Few radio amateurs use the telemetry functionality of APRS. We count telemetry as any standard or BASE91 telemetry packet. Over a 24 hour period we’ve observed around 44 distinct stations with an average of 13 stations sending telemetry over 5 minute periods. This pales in comparison to the entire APRS-IS stream which in 24 hours averages 7,000 distinct stations and totaling over 31,000 stations sending a packet. This means just 0.13% of the APRS user base sends a telemetry packet. Disappointing.
Amateur radio was founded in experimentation and remote telemetry is paramount to exciting experimentation. FaradayRF is changing this. The Faraday radio is designed with remote sensing as a core design principle and presents operators with direct access to ADC and SPI sensors. Our software formats and sends out high resolution BASE91 APRS telemetry too. There is just one missing piece… Viewing APRS telemetry.
We’ve been hard at work integrating open source technology with the APRS-IS system to make ham radio telemetry useful. In the process, we wrote aprs2influxdb as part of our #LaunchWithFaraday buoy project. Our new service is located at https://telemetry.faradayrf.com and centers around providing immediate and aesthetically pleasing access to APRS data. This service is not limited to FaradayRF owners and is free for use by all APRS stations regardless of hardware used. We invite you to view and share this website with others but please keep the following in mind:
- Telemetry.FaradayRF.com is a beta service so reliability is not guaranteed at this time.
- All APRS data older than 24 hours is deleted from the database
Data is Beautiful
How many of us have launch a High Altitude Balloon and used aprs.fi to track it? Most, I would assume. It’s simple, just works, and is already available. We have to write custom programs to plot our APRS data or export it from aprs.fi using CSV files. This is messy. With the FaradayRF Telemetry service you can track your High Altitude Balloon Telemetry in real-time. We watched AE0SS-12 fly just outside of Denver, CO on Sunday October 22, 2017 using Telemetry.FaradayRF.com. This balloon peaked around 29,441 meters (about 96,000 feet) before descending to the ground. It also reached a peak speed of 161 km/h during flight when the payload traveled through the atmosphere at 10km altitude! Check out AE0SS-12 on telemetry.faradayrf.com yourself!
So don’t spend time worrying about designing a telemetry dashboard service for your project. Use Telemetry.FaradayRF.com dashboards as your user interface and focus on building what matters… a successful mission.
Faraday Radios Are Designed for Telemetry
While Telemetry.FaradayRF.com supports all APRS stations, just 0.13% of all APRS stations actually sent out standard or BASE91 telemetry packets. Out of the box our radio sends five analog measurements into all five available APRS telemetry fields at 12 bit accuracy. It can send more measurements… but we’re limited by APRS-IS at this time. Every one of you who owns a Faraday radio is helping increase traffic of this underutilized APRS feature and therefore helping push ham radio into the future. You rock!
Above is a test using a Faraday radio over RF. You can play with the data here! This is the initial view of our current dashboard showing all relevant information. We have immediate indication of current speed and altitude along with a graph over time of both. Since this station was stationary, you can see GPS altitude wander as the satellites move overhead. All four analog measurements which are not board temperature values are shown as gauges. Since we do not currently scale telemetry yet, you are seeing raw ADC bits with a maximum value of 4095.
Scrolling down more we see the image shown above which plots all four ADC values on the same graph with Analog 4 using the right axis. Analog 4 is the battery voltage which clearly shows a discharging battery over the duration of the test! Below that we see the board temperature plotted as the mean value of all data in 5 minute intervals. There were some drops in data here which is unusual but the dashboard is set to null these out so it is obvious there is missing data. Lastly, the list at the bottom shows all Faraday radios heard on APRS-IS within the time period being viewed.
Grafana is an open source tool largely used to view data center health such as CPU use, disk space, user count, etc. We’ve leveraged Grafana to help radio amateurs. Here are some tips to navigate around:
The top left of the Telemetry website has and area you can click and see all available dashboards as well as search using name/keyword filters.
Sharing Station Dashboards
Also near the top left is a sharing icon (arrow) which shows several options related to sharing the current dashboard. Linking to the dashboard simply sends someone to the current view/time range of the station currently being observed. Creating a snapshot will save the data to the web server (it will not delete in 24 hours per database rules) and allows anyone to view the data as if it were in the database. I shared a snapshot of AE0SS-12 earlier in this blog post! Please avoid setting expiration to “Never” when possible. We may prune snapshots as needed.
On certain dashboards there is a “Callsign” variable which can be changed. Clicking on the callsign drop-down menu shows several pre-selected options. However, you may type in all caps any callsign-id (i.e. KB1LQC-1) to search our database.
Changing the Time Range
The top-right of most dashboards has an area you can see the current time range being shown. Often this is “Last Hour” with a refresh rate of once per minute or similar. Clicking on this allows you to enter custom time ranges as well as several suggested ranges and refresh rates. Remember, we drop all data older than 24 hours from our database at this time.
Exporting CSV Data
Grafana tables and graph titles open a menu when clicked on. Clicking on the “hamburger” icon in this menu opens up an option to export data as a CSV file.
We Hope You Enjoy Telemetry
Let us know what you think of our project! We aim to benefit all radio amateurs using APRS with this service and while we hope you will purchase a Faraday Radio to experiment with we also encourage you to use any APRS hardware or software. Amateur radio is becoming more exciting by the day as we leverage open source technology to breath fresh air into amateur radio. Subscribe below to stay up to date with our projects and leave a comment about this blog post below!
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Author: Bryce Salmi
Licensed radio amateur KB1LQC and Co-Founder of FaradayRF. Professional Electrical Engineer designing and building avionics for rockets and spacecraft during the day and developing the future of digital amateur radio experimentation by night. All opinions are my own.