If you want to dabble for _cheap_ with SDR, the RTL-SDR [1] is a < $10 USB receiver that works from 24 to 1766 MHz.
It allows to listen to FM radio, decode most 433MHz devices (weather stations), car keys signals, and even NOAA weather satellites [2] with a DIY antenna [3].
You can also track your neighbors' energy usage by decoding their smart meter transmissions (around here, they transmit about every minute). https://github.com/bemasher/rtlamr
I can read about 40 smart meters from inside my home using the antenna that comes with it.
Said from experience of having built something more complicated and having it perform worse than two pieces of copper tubing stuck in a piece of scrap plastic.
I've been dabbling with RF, but I don't quite understanding the appeal of downloading NOAA sat images. It is simply 'hello world' for receiving sat downlinks?
As an aviation enthusiast, I've got a Raspberry Pi in my attic hooked up to two RTL-SDR radios, each connected to homemade antennas mounted on my roof (one VHF to listen to airband transmissions and the other receiving ADS-B[1]). No signal processing required--both are pretty easily achieved by just cobbling together existing open source packages. Also have a GPS receiver on the roof so that Raspberry Pi is also a stratum-1 NTP time server[2]. But that one's not using an SDR. Fun hobby.
EDIT: Added links I found helpful, for the curious:
Can you suggest something that could be used to read or reprogram wireless access cards, such as the HID Proxcard II? I want to clone my apartment's key fob into a bracelet I can wear when I go jogging.
Clarification for the audience: "RFID" has very little to do with radio or SDR. Communications are done with a coil in the "near field", which also powers the tag.
For what it's worth, Great Scott Gadgets (Michael Ossman's group) put out a great series of primers [1] on Software Defined Radio (SDR) and the fundamentals of Digital Signal Processing (DSP) a while back, that are some of the best I've seen out there to date.
Not at _all_ surprised to see Balint Seeber's name prominently in some of those links...
That guy gives some _amazingly_ interesting talks - I got into SDR pretty much purely based on a presentation of his at DorkBot in Sydney a long time back...
Thanks for posting links to the videos and the meetup group, would've joined it years ago if I'd known about it. Quick question, anything radar related in the videos?
Anyone know the story behind why baudline hasn't been updated in seven years? The site has promised a beta version with some highly desirable features for a LONG time, but nothing. Also, since it's closed source, there's nothing we can do but hope and wait (unless someone were to start an open source equivalent project).
Virtually every professional radio is software defined to some extent these days, so every company that designs radios wants signal processing and information theory skills, more so if they are doing proprietary protocols rather than implementing a standard. It's pretty well the same skill set, whether you are designing or analysing systems. There is a surprising amount of reverse engineering in building radio systems, as the big players (looking at you Motorola) often drop speed humps into their implemetations to try and break compatability with the smaller players' products.
I am always looking for people with SDR skills :-). Constraint being I need US citizens (naturalized or native) given that the company I'm working for is doing contracts for customers that require that.
BladeRF is pretty cool. It doesn't have quite the frequency range of HackRF, but it's full duplex, and uses 12-bit ADC/DAC (vs. HackRF's 8-bit ones). Also it uses USB 3 so the bandwidth is not limited to 20MHz. (I think it's around 40MHz.)
Analog Devices has done the ADALM-PLUTO which is less expensive than the HackRF-One. I don't have one of those but I do have the HackRF one, and if UPS is to be believed a LimeSDR :-). The cost/capability matrix is sort of
Readit News
It allows to listen to FM radio, decode most 433MHz devices (weather stations), car keys signals, and even NOAA weather satellites [2] with a DIY antenna [3].
[1] https://osmocom.org/projects/sdr/wiki/rtl-sdr
[2] http://www.rtl-sdr.com/rtl-sdr-tutorial-receiving-noaa-weath...
[3] http://tinhatranch.com/how-to-build-a-qfh-quadrifilar-helix-...
I can read about 40 smart meters from inside my home using the antenna that comes with it.
Said from experience of having built something more complicated and having it perform worse than two pieces of copper tubing stuck in a piece of scrap plastic.
EDIT: Added links I found helpful, for the curious:
1: http://www.rtl-sdr.com/adsb-aircraft-radar-with-rtl-sdr/
2: http://www.satsignal.eu/ntp/Raspberry-Pi-NTP.html
[1] https://greatscottgadgets.com/sdr/
[1] https://www.youtube.com/playlist?list=PLPmwwVknVIiXGzKhtimTM...
[1] https://www.meetup.com/en-US/Cyberspectrum/
[2] https://www.meetup.com/en-US/Cyberspectrum-Melbourne/
That guy gives some _amazingly_ interesting talks - I got into SDR pretty much purely based on a presentation of his at DorkBot in Sydney a long time back...
It's a course that relies heavily on MATLAB though.
Deleted Comment
https://news.ycombinator.com/item?id=13101924
It's always nice to see RF and Signal Processing stuff on HN.
Are there any other comparable options?
RTL Dongles -> ADALM -> HackRF-1 -> LimeSDR -> Ettus SRP
The RTL's don't transmit but all of the other ones can.