Tagged: Radiosonde

A Physical LED Vehicle HUD for KerberosSDR Radio Fox Hunting

Mark Jessop (@vk5qi) has recently been experimenting with a LED based hardware vehicle heads up display (HUD) that he has created to be used together with our KerberosSDR. The KerberosSDR combined with four antennas in a circular array determines the bearing towards a transmitter, and then the HUD displays this bearing visually on a circle.  

The HUD is cleverly designed so that the LEDs reflect on the windshield of the car, allowing for the lights to be safely seen on the windshield while driving. More videos of the HUD being developed and used can be seen on his Twitter feed.

In the video below Mark also shows how he combines KerberosSDR bearing data with his Chase Mapper software, which he uses for tracking down radiosonde weather balloons.

Mark's custom KerberosSDR HUD seen on Twitter

Mark writes:

For the last few months I've been piecing together a radio direction finding (also known as 'fox-hunting') system using a RTLSDR-Blog Kerberos-SDR, a custom-made antenna array, and my 'ChaseMapper' software. I have also recently added a 'heads up display' (HUD) box which displays the direction-of-arrival and SNR data from the Kerberos-SDR software.

I hope to put together a longer video showing how the system goes together sometime in the future, but this short clip shows how the system is used in the final approach to a radio transmitter (in this case, a 144 MHz transmitter from one of the Amateur Radio Experimenters Group organised night fox-hunts).

The antenna array consists of two 4-element nested arrays, one with 200mm antenna spacing for the 70cm band, and another with 425mm antenna spacing for the 2m band. The array is mounted to my car roof-racks, with phase-matched coax entering the car through a window-mounted bulkhead.

The red lines on the map indicate a bearing line produced by the Kerberos-SDR software. As we drive around the fox location, bearings are plotted, and we look for where they cross. There are always some inaccurate bearings due to multi-path issues, and misalignment between bearing acquisition time and the position/heading of the car, but it works well enough to be able to allow navigation to the transmitter location. The display can get fairly busy, so there are options to threshold by signal quality, and to 'age out' bearings over time.

The beeping noise you hear in the video is the signal from the radio transmitter, in this case a 144.390 MHz beacon which transmits short CW 'pips'. We were listening to the signal with an Icom IC-705 attached to an omnidirectional antenna so we knew when the transmitter started and stopped (and hence when to trust any bearings produced by the DoA system).

Towards the end of the video you can see the HUD in action, with the blue lights showing the estimated signal arrival direction, relative to the front of the car. As I slowly drive past the transmitter location (which I could see out the side of the car), the bearings swing to the right, and the SNR shows as being very strong. This is exactly what the display was intended for - it's not about getting hyper-accurate bearings, but more knowing when you need to turn left/right, or get out of the car!

Thanks to Will Anthony for capturing the video while I was driving!

Software used:

AREG Fox-hunt Activities: https://www.areg.org.au/archives/category/activities/fox-hunting

Finding a Radio Fox using a Kerberos-SDR + ChaseMapper

KerberosSDR is our 4-channel phase coherent capable RTL-SDR unit that we previously crowdfunded back in 2018. With a 4-channel phase coherent RTL-SDR interesting applications like radio direction finding (RDF), passive radar and beam forming become possible. It can also be used as four separate RTL-SDRs for multichannel monitoring.

KerberosSDR is soon to be replaced with the upgraded KrakenSDR, which will begin crowd funding on Crowd Supply later this year. Be sure to sign up on the Crowd Supply page to be updated once the campaign releases as due to long supply chain crisis related lead times, only a limited amount of stock will be initially available.

Andreas Spiess Tracks Weather Balloons with a TTGO LoRa Board and RTL-SDR

Earlier in August we posted about radiosondy.info and the MySondy radiosonde receiver. Radiosondy.info is an internet service that aggregates radiosonde weather balloon data received and decoded by RTL-SDR users all over the world. MySondy is a cheap TTGO LoRa receiver that is modified with custom firmware and combined with a companion Android app in order to create a portable radiosonde receiver. A radiosonde is a small sensor and radio package normally attached to a weather balloon. Meteorological agencies around the world typically launch two balloons a day from several locations to gather data for weather prediction. With cheap hardware like an RTL-SDR and the right decoding software it is possible to receive weather and GPS data from the weather balloons launched in your area. 

Over on his popular YouTube channel, Andreas Spiess "the guy with the Swiss accent" has uploaded a video featuring the RadioSondy and the MySondy receiver projects. In the video Andreas first explains what a radiosonde is, and who launches them. He goes on to show the RadioSondy website and how to track balloons on it. He then shows the portable MySondy receiver for tracking radiosondes, before finally showing how to set up a permanent fixed ground station with RTL-SDR and Raspberry Pi for contributing to the RadioSondy aggregation website.

In amongst the demonstrations he also goes on several hunts for weather balloons that have landed near him, ultimately recovering two radiosondes and one intact balloon. The radiosondes were initially tracked with the RadioSondy fixed RTL-SDR ground stations, then when in the vicinity of the landed balloon pinpointed and found with the MySondy hardware.

#360 Tracking and Chasing Weather Balloons with TTGO LoRa board and Raspberry Pi. Fun and adventure

MySondy: Radiosonde Tracking Firmware for a TTGO ESP32 LORA Board

A radiosonde is a small sensor and radio package normally attached to a weather balloon. Meteorological agencies around the world typically launch two balloons a day from several locations to gather data for weather prediction. We have featured radiosondes several times on this blog as it is easy to use an RTL-SDR and computer to receive and decode their signals, which can used to hunt down the fallen sonde, or to receive the weather telemetry data.

Recently RTL-SDR.COM reader António submitted a link to an interesting project called "MySondy" which is created by Mirko Dalmonte (IZ4PNN). MySondy is custom firmware for TTGO Lora32 433 MHz boards which allows them to be turned into a radiosonde tracker. A TTGO is a cheap ~US$20 LoRa32 IoT dev board with an onboard WiFi + Bluetooth enabled ESP32 microcontroller and OLED display. Some of the slightly higher priced units come with a built in GPS receiver as well. With the custom firmware it is capable of receiving and decoding common radiosonde protocols such as RS41, M10, RS92 and DFM.

A TTGO ESP32 LoRa Board
A TTGO running MySondy firmware enclosed in a 3D Printed Case

There is also an Android App called MySondy Go and MySondy FINDER which connect to the TTGO via Bluetooth. This app plots the location of the radiosonde on a map, allowing you to easily follow and track down the balloon. You can also go to mysondy.altervista.org to see public MySondy stations. Clicking on a blinking dot will connect you with the MySondy server, allowing you to see tracked sondes.

MySondy Web Interface

The firmware and software appear to be fairly new, so there isn't much information about this that we could find just yet. Also we note that all manuals and information about the project is written in Italian, except for a French magazine article (pdf) that António sent us to upload.

We note that these TTGO ESP32 LoRa boards are quite interesting by themselves, with other custom firmware available to do things like create a Paxcounter which counts the number of mobile devices in an area via WiFi and Bluetooth signals, and the ability to use them as a GPS enabled Mesh network based text message radio.

Tracking and Recovering A NWS Weather Balloon & Radiosonde with an RTL-SDR

Over on YouTube OLHZN High Altitude Balloons has posted a very entertaining video showing how to use an RTL-SDR and small grid dish antenna to track and recover a fallen weather balloon and its radiosonde. OLHZN writes:

The US National Weather Service (#NWS) launches over 200 weather balloons everyday carrying an LMS-6 #radiosonde / rawinsonde made by Lockheed Martin to an altitude of over 100,000 ft. and you can track & follow the flights from home and even find the landing site and pick them up! This is a fun #DIY project that you can do yourself from home and I'll show you how to do it here along with some tips so you can go find yourself a weather balloon & radiosonde!

How to track & recover a NWS weather balloon & radiosonde 🎈🎈 Ham Radio DIY

Tracking Radiosondes with an RTL-SDR and Radiosonde_Auto_RX

A radiosonde is a small sensor and radio package normally attached to a weather balloon. Meteorological agencies around the world typically launch two balloons a day from several locations to gather data for weather prediction. With an RTL-SDR, appropriate antenna and decoding software it is possible to decode the telemetry signal and gather the weather data yourself. You can also use the GPS data to chase and collect the fallen radiosonde package. We have a tutorial on setting up a basic radiosonde decoder in Windows here.

However, if you want to set up a permanent radiosonde receive station it's possible to create an automatic system with a program called radiosonde_auto_rx. It works by performing an rtl_power scan over the radiosonde frequency range and looking for peaks that might indicate that a radiosonde is currently transmitting. If a peak is found it tries to decode it as a radiosonde, and if successful will begin uploading the weather data to an online aggregation site called sondehub.org. With this sort of system there is no need to know in advance the launch times and exact frequencies that your local meteorological agency uses, as often this information is not public.

Recently Mark Jessop and Michael Wheeler, the team behind radiosonde_auto_rx, also did a talk at the linux.conf.au conference. The talk explains radiosondes and demonstrates their software in action. They then go on to talk about chasing radiosondes, and re-purposing collected sondes.

[Also seen on Hackaday]

STM32 Development Boards (literally) Falling From The Sky

Aggregating Weather Balloon Data Online with a Custom Raspberry Pi Image

Thanks to a RTL-SDR.COM reader for submitting a tip about radiosondy.info, a weather balloon data aggregation website made by SQ6KXY. Weather balloons carry a sensor and transmitter payload called a radiosonde. These radiosondes transmit their data to a ground station via an RF signal, which is typically at around 400 - 406 MHz in most countries. With an RTL-SDR and decoder software (related tutorial) it is possible to receive and decode their weather data, and also often their GPS location data. The location data can be used to find and collect radiosondes once they reach the ground.

SQ6KXY has created a website called radiosondy.info which aims to aggregate and make weather balloon data received by contributors public. It is similar to sites like flightradar24 which aggregate ADS-B data from aircraft. The main page allows you to view radiosondes that are currently flying, and the archive of previous flights.

To make contributing to the site as simple as possible, SQ6KXY has created a custom image for the Raspberry Pi, which is automatically generated by the website for your particular user account, local radiosonde frequency requirements, and number of SDRs. They don't specifically mention it, but we assume that contributors are mostly using RTL-SDRs in their receivers. The custom image is available for generation after signing up.

Web tool to generate a custom Raspberry Pi Image for Radiosonde Tracking
Web tool to generate a custom Raspberry Pi Image for Radiosonde Tracking

Tutorial on using RS to Decode and Plot Radiosondes

A radiosonde is a small weather sensor package that is typically attached to a weather balloon. As it rises into the atmosphere it measures parameters such as temperature, humidity, pressure, GPS location etc, and transmits this data back down to a receiver base station using a radio signal.

Zilog's RS is a free open source radiosonde decoder for Linux and it supports a wide range of radiosonde protocols. Together with an RTL-SDR it is possible to receive radiosonde signals, and decode them using RS.

Over on his website, happysat has recently uploaded a tutorial that shows how to use RS with an RTL-SDR, CubicSDR or GQRX, and FoxtrotGPS, a GPS plotting program for visualizing the location of the radiosonde. The tutorial covers some tricky points like setting up audio piping in Linux, and getting the GPS data into a virtual COM port to use with FoxtrotGPS.

Alternatively, there are also Windows GUI based sonde decoders that can be used with the RTL-SDR such as SondeMonitor which costs 25 Euros, but also covers a wide range of sonde protocols, and RS41 Decoder which is a GUI for the RS41 sonde protocol only. If you are interested we have a tutorial on setting up radiosonde decoding in Windows with SondeMonitor available here.

Plotting the Sonde Location with an RTL-SDR, GQRX, RS and FoxtrotGPS.
Plotting the Sonde Location with an RTL-SDR, GQRX, RS and FoxtrotGPS.

RS41 RadioSonde Tracking Software

A radiosonde is a small weather sensor package that is typically attached to a weather balloon. As it rises into the atmosphere it measures parameters such as temperature, humidity, pressure, GPS location etc, and transmits this data back down to a receiver base station using a radio signal. The RS41 is one of the newer radiosonde modules sold by  radiosonde manufacturer Vaisala, and is currently one of the most popular radiosondes in use by meteorological agencies. The signal is typically found at around 400 MHz and can be received with an RTL-SDR and an antenna tuned for 400 MHz. We have a general tutorial on radiosonde decoding available here.

There are several software packages that can decode RS41 data, such as the multi-radiosonde decoder Windows program called SondeMonitor (25 euros), or the free Linux command line software called RS. Recently a new free Windows GUI based RS41 decoder has been released by IW1GIS. The software can display on Google maps the current location and previous path of the radiosonde, as well as it's weather data telemetry.

Main features are:

  • Directly decoding of GFSK signal received by the FM radio receiver (the use of a Software Defined Radio is recommended).
  • Capability to connect and command SDRSharp software by mean of Net Remote Control plugin.
  • Advanced frequencies scan and decode: RS41 Tracker is able to look for RS41 radiosonde signal in a given list of frequencies, starting the radiosonde decoding when a valid signal is detected.
  • Real time showing radiosonde position on google map (internet connection is required)
  • Map auto centered on radiosonde position
  • Map type selectable by user (road, satellite, hybrid, terrain).
  • Burst killer detailed information and launch time estimation.
  • Radiosonde RAW data save
  • Post processing of RS41 RAW data file
  • Tracking information (elevation, bearing, slant range)
  • Radiosonde track saved on kml file
  • Ghost track shown on map (loading from kml file)
  • Shortcut for google maps in browser
RS41 Tracker Software
RS41 Tracker Software