Is anyone into that?
rtl-sdr dongle:
https://hackaday.com/2019/07/31/rtl-sdr-seven-years-later/
https://www.rtl-sdr.com/about-rtl-sdr/
hacking the coffee machine:
http://blog.rona.fr/post/2017/10/15/Sniffing-and-decoding-NFC-with-a-DVB-T-stick-rtl-sdr-and-GNURadio
DSP course where in the final project students are asked to send images using a Baofeng UV-5R and receive them with an RTL-SDR:
https://inst.eecs.berkeley.edu/~ee123/sp16/index.html
Don't do that if you're not licensed. Please.
Don't do that if you're not licensed. Please.
You don't need a license to listen, and there are pretty large parts of the spectrum dedicated to consumer electronics that you can broadcast on below a certain power level.
>>4
If you want to transmit, there are not so many free frequencies, especially for transmitting data.
There's PMR443 and 2.4 GHz or 5 GHz (wifi, Zigbee..). The 900 MHz band that allows longer distance is only allocated to radio amateurs in Region 2 (in Europe it's used for mobile phones)
This is what I want to do:
https://www.youtube.com/watch?v=2TZGzXReN-U
https://www.youtube.com/watch?v=sHGUuGvB0pg
There's a seller on ebay who has ready-made device like the one used in that Berkeley course to connect a Baofeng radio to a computer: https://www.ebay.com/itm/EASY-DIGI-UV-5R-INTERFACE-for-laptops-and-desktops/323006664493
>>5
Alternatively, it's possible to make a much cheaper cable that will not use the VOX feature of the radio. One just need to press the PTT button during transmission:
http://www.highonsolder.com/ham-radio/boafeng-uv5r-usb-soundcard-interface/
http://www.panoradio-sdr.de/tdoa-transmitter-localization-with-rtl-sdrs/
>>7
That's how you play bunny hunting.
https://en.wikipedia.org/wiki/Transmitter_hunting
You can build a passive radar with two cheap rtl-sdr dongles. That's probably how the Serbs downed that F-117 back in 1999.
https://dopplerfish.com/passive-radar/
https://hackaday.com/2015/06/05/building-your-own-sdr-based-passive-radar-on-a-shoestring/
https://www.rtl-sdr.com/building-a-passive-radar-system-with-an-rtl-sdr/
https://www.rtl-sdr.com/passive-radar-dual-coherent-channel-rtl-sdr/
This modification essentially involves using the same clock source for two RTL-SDR dongles, which can be done by desoldering and removing the clock on one dongle, and then using a cable to connect the clock from another dongle to the clock input of the desoldered dongle.
>>9
I wonder if it would be possible with an array of SDRs like the XYNC and RF amps to make an AESA radar with a reasonable resolution.
>>10
I can't tell but there are plenty of fun little things to do with a cheap rtl-sdr dongle like spectrum analyzis or spying on your neighbors keystrokes
http://www.tomsguide.com/us/usb-tv-tuner-software-defined-radio-sdr-radio-spying-privacy,review-1836.html
https://thedorkweb.substack.com/p/youre-almost-entirely-blind
The ultimate radio device was the Mattel Radica Girltech IM ME, a $12 pink toy pager that some hacker bought as a filler item on Amazon
https://web.archive.org/web/20111204042145/http://www.hunterdavis.com/archives/333
It's been used as a spectrum analyzer, a jammer for police radio communications, a sesame to open garage doors... Mattel doesn't produce them anymore and they go for insane prices on ebay today.
http://samy.pl/opensesame/
http://travisgoodspeed.blogspot.com/search/label/imme
If you want a SDR receiver (Rx only) that doesn't require a Ham license, you can buy either DX Patrol or RTL-SDR v4 (or v3). Both should work on GNU/Linux with gqrx (on Windoze, you probably need SDR# aka SDR Sharp). But pls note that there are a ton of counterfeit clones of the RTL-SDR. You should buy it from the Ebay link in the official RTL-SDR site (included in OP).
If you have a Ham license, you can buy a QUANSHENG UV-K6 (or UV-K5) walkie-talkie. Then install the IJV firmware via the programming cable (make sure that the package you buy will include the programming cable!). The homebrew firmware basically unlocks the radio and add some nice goodies. I heard that the stock antenna is very bad, so don't use it for transmitting without testing it with antenna analyzer (ask at a local Ham club). If you want a portable radio transceiver with okay antenna, you should buy Baofeng UV-82 or Wouxun KG-UV6D but note that you can't unlock the radio on these models (you need to have QUANSHENG UV-K6 or UV-K5). If you want, you can build a J-stick antenna relatively easily. You want to reference ARRL Antenna Book, ARRL Handbook and Cebik antenna collection. You can also use 4nec2 software for simulating how your antenna works.
If you don't want to spend any money, you can use WebSDR to listen to radio transmissions. There are free servers in many locations over the world.
Useful links
* PSK reporter: https://pskreporter.info/pskmap.html
* DX Summit (see who is calling CQ): http://www.dxsummit.fi
* Learn cw (morse code) for free: https://lcwo.net (you really want to use the Koch Method!!)
* ... Here is another good program for learning cw but note that it's proprietary freeware: https://www.g4fon.net/CW%20Trainer2.php
* Space weather (1): https://www.hamqsl.com/solar.html
* Space weather (2): https://www.swpc.noaa.gov (more: https://soho.nascom.nasa.gov/spaceweather/)
* Callsign DB (doesn't list all), Hams often put info about their setups on their page: qrz.com
* ClubLog: https://clublog.org/logsearch.php
* Find software packages: https://www.debian.org/blends/hamradio/ && https://wiki.debian.org/DebianHams
* ... More: https://github.com/DD5HT/awesome-hamradio
* ... More: https://en.wikipedia.org/wiki/List_of_amateur_radio_software
* https://wiki.gnuradio.org/index.php/Hardware
* Q Codes (you don't need to learn all of these!): https://en.wikipedia.org/wiki/Q_code
* Morse code abbreviations: https://en.wikipedia.org/wiki/Morse_code_abbreviations
* the ICAO/ITU/"NATO" Phonetic Alphabet: https://en.wikipedia.org/wiki/NATO_phonetic_alphabet#Tables_2 (You want to learn the latest version that has A = Alfa, etc.)
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