Table of Contents

transceivers - software defined radio (SDR)

see also:

  • I don't sell any of these nor do I receive any remuneration if you buy them, and I have not personally reviewed all of them, they are listed here to give you perspective

Introduction

  • non-approved radio transmitters are illegal to even POSSESS in Australia
    • its impossible to work out from the legislation if the very low power SDR transceivers outlined here are legal to possess in Australia or not but seems the universities use them for teaching so I presume they are as long as you don't transmit illegally but I'm not confident at all about their legality for possession - see https://www.legislation.gov.au/F2021L00661/latest/text
    • examples of explicitly illegal devices without an approved license include:
      • CB radios above 5W or allow non-permitted transmissions - hence most of the Chinese online 2-way radios are NOT legal in Australia as often they are above 5W, allow transmissions on non-permitted wavelengths and are not certified for use in Australia!
      • mobile phone boosters (but approved cellular mobile repeaters are permitted)
      • WiFi jammers
      • drone jammers
      • mobile phone jammers
      • GPS jammers
  • in Australia, ordinary citizens without a radio license CAN use:
    • 2-way radios up to 5W on the approved CB radio bands for Australia
    • approved radio emitting devices such as:
      • smartphones, computers, tablets, WiFi routers, general WiFi-enabled devices, Bluetooth devices, FlipperZero, etc.
  • if you have a Ham radio license, you can also transmit on Ham radio frequencies in accordance to the rules, and at higher transmission power eg. 10W for foundation licensees
  • SDR transceiver devices generally allow a lot of transmitting mode functions which may be ILLEGAL - the fine in Australia is up to $420,000 and/or 2 years jail!
    • eg. HackRF Portapack does include various functions which are ILLEGAL in many countries including Australia but at the max transmit 32mW power of a HackRF there is not enough power to act as actual radio jammers
    • there are no Filters in the HackRF to limit spurious transmissions and this must be provided by external circuitry - hence these devices may NOT actually be compliant with Australian law even though they are primarily low output devices with max. 3-32mW transmitter power (max. at ~2.4GHz) for lab use1)
  • when using SDRs with transmit capability, to avoid legal issues from illegal transmissions (and minimise device damage):
    • Never transmit on any band on which you are not licensed to operate
      • eg. do NOT transmit ADS-B and POCSAG transmissions or broad transmissions such as jammer function (other than at very low power for lab purposes)
    • Always terminate TX ports with a 50 Ohm load (either an antenna or SMA terminator)
      • this will limit Tx output substantially and should avoid Tx issues
    • Never connect a TX port directly to an RX port without proper attenuation at least 30 dB

The problem with unlicensed transmissions or use of non-approved radio transmitters

Standalone SDR devices with software and GUI

Transceivers requiring a GUI device

HackRF-based transceivers
OpenSource SDRLab B210 clone
Analog Devices AD9363 wideband transceiver SDRs
Analog Devices AD9361 wideband transceiver SDRs
Analog Devices AD9364 wideband transceiver SDRs

Radio signal cloning devices

  • most modern cars and garage roller door systems in the last 20yrs have rolling code technology to prevent simple replay attacks as rolling codes change every time the key fob button is pressed, invalidating any previously captured signal, or they use encrypted systems and thus are immune to these transceiver devices
    • the Flipper Zero community and developers deliberately avoid implementing support for cracking rolling code systems in the device’s official software due to the legal and ethical risks but nefarious actors could potentially create a system
    • HOWEVER, all you need to do to defeat rolling code tech is to use an illegal WiFi jammer (eg. HackRF) at around that frequency so the car does not detect the key fob's signal, then record the key fob signal and then when you turn off the jammer, you get to replay the signal once only to open the car - see https://www.youtube.com/watch?v=pfxo7PhOR_w
1)
https://github.com/portapack-mayhem/mayhem-firmware/wiki/Transmitters
2)
https://www.youtube.com/watch?v=Ew2qDgm2hf0
3)
https://www.youtube.com/watch?v=HLp5dCiy-Oo