Chasing Waterfalls: Exploring the airwaves with RTL-SDR
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RTL-SDR & Software-Defined Radios
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My Minnebar 9 / 2014 talk about RTL-SDR Video of talk at https://www.youtube.com/watch?v=N2u3Qu1dhAs
Transcript of Chasing Waterfalls: Exploring the airwaves with RTL-SDR
RTL-SDR & Software-Defined
Radios
I'm a radio nerd.
N0RUA
1/5/2013 / ZD7FT / St. Helena Island (6,866 mi)
2/23/2014 / RX0AK / Asiatic Russia / 5,460 mi
Public Service
Cool experiments
It's all around us!
It's all around us!• AM/FM audio broadcast
It's all around us!• AM/FM audio broadcast
• TV broadcast
It's all around us!• AM/FM audio broadcast
• TV broadcast
• Cell phones, wifi
It's all around us!• AM/FM audio broadcast
• TV broadcast
• Cell phones, wifi
• Bluetooth, etc.
It's all around us!• AM/FM audio broadcast
• TV broadcast
• Cell phones, wifi
• Bluetooth, etc.
• But...
How does it work??
Components
Componentstransducer
Componentstransducer
Componentstransducer
Componentstransducer
Componentstransducer
Oh yeah, the antenna goes here.
Componentstransducer
Electromagnetic Radiation aka!~~~ Radio Waves ~~~
Direction of travel
Wavelength
Wavelength
Wavelength
Wavelength
Frequency
Hertz = Hz = Cycles per second
Time!(sec)
1 2 3
Time!(sec)
1 2 3
f = 1 Hz
Time!(sec)
1 2 3
f = ~ 4 Hz
Time!(sec)
1 2 3
Higher Frequency = Shorter Wavelength
A little math... (I'M REALLY SORRY)
velocityfrequencyλ =
velocityλ
frequency =
the speed of light (c)
frequency (Hz)λ (m) =
300,000,000 m/secf(Hz)
λ (m) =
λ (m) = 300,000,00089,300,000
λ (m) = 300,000,00089,300,000
30089.3
λ (m) = 300,000,00089,300,000
30089.3
3.35 m~11 ft
30089.3
3.35 m
3002400
.125 m~11 ft ~ 4.9 in
30089.3
3.35 m
30014.2
21.1 m
3002400
.125 m~11 ft~69 ft ~ 4.9 in
Enough of that..
3 kHz - 300 GHz
Radio spectrum
λ = 100 km - 1 mm
Radio spectrum
AM Broadcast!~ 530 - 1700 kHz = 1170 kHz bandwidth
FM Broadcast!87.5 - 108 MHz
= 20.5 MHz bandwidth
Wi-Fi/etc!2.4 - 2.5 GHz = 100 MHz bandwidth
Modulation
= encoding information in a signal
beeeeeep beep beeeeeep
K
beeeeeep beep beeeeeep
AM
FM
Propagation
Line of Sight
Groundwave
Skywave
Ionosphere60 - 500 km altitude
IonosphereDay
"D" Layer
IonosphereDay
"E" Layer
IonosphereDay
"F1" Layer
IonosphereDay
"F2" Layer
IonosphereDay
IonosphereDay
Ionosphere
F Layer
E Layer
Night
F Layer
E Layer
F Layer
E Layer
F Layer
E Layer
Maximum Usable Frequency (MUF)
F Layer
E Layer
skip distance
Auroral
Meteor Scatter
What's out there?
WTF's out there?HF/Shortwave
WTF's out there?HF/Shortwave
• Broadcasters (AM / Shortwave)
WTF's out there?HF/Shortwave
• Broadcasters (AM / Shortwave)
• Hams
WTF's out there?HF/Shortwave
• Broadcasters (AM / Shortwave)
• Hams
• Gov't Agencies (US or otherwise)
WTF's out there?HF/Shortwave
• Broadcasters (AM / Shortwave)
• Hams
• Gov't Agencies (US or otherwise)
• WEFAX, other data & telemetry
WTF's out there?HF/Shortwave
• Broadcasters (AM / Shortwave)
• Hams
• Gov't Agencies (US or otherwise)
• WEFAX, other data & telemetry
• "Numbers stations"
WTF's out there?HF/Shortwave
• Broadcasters (AM / Shortwave)
• Hams
• Gov't Agencies (US or otherwise)
• WEFAX, other data & telemetry
• "Numbers stations"
• Pirates
WTF's out there?HF/Shortwave
• Broadcasters (AM / Shortwave)
• Hams
• Gov't Agencies (US or otherwise)
• WEFAX, other data & telemetry
• "Numbers stations"
• Pirates
• Lots more!
WTF's out there?VHF/UHF & beyond
WTF's out there?VHF/UHF & beyond
• FM Broadcast
WTF's out there?VHF/UHF & beyond
• FM Broadcast
• Hams
WTF's out there?VHF/UHF & beyond
• FM Broadcast
• Hams
• Fire/Police/EMC/Mall Cops
WTF's out there?VHF/UHF & beyond
• FM Broadcast
• Hams
• Fire/Police/EMC/Mall Cops
• Airport/ATC/ADS-B
WTF's out there?VHF/UHF & beyond
• FM Broadcast
• Hams
• Fire/Police/EMC/Mall Cops
• Airport/ATC/ADS-B
• Pagers & other text (Taxi Dispatch)
WTF's out there?VHF/UHF & beyond
• FM Broadcast
• Hams
• Fire/Police/EMC/Mall Cops
• Airport/ATC/ADS-B
• Pagers & other text (Taxi Dispatch)
• Baby monitors
WTF's out there?VHF/UHF & beyond
• FM Broadcast
• Hams
• Fire/Police/EMC/Mall Cops
• Airport/ATC/ADS-B
• Pagers & other text (Taxi Dispatch)
• Baby monitors
• FUN stuff in the 433 MHz band (unlicensed)
Software-Defined Radios
RTL-SDR
So what?
So what?• Hobby
So what?• Hobby
• Experimentation
So what?• Hobby
• Experimentation
• Public Service
So what?• Hobby
• Experimentation
• Public Service
• Cool Gear ;)
Actual stuff you can do
Detecting the galactic plane with an SDR
rtl-sdr.com
Let's listen to some radio!
