How to Find Out the Owner of a Feed on Broadcastify

Hey, just wanted to say thank you. I'm in the Twin Cities (Mpls/St Paul MN) and I've absolutely been on Broadcastify for hours in the last week. On Friday/Saturday night things were getting pretty wild near my house, and being able to hear where dispatch was reporting incidents was really helpful in being able to calibrate my sense of personal danger, to be frank. Just sitting on the front porch listening to the scanner and watching for cars with no license plates the last few nights... and using what I hear on the scanner to try to convince the guys with their impromptu militia that they ought to at least sit down in f*(&ing lawn chairs to indicate they're local instead of pacing around after curfew looking like the very folks we don't want to see (they had the police dispatched on them 3+ times). Broadcastify, Unicorn Riot, and some select trusted sources on Twitter have helped me understand much better what is going on as these protests unfold.

I don't have any questions but I'd just like to say how much I love what you're doing, thank you. When I was a kid I loved geeking out with my scanner I bought at radio shack, your site relights this flame for me and it's awesome to explore all of broadcasts going on in the world through your site.

Thank you for the kind comments. I started out in the hobby the exact same way, my parents got me a scanner for Christmas and I was hooked ever since.

Isn't police radio usually scrambled? It is where I am in Norway. It was legal to listen to it before it was scrambled though. Not sure if it's legal to de-scramble it, if it's at all possible. AFAIK you can still listen to the ambulance channel, though, but sometimes the details are ... grisly.

In the United States, no. Police, emergency, first responder radio transmissions are generally in the clear. I don't know the precise history of it, but I have always assumed it is a combination of legacy (emergency radio in the United States is very old, and predates cheap and convenient electronic encryption standards), compatibility (first responder funding and maintenance in the United States is generally a local and state issue, so practices vary widely; for anybody to successfully come up with an encryption standard would require an unusual top-down standardization that has only been seen in extraordinary circumstances, such as after September 11th), and utility (in a disaster scenario where disparate groups coming from disparate points of the country might need to quickly ad hoc communications with each other, the absolute last thing you want is lives on the line while people are configuring their encryption protocols for their radios... Nor do you want to deny local volunteers the ability to understand where first responders are and how to get to them by having that information communicated in scramble).

This is starting to change, but it does take time since it usually requires replacing hundreds of radios at one time and a bunch of additional training on how to use the new radios properly.

A friend of mine in Little Rock connected the dots on how police were ignoring burglary reports en masse to rig the stats in favor of businesses and realtors with a vested interest in lower perception of crime than there really was. The radios were encrypted to stop him from doing so within the next calendar quarter. He was plotting dispatch calls versus FOIA reports of burglaries to find the variances. I'd expect this to be a growing trend. Local political corruption is ubiquitous in USA, that's why they accuse every other country of it.

I do not live in the USA, and I do not want to politicize my question. I am clearly asking out of curiousity: Would that be something related with the way that voting areas (whatever they are called in the USA)/Gerrymandering is causing? Area-X on the map (that doesn't have any straight/simple lines in its perimeter!!!) has data hidden, while Area-Z seems to have "all the problems"? Apart from real-estate fraud, I am trying to imagine what other areas of life may this impact. (again I am NOT using -alphabetically- Dem-Rem notation)

The problem is multi-faceted and money explains most of it. The fact that wealth is associated with racial prejudice is tangential. 1) In the USA there is very little concern for local elections compared to say, the presidency. Most people don't even know who their local elected officials are, and most don't show up to vote in elections that only concern local issues. The only people who participate in local politics are those who have a business interest in influencing local political offices. 2) Yes, a lot of this can be studied with geo data, from both sides of the coin! From the standpoint of the police, maintaining a presence in multiple areas of a city is a matter of time and distance. How long does it take a police car to go from the dispatch location to the scene of a reported crime? From the standpoint of a criminal who is robbing houses, there's a consideration of "how long is it going to take police to get here" if they see that police have no presence in an area outside of the times when a crime is reported. You can also see disproportionate enforcement of criminal laws based on property location. A lot of people don't want to see house prices negatively affected by crime statistics in wealthy areas. When a kid from an affluent part of a city gets caught with illegal drugs, for example, you won't see a large police presence in the neighborhood showing up to investigate. More police means more reports, and reports become statistics, which then in turn negatively affect property values. On the other hand if a poor kid from an apartment in a poor neighborhood gets caught with illegal drugs, the police will happily go there and harass adjacent residences, cars, neighbors, and for lack of a better word turn it into a fishing trip to try and find more petty crimes to charge more people with. 3) Local tax revenue in the USA is mostly from two sources: retail sales taxes collected at the point of sale in stores, and yearly taxes on real estate. A lot of retail sales tax was lost when people began shopping online more than shopping in stores in the past ten years. Most larger online stores now collect and pay local sales taxes (like Amazon) but they did not do so initially, it has only recently been required of them to do so. Prior to changes in local sales tax laws, the responsibility to pay sales tax ultimately fell on the customer rather than the store. Due to that, the reliance on property taxes was even more prevalent than it is now. (1) 4) There is no profit in jailing criminals. There is profit in releasing criminals after charging them fines instead of sending them to jail. Again, for the purpose of maximizing government revenue, there have been efforts to jail fewer non-violent criminals and instead charge them fines and let them go. This is especially the case when there are quite literally financial services built upon paying bail and fines in the USA. Lets say a burglar is arrested robbing a house. It might take 6 months to a year to give him a trial, so unless he has some sort of demonstrable violent criminal history a local judge will simply charge him a bail fee and let him go. Presumably he can't pay the fee, so there are local bail loan services in the USA that, for typically 10% of the amount of the bail, will assume the risk of the burglar not showing up for his trial for him. So the burglar won't have to pay the 5,000 dollars bail he was assessed, he will only have to pay the bail bond company 500 dollars. (2) (1) Property taxes are not entirely objective. In most places in the USA, people pay property taxes based on appraised value, not on actual realized gains or losses. For instance, if you buy a house, in the first year after the sale you will be charged property tax based on the price you paid for the house, but in subsequent years the local government will compare your houses to sales of similar houses in your neighborhood. If prices rise, they will charge you more based on the assumption that your house has increased in value. (2) For the most part local judges are elected, not appointed, so they can be bribed with campaign contributions from bail bond companies who don't want those judges to compel them to pay for accused criminals who don't show up for trials.

This is fascinating, and seems like the kind of thing a national-level investigative reporter would love to cover. Has it been covered anywhere or pitched to anyone?

It would require some pretty high end text-to-speech tooling, or a lot of manual labor. In the single city case he had volunteers check the text-to-speech outputs and manually fill in addresses that were missed. His accuracy rate was quite low with 2014 tools so it was a lot of manual work to transcribe the addresses from the recordings. I suppose text-to-speech tools are better since then, but these recordings are still quite dirty. You're talking analog radio recordings of poorly trained personnel who have regional accents, mumbles, inconsistent phrasing, etc. Try to find tooling to get good text-to-speech accuracy from some sample source like the recordings on liveatc.net (air traffic controllers) and see how accurate your results are, noting the difference between controllers (who are trained in proper phraseology and speaking techniques) and pilots (who are not).

Denver's is gone too. i've wondered if the solution might just be a 'lost' scanner - but I don't know the technical details. Are keys rotated? Are the 'hard wired' into devices?

Can't they run a newer encrypted system on separate channels than the older system is using, with some kind of repeater set up between the two? You'd need to upgrade at the base station upfront to have both the old and new systems, and add a repeater, but you could then take your time replacing the radios in the field instead of having to replace them all at once.

Sure, but as long as a single unencrypted bridge is running, anyone else within range of that bridge can listen, so you won't really get significant benefits of encryption until the switchover is complete.

Yeah, San Jose just scrambled theirs 6 weeks ago. One article from 2015 claims only 2 departments in California did this for the primary radio communications, so things are changing that way.

I understand the desire to be able to listen in/oversight during riots and conflicts between demonstrators and police. It make less sense in cases where someone is a victim of a crime or a patient being transported as such individuals are protected from the public prying eye. When recording devices and storage is so cheap as it is now it should be assumed that any communication traveling in clear is captured and stored.

>>It make less sense in cases where someone is a victim of a crime or a patient being transported as such individuals are protected from the public prying eye Few things there, first "victim of a crime", most area's criminal reports are public records as they should be. Allowing the police to operate in secret is a very bad thing Further outside of location information is a rare that other personal info is transmitted over the air anyway, general descriptions etc sure but... Finally I think the public value, and transparency we get from having open air dispatch far far far far outweighs the limited privacy concerns. People say the same things when police are mandated to wear body cams, just like in those situations the public right to know what the police are actually doing far outweighs some minor privacy concerns. We need FULL transparency in policing right now.

Here in Sweden, the public record goes in effect only after the investigation has been closed. Before that it is kept secret. The record can also be partially hidden in some circumstances in order to protect the integrity of the victim. And even when its public record, there is a large consensus that some of it should not be published to a larger audience. There was a now old incident where pirate bay had a torrent of a public record covering the investigation of death of several children. It was one of the few torrents that if I recall right, the pirate bay voluntarily took down. A lot of people commented that police should have used more discretion in what they put in the public record. Body cams has the same issue. It is good that they exist. There is however cases when the record should be kept secret. The default should always be transparency, with exceptions when there is good reason to keep it away from the public. As a obvious example, the body cam recording from a police arriving to a rape scene with the undressed victim should not be public record.

Before they scrambled the police radio in Norway, they would sometimes phone in stuff to the central when they wanted to deliver personal or protected information. Sometimes they'd omit the phone-in, though, to save time. Interestingly, tapping in on mobile phone conversations, and de-scrambling them, is legal in Norway, at least for the state. AFAIK they still don't need a court ruling to do so, like they do when they want to wiretap someone. This is because the radio waves aren't regulated the same way as wired connections in Norway. I suspect this might be similar in the rest of the EU as well (of which Norway is merely a de-facto member). It might also be something to look into if you're an American, to check whether this is also reflected in either federal or state laws.

there are channels of police and other agencies that can be encrypted, generally of course for the police to be encrypted the local municipality needs to decide to do that and pay the bills, hence it doesn't happen - which is a good thing. I'm thinking a traffic analysis app https://en.wikipedia.org/wiki/Traffic_analysis might be useful for when encryption becomes more widespread.

Afaik some channels are encrypted and there is no way for normal people to listen in on those. But majority of "normal" police and emergency response channels are not, and those are the ones you can tune in to on those websites.

It would seem reasonable to be able to FOIA the encryption keys in US locations where it is encrypted.

Doubtful. https://www.foia.gov/faq.html > Exemption 7: Information compiled for law enforcement purposes that: (A) Could reasonably be expected to interfere with enforcement proceedings I'd fully expect other exemptions to apply if you FOIAed the White House's SSL private key or something.

I'm Canada, usually you have to give everything to the FOIA department, and then they redact it. I think that would make the keyholders soil themselves if they had to send the keys over even for a second like that.

FOIA is a federal law. Each state has its own law. For example, Texas's is the Texas Public Information Act (TPIA). The standards could vary state by state.

Even if you could, how long do you think your FOIA request would take to get processed vs. the rekeying frequency of the encryption?

I was investigating starting a small personalized Scanner app with an AI twist but found that you're no longer granting licensees for mobile app developers - basically stopping all innovation in this area. "The broadcastify audio feed catalog API is only available to approved licensees. We are currently not issuing addtional licenses to mobile device developers at this time. " Can you explain the rational here?

Yes, it's pretty simple. There has been a proliferation of apps that all do the same thing - front end our feeds, and so we're protecting the investment that our core partners have made to write apps. We are extremely plugged in to AI efforts that are occuring around the use of our feeds, and so we have a pulse on what is going to work and not going to work in those area. You are more than welcome to use the feeds to develop AI models and present that back to us so that we could grant an exception, but the simple reality is that 99.9% of developers that want access to our feeds are simply trying to get yet another scanner app in the marketplace. It just dulites the environment, cheapens the brand, and presents a race to the bottom scenario in the app stores. I'll readily admit that we don't "know it all" and there could be some serious innovation out there, but the app store market has left a serious bad taste in our mouth of nefarious actors who will go to the ends of the earth to make a buck vs innovate.

Just wanted to say I appreciate how candid and direct your answer is, even though it might be displeasing to some people to hear.

Really appreciate the feedback here. That makes good sense on the low quality money grabs.

Is there a text transcript feature for users who may want to search through the communications? I'm curious how well those speech-to-text tools work for the audio feeds.

Great to see you working on this! I was wondering if you could estimate what it would cost to have always on recording of all these radio conversations, cost of running this speech2text ML and cost of labeling this data. I think having these rough estimates will make donations easier for people.

I've got a year+ of the Ohio MARCS-IP site in Hamilton County Ohio recorded. Let me know if you need some data -- I'd be more than happy to get you the dump. (trunk-recorder + rdio scanner). The UI is: https://cvgscan.iwdo.xyz for the live stuff, but, let me know if you're interested in the data -- my email is in my profile

Great question! Unfortunately the long term costs aren't clear yet, right now I'm using google speech as a bootstrapping technique, but that is prohibitively expensive to run long term. I think once my models are viable enough to do this at scale, the cost will be basically the cost of running a dedicated server per N streams. So $100-300/mo per N streams? Where N could roughly be at least 100 concurrent streams per server. I will know this better in "stage 2" where I'm attempting to scale this up. It's also a fairly distributed problem so I can look into doing it folding@home style, or even have the stream's originator running transcription in some cases to keep costs down.

I suppose maybe you can try running it through Otter[1]. We've used it with varying degrees of success when interviewing customers, and it's also what powers Zoom's transcript feature which is what we use these days. It's hit and miss, in my opinion. It'll give you a good enough base to refine the transcript from, but I've yet to come across a transcript that doesn't need editing. (Which is annoying, since Zoom doesn't give you that option.) I'd say it's more valuable having the tool than not, but don't expect miracles. (I'm not affiliated with Otter or Zoom in any way.) [1]: https://otter.ai/login

Hi, this is a difficult problem but I've been working hard on it for a couple of days with some help. I have a pipeline and website that automatically transcribes scanner feeds that is working pretty well, and the website allows users to correct and vote on transcriptions. My goal is to train my own models on the corrected transcriptions (I work in the speech recognition space) so I can transcribe many live feeds inexpensively. I will respond with a link here (hopefully very soon today) once I've fixed a couple of remaining UX bugs.

I work in the speech recognition space and train my own models already. The existing open-source models aren't very good at noisy radio speech. I will specialize one of my models to this task once I have some data from the site.

As you're well aware but HN folks may not be, it's not just that it's noisy, it's heavily coded, contextually bankrupt speech between multiple parties that spend all day in contact with each other. Dispatchers in particular seem to have superhuman ability to extract information from completely unintelligible garbage. Are you doing any kind of speaker identification?

This is a very accurate description of the problem space. Every municipality has their own jargon, vernacular, and ways to communicate brevity which is key in public safety communications. The communications are often digitized over vocoders that are less than optimal, and then you have the process of recovering voice from noisy communcations channels. This is definitely a very hard problem to solve.

Indeed. The only reason I know is that I tried a few years back and realized that I was asking the computer to do something that I couldn't even do. Anyone that doubts it, just listen to the NYPD feed and try to transcribe for just a minute or two. https://www.broadcastify.com/listen/feed/32890 (edit: also, thank you for keeping this service up and running for so long, have been a regular user since the early RR days. Would love to have a comment/live chat option if your backlog is getting bare :))

Whoa this is awesome! Love the option to fix a transcription, should hopefully help with training if you get some traction.

Thanks! I did a lot of tests and no existing ASR I found could do it to 100%, so I'm using the best ASR I could find and hoping users will help with transcriptions if they want to see it succeed and scale.

I used your service to listen to emergency service radios during the recent Australian Bushfires. The fires got really close to my family's home, your service allowed me to keep up with what was going on in real time. It really helped. Thanks.

Is there a way of legitimately detecting Stingrays? I understand this is the kind of situation where they are actively deployed despite all the social awareness.

I guess if you were to build a map of static cell towers, it would be easy to see if a new one suddenly pops up.

additional temporary "towers" are sometimes added when very high but transient network loads are anticipated (such as a music festival, or county fair, etc.). not all new towers are sniffers.

If anyone is interested in trying to work around this, I have a few ideas for how to try distinguish a real and fake cell. Temporary event "pop-up" networks should announce valid neighbouring cells. Your baseband (radio) might expose neighbour cell data - iPhone field test menu shows the announced neighbour data. Hypothesis is that a rogue tower will not have valid neighbour cells announced. They could try listen in for valid ones and advertise those. A lot of the ways to detect will depend on the generation of network being spoofed - 4G networks will also advertise signalling for legacy 2G and 3G circuit switched networks. Rogue sites might not.

Sweet talk a cellular network engineer into giving you the engineering firmware for your phone and a list of all the cell ID's.

They can and do, but they and the other cell sites can't up and move around. All cell sites have multiple transceivers that are directional. Each site has a unique cell ID and each transceiver has a unique ID. Your phone has GPS. If you drive around, you can find out who doesn't belong. Be careful about publicly disclosing this information.

>Be careful about publicly disclosing this information. Why, what do I have to fear about that in the United States?

The creator of CryptoCat was targeted by the FBI. Not because he was suspected of committing a crime, just because they didn't like him creating open source encryption software. They actually had Hector Monsegur (Sabu) try to entrap him multiple times to try and come up with some trumped up reason to convict him. https://nadimkobeissi.tumblr.com/page/29 Moxie Marlinspike can't even fly domestically without jumping through hoops and travelling internationally means they try to seize his electronics and demand the passwords.

I suppose that depends on your tolerance for drama and legal cartooney. One of my former employers and a three letter agency would go after people publicly disclosing such things and the people always backed down. The cooperation between nations can blur the lines depending on what nation you are in. That said, I am not a lawyer so it is probably best to get their input rather than mine.

Does that work for DRM encryption keys? I think sony went after a few people who leaked either the blu-ray encryption keys, or the signing keys for one of their consoles.

You can look up where the towers are and perform triangulation on the ones that you are connected to given multiple antennae. It'll cost you some hardware and you'll probably be writing some software also. Another option can be just seeding a few phones around the area and have them report moving (or transient) towers.

Is there a way to report incorrect feeds? I was listening to our local scanner feed last night and growing increasingly alarmed at the amount of activity, until I realized that the scanner audio was actually for a larger city an hour away. I've listened before and it's been correct, but last night it was definitely not.

You can always open a support ticket with us. Feeds are provided by volunteers so we battle quality issues all the time. It's a tough problem to solve.

Interesting product/service! I've been familiar with it in the past but really used it a lot over this last week - thank you for offering a free n accessible tool. When, Why and how did you get into it? Does it generate meaningful/worthwhile revenue or is to more to cover overhead? (I only noticed the occasional 30 second commercial intro) Maybe you have a lot of premium subs? Why sometimes do certain cities/counties change their feed? For example one night the Minneapolis police were on a completely different county that was hours away. Majority of the time, these feeds are relatively low key right...with actual concerning/escalated incidents few and far between. Wondering: is there someway to us ML to identify specific things and provide push notifications to people in a given geography around that? For example it could listen for "shots fired" in a specific area and notify me via sms or whatnot when that occurs. And AI could be used to show more of an abstract map view if and when "violence" is rising based on action on the scanner, right?

My Grandmother had a police scanner that she used to listen to drama going on in her small town in Virginia. Old ladies with police scanners is still quite common. It sparked an interest and my parents got me one as a Christmas present. I spent many years in the IBM ecosystem as an technical SE, but developed an online database (RadioReference.com) in the late 90's that consolidated frequency information for all the municipalities around the world. When online streaming came to the Internet, I purchased a small business that was putting scanners online and launched it as Broadcastify. The business is wildly successful. Revenue is a split between paying subscribers, license and royalty revenue, and advertising. About 90% of the feeds are provided by volunteers who simply connect a radio to their computer and broadcast to us. The other 10% are actually provided by the agencies themselves. We probably turn over 20 feeds a day, so coverage comes and goes all the time. There is a lot of work going on in the ML / AI space around the content, but it is a hard problem to solve because the quality of the content diverges wildly. Vernacular differs. Coverage comes and goes. Organizations like Citizen, which have HUGE funding (60 MM lol!), are trying to solve this, but they still end up just employing armies of workers to sift through the data and audio and normalize it all. We're doing a lot of innovation in the space on our end, including using SDRs to vacuum up wide swaths of RF and then store call data, which is going to be the next "revolution" in our space. Interesting times...

> including using SDRs to vacuum up wide swaths of RF and then store call data Been there, done that. The technique is scary-good, even with cheap hardware. Capture everything, sort by talkgroups, form listen queues ("police", "fire", "police NOT university",) prioritize, and place recordings in queues. Stream queues through ice cast. Drop low-pri messages if you fall too far behind real-time. Speaking of: if anyone wants nearly two years of uninterrupted Seattle police radio archives (and everything else from KCERS), they should get in touch.

Im doing the same right now in Minneapolis. Running Hack RF and Unitrunker V2, tapped straight into Minneapolis City Center Multicast. I have a radio reference account so Unitrunker just syncs to its database and all that info auto magically appears. Here's my live youtube stream and archives: https://www.youtube.com/watch?v=LuCP1ZetSEA

Will unitrunker handle multiple simultaneous captures at once? One of the magical things about the SDR approach is being able to synthesize dozens of streams from a single antenna and several SDR devices. The setup I had could capture ~10 simultaneous transmissions before things started to fall apart.

I think there's a roundabout way to go about doing that. Essnetially create a lot of additional voice VFO's and then set each one of those VFos to have only 1 talk group with its priority set to 1. And then set the output of each VFO to a different VB audio cable in, then source would be VB audio cable out in audacity. The hack RF definitely supports grabbing an entire 20Mhz swath of bandwidth that covers all the signal and voice frequencies. Id be super curious to hear more about your setup, both hardware and software.

Can you elaborate on the current ML/AI work and the specific goals? I can think of a few cool use cases, but curious what all is being looked at. What organization do you mean by "Citizen"? Not aware of any major nonprofits that go by just this one word.

Right on thank you so much for taking the time to answer my questions...love the history, glad to hear it's "wildly successful" and godspeed to you and everyone else going forward.

I just wanted to weigh in here and say thank you for this service, I have been using it for quite some time now to monitor and follow emergency services in my area to report news. A truly awesome and bad ass service.

Thanks so much for providing this service! Here in San Antonio, there were over 1000 tuned in a few nights ago. Some local news channel management asked reporters on the ground to leave the scene quite early in the night, so this service was really invaluable in helping me understand what was going on in real time. The difference between live local news and reality on the ground was drastic at times. How did you get into this business?

Your site helps me know what's happening when I'm in Chicago. Robert thanks you for your service and for checking those keys. o7

Thank you so much for the possibility. I grew up with scanners and am truly reminiscing while listening on these intercepts. Here in Europe there is close to no police still using analog and listening to air traffic control or couriers just does not cut it for me. Bought the app, hope you'll be able to keep this up.

Every year new technology drives some agencies to remove their routine general dispatch operations from public access. Some agencies really like their communications to be publically available, and some don't. If I had to back-of-the-napkin it, I would say that 10-15% of all law enforcement general dispatch operations are encrypted full time. The vast majority in this country is still unencrypted.

In a few states it is illegal to use a police scanner while operating a motor vehicle unless you have a license from the FCC or permission from local law enforcement. Do any of those states consider those laws to apply to using one of those apps? PS: for those who live in one of those states (Indiana, Florida, Kentucky, Minnesota, and New York) a ham radio license counts, and the entry level ham license (Technician) is not very hard to get.

Any surprises with the uptick in traffic? Do you see increased usage ahead of news-reports of protests? Also: Thank you! I've been listening to Broadcastify both at the beginning of the Covid-19 outbreak and yesterday, to track nascent looting <2 km from our home.

The past few months has resulted in us seeing record traffic and revenue... it turns out that people stranded at home due to stay at home orders are thirsty for entertainment and information. I can't say that I'm really surprised by anything anymore after all that has happened over the past 3 months :)

We've abandoned flash as our default player long ago in favor of html5 audio. I'm not sure why you'd be seeing flash as a default unless you previously set flash as your default player.

When navigating via the map to Nevada, then Washoe County, the big button for "Launch County Web Player" defaults to the Flash version with no apparent option to change it. The other options below it seem to correctly default to HTML5, though, so I'm able to listen to RPD's radio chatter.

Is the poor audio quality a function of the participating scanners that feed your service, your infrastructure, or the current workload? My local feed is nearly unintelligible.

It is solely a function of the participating scanners. There is a report a problem link on each feed's page which allows you to let the provider know there is a problem. There are a lot of times providers simply don't know that there is a quality problem. Edit: there are also a lot of problem vectors. Poor reception, failing equipment, old equipment, and even the case of some providers that don't care and just rush a feed online just to get the premium subscription. Crowdsourcing content isn't always easy :)

Thank you for your service! FWIW, this was one of the things I wanted to do and learning about SDRs made that possible.

kelleyziese1971.blogspot.com

Source: https://news.ycombinator.com/item?id=23391158

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