Software Defined Radio
Question: Do you want to …
- use SDR at a system level, to learn and just receive RF signals. SKIP to PART 2
- build the fundamental knowledge in rf theory, design, and implement the complete physical layers for digital communications systems. READ ON.
Stay tuned… the wireless revolution is just beginning!
RTL-SDR
It’s advertised as, ‘a device costing less than $20 for EE students, professional engineers, makers and hackers alike to acquire and samle RF (radio frequency) signals tranmitted in the frequency range 25MHz to 1.75GHz.’
Signals the hardware can receive
- FM radio 87.5 - 108 MHz
- Aeronautical 108 - 117 MHz
- Meteorological ~ 137 MHz
- Fixed mobile 140 - 150 MHz
- Special events broadcast 174 - 217 MHz
- Fixed mobile (space - earth) 267 - 272 MHz
- Fixed mobile (earth - space) 213 - 315 MHz
- ISM band (short range) ~433 MHz
- Emergency services 450 - 470 MHz
- UHF TV Broadcasting 470 - 790 MHz
- 4G LTE 800 MHz
- SDR / IoT 863 - 870 MHz
- Smart Meters (rflan) 902 - 928 MHz
- GSM 921 - 925 MHz
- GPS 1227 - 1575 MHz
Fundamental theory and background in Digital Signal Processing (DSP)
- The Nyquist sampling theorem and time domain signal representation;
- The frequency domain, or spectral representation of signals using DFTs andd FFTs;
- Basic design and implementation parameters of filtering, digital filters and multirate;
- The generics of the radio frequency (RF) spectrum and using an antenna to receive RF signals.
MATLAB & Simulink
Technical Talks
SCaLE 2019 - Helping fire fighters
Softwares
Useful tools
- conversion for inch / centimeter
- everythingRF calcs
- desktopSDR.com
Hardware
RTL-SDR
Receiving frequencies ranging from 25Mhz to 1.75GHz. The IC is a 6mm square chip (COQFN) coded orthogonal frequency-division multiplexing demodulator. It supports tuners at IF, low-IF, and zero-IF. It was made to handle compressed MGEG2, MPEG4 transport streams.
Test mode
It can be placed into a test mode which it then acts as IF digital radio. Essentially becoming a high speed ADC. The output is raw quadrature data with an 8-bit resolution.
The most common tuner is Rafael Micro R820T.
Working with a suitable antenna
Antenna gain is a term used to describe how much more power can be transmitted or received with a particular antenna than could be with losslss istropic antenna. It is measure in dBi, which refers to decibles over the isotropic. Antennas emit electromagnetic waves with different radiation patterns.
Omni directional vs Directional
The isotropic antenna radiates waves uniformly in all directions, so it has a directivity of zero. Directional antennas radiate mainly in one direction with a higher gain.
Tuned antennas
Tuned antennas as designed to resonate and receive particular bands of electromagnetic waves, meaning they have a high antenna gain for these intedned frequencies, and low gain for all others.
Antenna polarisationand positioning
Signals can either be transmitted as lineraly polarised (meaning they are transmitted in one plane) often horizontally or vertically. Or transmitted with a circular polarisation (meaning they are transmitted in two planes as a helix).
Cell phones
iPhone test mode
- Turn off WiFi
- Dial 3001#12345#
- Press the call button
- Field test mode menu will show up
US Carrier Frequencies and Bands
| Carrier | 4G LTE bands | Main frequencies |
|---|---|---|
| AT&T | 2, 4, 5, 12, 14, 17, 29, 30, 65 | 1900, 1700 abcde, 700bc |
| Verizon Wireless | 2, 4, 5, 13, 46, 48, 66 | 1900, 1700 f, 700 c |
| T-Mobile | 2, 4, 5, 12, 66, 71 | 1900, 1700 def, 700 a, 600 |
| Sprint | 25, 26, 41 | 2500, 1900 g, 850 |
CDMA vs GSM
There are two radio networks used by wireless carriers and present in cell phones. CDMA stands for “code division multiple access”. GSM stands for “global system for mobiles”.
In the U.S., carriers operating on GSM frequencies include T-Mobile and AT&T. Sprint and Verizon are CDMA carriers.
US Carriers
Verizon
| Carrier | 3G | 4G | 5G | |–:|:-:|:–|—| |Verizon| CMDA 800, 1900 PCS | 2, 4, 5, 13*, 66 | |
| AT&T | GSMA/HSPA/HSPA+ 1900, 850 | 2, 4, 5, 12, 14, 17, 29, 30, 66 |
| Carrier | 3G | 4G | 5G |
|---|---|---|---|
| TMobile | GSM/HSPA/HSPA+ 1900, 1700, 2100 | 2, 4, 5, 12, 66, 71 | |
| Sprint | CDMA 800, 1900 | 25*, 26, 41 |
5G Frequencies that can provide 5G Band n71 (600 MHz) Band n41 (2.5 GHz) Band n260 (39 GHz) Band n261 (28 GHz)
Extended Range 4G LTE Band 12 (700 MHz) Band 71 (600 MHz)
4G LTE Band 2 (1900 MHz) Band 5 (850 MHz) Band 4 (1700/2100MHz) Band 66 (Extension of band 4 on 1700/2100 MHz)
3G (UMTS/HSPA) Band 4 (1700/2100 MHz) Band 2 (1900 MHz)
2G (GSM, GPRS, EDGE) Band 2 (1900 MHz)
- bolded channel are carrier’s main band. ~ August 2020
Amazon order
Dipole set includes 1x dipole base with 60cm RG174,
2x 23cm to 1m telescopic antenna, 2x 5cm to 13cm telescopic antenna,
1x 3m RG173 extension cable, 1x flex tripod mount, 1x suction cup mount.
applications including: general radio scanning, air traffic control, public safety radio, ADSB, ACARS, trunked radio, P25 digital voice, POCSAG, weather balloons, APRS, NOAA APT weather satellites, radio astronomy, meteor scatter monitoring, DAB, or for use as a low cost panadapter with a traditional ham radio. Several improvements over other brands including use of the R820T2 tuner, improved component tolerances, a 1 PPM temperature compensated oscillator (TCXO), SMA F connector, aluminium shielded case with thermal pad for passive cooling, activatable bias tee circuit and a much improved antenna set.
Can tune from 500 kHz to 1.7 GHz and has up to 3.2 MHz of instantaneous bandwidth (2.4 MHz stable).
(HF reception below 24 MHz in direct sampling mode with reduced performance). Please note RTL-SDR dongles are RX only.
https://www.nuand.com/bladerf-2-0-micro/
https://www.nuand.com/product/bladerf-xa4/
Westinghouse Outdoor 3 Outlet Wireless Photocell Item #91171 | Model #RT304
LM 6.7458MHz crystal
| Westinghouse Radio Transmitter | Model #WK262 |
Home power meter consumption
https://www.rtl-sdr.com/monitoring-home-power-consumption-with-an-rtl-sdr/
Open Source Mobile Communications
P25
broadcastify feed with sdrtrunk
SDRTrunk P25 police scanner with two rtl-srd
Pager system
https://www.youtube.com/watch?v=wI0bfKnlu8M
POCSAG
Aerospace
to translate knot to miles per hour, multiply the speed value by 1.151
200 kt = 230.156 400 kt = 460.312
Ground speed is self explanatory, it’s the time it takes you to cover a certain distance over the ground. When at their cruise altitude, aeroplanes might have a ground speed anywhere between 300 – 600 nautical miles per hour. Whilst they usually cruise at the same airspeed, the wind can make a big difference to the speed at which the aircraft passes over the ground. A tailwind pushes the aircraft along whilst a headwind slows the aircraft down.
Airspeed has a few different variations. If an aircraft is sat still on the runway and has a 20 mph headwind, the aircraft already has an airspeed of 20 mph, despite the fact it isn’t actually moving. This is because airspeed is a measure of the speed of the air over the wing. The speed of the air travelling over the wing dictates how much lift the wing is producing, and it’s this lift that allows the aircraft to support its own weight and allows it to fly.
If an aircraft has a take off speed of 140 mph, but has a 20 mph headwind, the aircraft will only need to achieve a 120 mph ground speed before it is able to take off. Conversely, if an aircraft has a 20 mph tail wind, it would need to achieve a 160 mph ground speed in order to lift off the ground.
Pilots always make reference their airspeed rather than ground speed as it is the airspeed that keeps the aircraft flying. The groundspeed is a byproduct. In principle, if you had about a 140 mph headwind the aircraft could lift off the ground without moving forward!
adsb exchange [flightradar24 - LAX ]https://www.flightradar24.com/33.95,-118.33/10()
Visualizing ADSB data in 3D using MATLAB
small rf
Recovering 433MHz messages with RTLSDR and MATLAB
hydrogen line radio telescope
WVU - DSP in Radio Astronomy resources WVU - DSP in RA classroom wvu project documentation
simple observations of 21cm hyrdrogen line emission
as dr seti - what is hyrdogen line
track milkway movement diy pyramidal horn antenna
Meteor scatter
Project Loon - callsign HBALxxx
NOAA
NOAA NCEP Data Collection Platforms
NOAA Weather station map California
emergency management
Responding to natural disasters p1
conference talk - responding to natural disasters description
SCaLE - responding to natural disasters