things on my systems.

> capturing info from TPMS sensors off of passing cars

... sitting on a porch, yelling "Check your tires!" at random cars...

Your stories were delightful. Really smile a lot reading seeing you enjoy this. Inspiring!

A lot of the 433/915 band devices you can pick up with rtl_433 seem to be much more bullet proof and have longer battery life than equivalent WiFi and Zigbee devices too. Building new protocol decoders for rtl_433 also surprisingly isn't too bad either. One of my favorite ones is the water meter decoder which has saved me a lot of money when I've had irrigation water leaks and not noticed them (but saw conspicuous usage patterns reported).

I was hoping to find more devices around me which use 433. Apparently my neighbors don't have any 433MHz devices.

Same experience here with hospital pagers. I tried this way back in 2013 when I first started with SDR. Even without covid, the messages were hideous and depressing. Not recommended.

Listening to pagers is illegal in US from ECPA of 1986. It is the same law that banned listening to the analog cell frequencies, which still applies even thought that is long gone.

There is no way that they will know or care if you don't share messages.

very unlikely. you may have read some text pages but not enough to get anywhere near the type of picture you're claiming.

https://khanfar-spectrum-analyzer.web.app/ also has some phase-based direction-finding software and upcoming hardware.

For triangulation though, if you have a reference signal at a known location, TDoA (time difference of arrival) requires less hardware (just a single receiver at each location, e.g. an RTL-SDR). I don't know of any open-source software which does that though I've been slowly building some for my own use (it's pretty janky at the moment).

One of the people in my local radio club did a demonstration of tracking down a commercial operation using amateur radio frequencies with the KrakenSDR. It's very impressive. I think the timing would be much more difficult using off the shelf dongles.

Cool!

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.

What's even more interesting about this is that anyone flying their own personal plane would generally be expected to be listening to others on their same frequency (and sometimes this helps prevent accidents). So in that sense, the ATC messages are "meant for any member of the public who happens to be flying a plane nearby".

But apparently the government of Germany doesn't quite conclude the same thing from that which I do.

Similarly, the government of Germany (apparently?) seem to make the distinction that decoding signals from a neighbors IoT device is not restricted like other "messages not meant for the general public", so honestly there's probably a lot of nuance that a naive outsider is completely missing.

Germany signed the Rome treaty so you can legally ignore that bullshit law.

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?

There is SDR++ : https://www.sdrpp.org/

Check out saveitforparts on youtube, he does lots of this stuff.

For HF, look at the technical articles by PA3WFM for the WebSDR at utwente.nl, especially this one: https://www.pa3fwm.nl/technotes/tn07.html

TL,DR: you probably don't want a random wire for HF reception, but either an E-field whip antenna like that one, or an H-field loop which will likely be larger and more expensive, but will have useful directional properties that the whip will not.

If you want to hear amateur radio conversations, check for regularly scheduled 'nets' in your area. Search for "$yourcity amateur radio club" and they'll probably have some details.

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.

Sure, the kinda go-to for this is rtl-sdr.com's device (just search amazon). They have a great and comprehensive site, too: https://www.rtl-sdr.com

FWIW, if you have an SDR that doesn't work with the frequency you want to work with, you may be able to use an up-converter or down-converter in front of the SDR to shift the frequency enough to work. There are ones like the Ham It Up[1], etc. that may be appropriate depending on the circumstances. Or you could possibly build your own.

[1]: https://www.nooelec.com/store/sdr/sdr-addons/ham-it-up.html

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

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.

"modern equipment" uses all KINDS of different frequencies, so that statement doesn't mean anything :/