Even if you have no idea what you're doing, I very much recommend buying one of the RTL-SDR dongles on amazon for ~$20-30 and playing around. For the cost of a movie ticket, an afternoon messing with one will teach you a MASSIVE amount of stuff about how RF works.
Seconded. I was playing with mine last week and had it set up to read pager messages. Turns out that hospitals still use pagers heavily, and pager data is completely unencrypted.
Oh yeah, this has actually been a bit of a controversy in Vancouver recently[0][1], including speculation that the problem may be national. Local hospitals have now removed diagnosis data from the transmissions, but apparently still broadcast everything else, including "patient name, age, gender marker, their attending doctor and room number" (as of Sept 2019)[2].
Vancouver Coastal Health claims they "have no information to suggest private patient information has been used in any malicious way", which is a very disingenuous statement to make, because there's no conceivable way for them to know who has received radio transmissions or made use of such data maliciously. To be frank, I find this pretty mind-blowing and it's disappointing that even in the face of press/public attention, it's not being remedied.
Then set up a mock-up site at https://10.3.42.8/, and just show a journalist on your laptop. Ask to remain anonymous, then switch off your web server and let them know that "it has since been taken down, but anybody else could make a new one".
That's their story. They can then go on to describe the actual issues, namely the plain-text broadcast that made your proof of concept possible, and state in all honesty that it'd be ten minutes work for a bad actor to set up another, similar, site – and less to just gather (and later sell) the private medical data. Plus, it's not wildly unethical! (Might still be illegal, though.) This is drawing attention to an issue that they're well aware of, and are doing nothing about, in a way that minimises public access to these medical records – one could argue it's positively ethical.
… Though, actually, it'd probably be better to do to somebody in charge first, since perhaps only with such a mock-up would they truly understand. They might genuinely not be aware, thinking it's just some obscure issue.
Adding, just in case anyone wants to do this on their own: IANAL, but my understanding is that in the US it is not against the law to capture and decode these plain-text messages, but it is probably against the law to publish that information elsewhere or act on it in some way (an example from the link below was intercepting taxi service text messages in order to gain a business advantage for your own taxi business).
The text messages that float about in the ether these days aren’t messages between individuals, they’re monitoring alerts (refrigeration systems, computers), and medical (doctors being paged, order to clean hospital rooms, calls for medical transport). That’s the case at least here in my medium-sized town in the US Midwest. It could be very different elsewhere.
yeah! I had picked one up a while ago to play with it and had some fun and stashed it away for a while. Well last week i was BBQing and the receiver end of my little remote temp monitor stopped working. Found rtl_433 that already is setup to read the output from the sender portion and in like 10 minutes had it graphed on grafana with alerts for temps!
Can you show this off? It sounds like something I need to have in my life. What TSDB did you use? What did your conversion from rtl_433 to a metric look like?
Agreed! I picked one up and learned about ADSB protocol and usage, and now have a live view of the air traffic in my vicinity. Sure, I could use one of the websites that tracks that info, but there's something about viewing it on your own equipment.
Fun fact: Most of those sites filter out a subset of air traffic, notably military and anyone that pays to have their flight data suppressed (typically celebrities or other high profile people). If you run your own equipment you’ll see everything within range of your antenna.
The one notable exception is https://www.adsbexchange.com/, which actually allows you to just show just military aircraft or just aircraft that have been tagged as interesting (typically planes owned by high profile people like Bill Gates, large corporations, or news and police helicopters).
It’s kind of fun to zoom their map out to the continental US and put on the military filter. At any given moment there are a surprising number of military aircraft over the US.
I believe that’s correct. FlightRadar will actually give you a free pro membership if you run a receiver in your house (basically a Raspberry Pi, SDR dongle, and an antenna).
I tried to set up an SDR for my journalist girlfriend, and like the rest of you hackers, reading the manual, figuring stuff out and getting something working is usually pretty easy for me -- but there is a whole lot to software-defined radio.
What were you having issues with? Usually the RTL-SDR + SDR# (sdr sharp) works without any config. Once you start to look at more expensive devices like the Lime mini things get weird though.
It was a physical device and I was setting it up to read the police scanners. I do have problems sitting too long with documentation, though, I'm sure if I more patiently worked through it I could have set it up.
I lost complete interest in SDR due to the fact that antenna's are very important. I am ok with the tools etc but the fact that I cannot do anything with the antennas and the interference put me off.
I mean... you could go buy or build an antenna appropriate for the signal you want to monitor? If you've got the space for it, a wideband discone like this one [1] out on the balcony and up on your roof paired with a wideband LNA from Mini-Circuits will give you acceptable reception from low VHF all the way up through S-band. Or, if you are looking for a specific frequency, build yourself a dipole of the correct length (it's really not hard).
You can't cheat physics, you do in fact need the right antenna. I don't know what else to tell you.
I either had a terrible antenna, interference or reception at my apartment and so my dongle gathered dust for a few years until I camr across an Android SDR Touch app. Using a USB-OTG I could easily listen in on the go for cheap.
For some values of "those" yes, for others No. Some are receivers that can only receive but you can also get transmitters or transceivers that will do both. Most of the cheap dongles are receive only. Disclaimer: Your local laws regarding the legality of transmitting (or even receiving) on a particular frequency at any given power may vary.
Receiving radio is perfectly fine and you aren't at risk of interfering with anyone.
Transmiting is very "dangerous" if you don't know what you're doing, and likely illegal unless you're licensed (you're only allowed to broadcast on certain frequencies below certain power limits without a license, but you can still cause trouble).
Tl;Dr Please do not experiment with transmitting if you don't know what you're doing.
Even more pedantic: There is an exception to the broadcasting rule.
>Communications directly related to the immediate safety of human life or the protection of property may be provided by amateur stations to broadcasters for dissemination to the public where no other means of communication is reasonably available before or at the time of the event.
Whatever you do, PLEASE PLEASE PLEASE DO NOT TRANSMIT BETWEEN 1.100 Ghz and 1.600 Ghz. GPS receivers operate on very low power signals and it's entirely possible to accidentally jam them even without high power signals. If you are near the approach path for an airport you can cause serious problems.
Or if you use them, do so in a completely RF shielded environment. You wouldn't want to wreck havok with drones, Lime scooters, Bird Scooters, cell phones, etc. Right? :)
Yeah that ia definitely one no to stomp on. Vls an tacan are good ones too but they are immediately apparent if you stare at the band. Gps is so quiet you would only know by looking it up. Which you should absolutely do before TXing.
Is the system different for Civilians? It seems like a system that is so fragile would be a pretty big vulnerability for something that is in such high use by the Military.
The military has a higher bitrate (and encrypted) signal, which leads to higher positional accuracy if you have the code. It's no less vulnerable to brute force jamming though, which is why military platforms typically solve this by having GPS receivers with high receive selectivity upwards and very low selectivity in the horizontal plane (where hostile platforms carrying jammers are likely to be).
Source: studied weapons engineering in Naval College.
The military does not have a different system, though - at least in the past, not sure how things are now - they had access to different modes of precision, and it is possible to augment GPS by using ground based reference beacons if you want.
As for the signal levels at the antenna, that is just a function of distance of the transmitters and the crappy antenna on the receivers. The fragility is to some extent overcome by using multiple satellites (more than you need a fix for), but of course these can still be overcome by a jammer.
If you really want a stronger signal you have a couple of options, the first one would be a better antenna, the second to chill the receiver pre-amp.
The best analogy is to imagine someone who is 100 yards away from you shouting at the top of their lungs and then someone who is whispering up close straight in your ear. That's just the physics side of it and no amount of trickery is going to change that in a way that will make the system more robust against jammers. Any radio based system can be jammed like that.
It's also illegal to transmit unlicensed in the L band. Fortunately though, GPS uses spread spectrum signals which are incredibly resistant to interference, in addition to using several frequencies simultaneously and several reference recievers on the ground, it is extremely unlikely you will jam GPS.
Also don't stomp on ham bands even if they appear empty. They are almost universally awesome people. There are emergency channels, that should fall under "look up what the band is for" but, idiots...
This isn't about authority. This is about being mindful of a scarce shared resource to prevent the tragedy of the commons - and what you said about power etc is not universally true.
For various reasons (such as, it can cause interference), I do not want to transmit, and would rather have one that cannot transmit or that has a hardware switch to disable transmitting when you do not want to transmit.
+1 on this one: well built, optimized for small signal reception (TV dongles are not) therefore lower noise etc. bias tee for active antennas, metal case. Still at a good price. I have two of them and never regretted the purchase.
One day I'l probably get a HackRF or something similar, although I'm still good with the rtl-sdr.com dongles. If they made a small one with enclosed upconverter to be put in my laptop bag to be carried when I take a trip in the mountains I'd get one immediately. I've tried one of those no-name Chinese little boxes with HF and V-U inputs but performance is inferior compared to the above dongle.
Are there any cheap upconverters that will make use of its insane bandwidth? I'd like being able to receive down to the HF but the Pluto doesn't go below 325MHz.
My advice would be the same. These units are mostly built on the same parts, the big difference is build quality (metal dongle vs plastic) and what antenna comes bundled (antenna quality/size matters a lot for anything beyond just tinkering).
It's more than just build-quality. The actual RF design is very different. The RTL-SDR V3 dongle was purpose built to be an SDR device. Most of the generic plastic dongles were designed to watch broadcast television.
I recently got a couple of the NooElec NESDR SMArt v4 dongles, and I've been quite happy with them. I also have a few no-name dongles, with one of them that has been running rtl_433 for years now to graph outdoor and basement temperature and humidity from off-the-shelf sensor units.
The NESDRs are much more accurate than the no-names and don't drift. I was flabbergasted when I plugged one in, tuned it to a nearby NOAA weather transmitter, fired up gqrx, and saw that it was spot-on without having to adjust the frequency error. Also, they have SMA connectors instead of the dodgy barrel connectors on the no-names.
Just hop on Amazon and search for rtl-sdr dongle. AFAIK they're all roughly the same since they're based off the same hardware; any with decent reviews should be fine. I think mine was a Nooelec brand or something; comes with the dongle and an telescoping antenna.
