Ambientscape WebSDR

'Listen to Live Radio Transmissions from Earth and Space'

Based in Harrow the Ambientscape WebSDR is a radio receiver comprised of a Nooelec RTL-SDR, SDRplay and HackRF Software-Defined Radio from a mobile Receive Only Earth Ground Station. It runs on a low power reused Raspberry Pi server with a solar panel and renewable battery backup. This WebSDR is intended to be an educational tool for those that may have an interest in amateur radio or satellite communication.

Radio is a mode for transmitting and receiving electromagnetic waves of radio frequencies especially those carrying sound messages. Software-Defined Radio (SDR) is a radio communication system where components that have been implemented in earlier analog hardware e.g. amplifiers, mixers, filters, modulators/demodulators are instead implemented by means of software on a computer or embedded system which performs the radio signalling process.

A WebSDR is a Software-Defined Radio Receiver connected to the internet which allows many users to listen to and tune a radio simultaneously. The WebSDR provides listeners with a way of hearing or recording radio audio signals through antennas based at the Ambientscape Crystal Radio Receiver Earth Station and to experience the method of tuning a receiver using software.

The Software Defined Radio is popular in the field of radio astronomy where it can be utilised as a radio telescope together with suitable antennas, low-noise amplifiers and filters to detect phenomena such as hydrogen line emissions in the Milky Way and meteor scatter.

The Ambientscape WebSDR may be used to capture experimental live radio sound effects during frequency shifting, modulation or filtering, scanning VHF/HF/UHF to listen to Ham radio operators, aviation pilots, decoding data, hearing the odd world music station and to receive voice transmissions, packet messages or SSTV images from the ISS (International Space Station).

Downlink data from the African GaindeSat and Djibouti nanosatellites can also be heard for Earth Observation (EO). Sound does not travel in space and so encoded radio waves are used for communicating between the transmitter and receiver. The WebSDR receives the radio waves as audio where it can be recorded and decoded later on with software and finally archived making it a useful instrument in the preservation of audio (sound) data.

Communication between aviation pilots and air traffic control can also be heard on the Airband VHF frequency where audio speech messages or live decoding of data can be done in real time.

SDR Devices: Nooelec RTL-SDR, x2 SDRplay, HackRF

Web Server: Raspberry Pi 4 Model B

Software: OpenWebRX+ Web Based SDR Receiver in Linux Debian OS

Antenna Models: Sirio 1/4 Wave Ground Plane, SPX-100 Helical, Scan King Discone, Magnetic Longwire Balun, Yagi YG27-35

Scanning Modes, SDRs and Antennas:

2M Band ISS (VHF) 143.980 MHz to 146.020 MHz (SDRplay 1) Discone and yagi antennas on splitter

20M Band (HF) 13.131 MHz to 15.221 MHz (HackRF), 9:1 Magnetic end fed longwire balun in a tree

40M Band (HF) 6.127 MHz to 8.167 MHz (Nooelec SDR) Portable vertical helical telescopic antenna

Space Satellites (UHF) 399 MHz to 402MHz (SDRplay 2) Yagi and satellite tracking antenna rotator

Airband (VHF) Aeronautic 134.978 to 137.0191 (Nooelec SDR) 1/4 wave ground plane antenna

Click to run the Ambientscape WebSDR through your web browser

Read instructions on how to use the OpenWebRX+ web based software on the Ambientscape WebSDR

What is the ISS?

The I.S.S. International Space Staion is a large, Low Earth Orbiting (LEO) spacecraft and home to a crew of astronauts and cosmonauts. It orbits the Earth at a height of 250 miles, 16 times a day, at a speed of 28,000 km/h and is the largest orbiting laboratory and observatory for scientific research. The ISS is used for researching space technology and a platform for STEM education.

As of October 2024 there are 10 astronauts in space:

International Space Station, Starliner CFT - Butch Wilmore, Sunita Williams

International Space Station, SOYUZ MS-26 - Don Pettit, Alexey Ovchinin, Ivan Vagner

International Space Station, SpaceX Crew-9 - Nick Hague, Aleksandr Gorbunov

Tiangong Space Station, Shenzhou 19 - Cai Xuzhe, Song Lingdong, Wang Haoze

Listen to Astronauts from the ISS International Space Station

Step 1: Locate the ISS Satellite

Track passing satellite with AMSAT Online Satellite Pass Predictor using the coordinates below

Station Coordinates:

Latitude: 51.585

Longitude: -0.354

Elevation: 53

Result Acronyms

(UTC) = Coordinated Universal Time

(AOS) = Acquisition of Signal

(LOS) = Loss of Signal

Click to Convert (UTC) time zone to your local country time zone using the calculator

(UTC) + 0 is the default timezone used by the AMSAT Pass Predictor for United Kingdom, Iceland,

Ghana, Senegal and Mali (corresponding with GMT, Greenwich Mean Time)

Step 2: Tune SDR to Correct Frequency

Hear the ISS

Tune the Ambientscape WebSDR for 2M, SDRplay on 145.800 MHz to hear ISS voice transmissions

Receive Messages

Tune the Ambientscape WebSDR for 2M, SDRplay on 145.825 MHz to receive ISS APRS messages and

Click on the yellow (ISS APRS Packet Messages) bookmark in the Ambientscape WebSDR to decode

Wait for next predicted pass overhead using timings from Online Satellite Pass Predictor

* Our stationary yagi antenna is pointed towards the sky above the earth station with a clear line of sight

Other Considerations:

Range, Schedule and Signal

* ISS is in range 5-6 times a day for a maximum of 10 mins, transmission schedules vary and signal may be faint

* It is also quite normal not to hear anything during a pass in which case you can still pick up APRS messages from the ISS

Doppler Effect

When the ISS is approaching transmit frequency of 145.800 may appear 3.5KHz higher

(145.8035), as the ISS moves out of range the frequency will then shift down to 145.7965,

Ambientscape WebSDR can be tuned to follow and compensate for the changes

(Optional) SSTV Audio to Image Decoding

Tune the Ambientscape WebSDR for 2M, SDRplay on 145.800 MHz to hear SSTV data audio tones or

Click on the yellow (ISS SSTV) bookmark in the Ambientscape WebSDR to decode SSTV audio to images

The Importance of African Space Satellites

We have an interest in monitoring African satellites that are used for the good of the environment to better understand our world.

There are at least 26 satellites orbiting the Earth from the African continent including those deployed to monitor the environment, assessing agricultural yields, checking water/air quality, observing the weather climate, tracing forest health and preventing illegal mining. Satellites includes the GaindeSat-1A and Djibouti-1A.

GaindeSat-1A

Senegal launched its first satellite on the 16th August 2024 at 7.56pm BST. The nanosatellite was built over the course of 3 years by Senegalese engineers and technicians with the latter trained at Centre Spatial Universitaire Montpellier in partnership with the Senegal government. GaindeSat

is a (LEO) Earth observation satellite for environmental data gathering in particular water resources weather forecasting and the monitoring of Senegal's lakes and watercourses.

Djibouti-1A

Launched on November 11th 2023 Djibouti-1A is the first satellite from the Republic of Djibouti, the 1U CubeSat is designed by Djiboutian students from the University of Montpellier Space Station and is used to track environmental changes from climatological, rainfall and limnimetric stations spread across the Djiboutian territory.

Djibouti-1B

Djibouti 1B is the second satellite from the Republic of Djibouti launched on the 21st December 2024. The mission of the CubeSat is data collection from climatological, rainfall and limnometric sources.

Yam-Sat CI-01

Ivory Coast's first satellite is scheduled to be launched in 2025 and will be used for monitoring deforestation, soil humidity and water reservoirs.

Receive Transmitted Data Audio from GaindeSat-1A

Tune the SDR to Correct Frequency of GaindeSat-1A Satellite

Tune the Ambientscape WebSDR for Satellites SDRplay (2) UHF on 401.800 MHz or

Click on the yellow (GaindeSat / Djibouti Satellites) bookmark in the Ambientscape WebSDR

(Currently Testing)

Receive Transmitted Data Audio from Djibouti-1A and 1B Satellite

Tune the Ambientscape WebSDR for (Satellites) SDRplay (2) UHF on 401.800 MHz or

Click on the yellow (GaindeSat / Djibouti Satellites) bookmark in the Ambientscape WebSDR

(Currently Testing)

Satellites are tracked with an Antrunner antenna rotator and Gpredict in real time

* Signal strength is weaker due to the size of nanosatellite and dependant on the distance of satellite to antenna

Current Status for Space Satellites as Reported by Users:

View AMSAT Live Oscar Satellite Status

View GaindeSat-1A Observational Log

View GaindeSat-1A Satellite Orbit Data

View Djibouti-1A Observational Log

View Djibouti-1B Observational Log

The Crystal Radio Receiver Earth Station @ Satnogs Network

Aeronautic and Aviation Communication

Communication between aircraft pilots and air traffic control can be listened to and messages decoded in real time using the WebSDR. Aircraft are identified with different IDs including the aircraft tail number and ICAO code.

Voice

Tune the Ambientscape WebSDR and select the (Airband) option to find audio voice transmissions

Messages

Click on the (SITA-Europe 1), (SITA-Europe 2), ARINC-Europe 1), (ARINC-Europe 2), or (SITA & ARINC-Worldwide) yellow bookmarks at the top right of the screen on the (Airband) option in the Ambientscape WebSDR to begin decoding flight messages

Further Links

Current Position of ISS

The Radio Society of Harrow

OMIK Amateur Radio Association

NASA's African American Astronauts

List of African Countries with Satellites

The Society of Amateur Radio Astronomers

The Latest Status of ISS HAM Radio Stations