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AIDA3 PCUSB Serial CablePersonal PC (Windows)
What frequency are these set to? Why?Why do the antennas need to be connected before powering?What is special about the USB Serial plug?What is pin one on the RFD900 USB Serial Connector, and what color wire connects to it? Please attach a photo before plugging it into your computer's USBWhat is BAUD?
Download and install RFDTools on one computer.Connect both RFD900 unitsThe ground unit connects to the RFDTools PC.The air unit connects to another PC.Fill out the Purpose Column to explain what the setting changes (review the manual).Print a label for both the ground and air unit with your group name (AIR-1; GROUND-1)
Open PuTTY.Connect one modem per computer.Open Device Manager from the start menu.OR: Hold the Windows Key + R > type devmgmt.msc > hit enterExpand the Ports (COM & LPT) headingLook for “USB Serial Port (COM3 / 16)” and record this number
In PuTTY enter the following:COM# > Serial lineSpeed > 115200Hit Open
You should now be able to type between computers and visualize the display. Send a “hello world" message between the computers and attach a screenshot.
The file provided by Windracers has a .apj file extension. What does this mean and why?What is Mission Planner? What are the alternatives to Mission Planner? Mission Planner is a free ground control software that we will be Do you expect the Windracers flight controller firmware to work with Mission Planner?How much memory does the Blue Cube have? 2MB
If not already installed, download and install Mission PlannerYou will need an admin account - ask your instructorAttach a screenshot of the completed firmware installation.
On an AIDA3 PC, open Ground Control.Be sure that the flight controller is connected via USB.Navigate to Settings and click on Connection
Create a new connection with the following settingsType: SerialBaud Rate: 115200
The aircraft should automatically connect and be visible in the Flight Plan menu. Attach a screenshot.
Lab 08 - Believer Comms and Firmware
Overview
Resources
Hardware and Software
Readings
Activity 1: Set up RFD900x
Specification Questions
Answer the following questions about the specifications on the telemetry module.
902-915MHz and 915-928MHz. For interference mitigation.
Without the antennas connected, the power would have nowhere to go would fry the telemetry receiver.
It has a 6 pin connector on one end.
Pin one is the farthest left most pin on the connector, black.
How fast data is transferred per second
Settings
Adjust the modem’s settings for your group.
RFD900 Settings
Group Number
Setting Name
Default
Set Value
Purpose
5
2
SERIAL_SPEED
57
115
Open
NETID
25
125
Open
Testing Communication
Send hello world! to your neighbor. With your ground and air unit set correctly, you can now communicate point-to-point between both modems. You will need two computers - follow the steps below for both.
Activity 2: Installing Firmware
Specification Questions
Its a specific file type that is used to load firmware onto flight controllers.
Yes.
Installing Firmware
You will be provided with the precompiled firmware on a flash drive. All work on the flight controller must be completed on an AIDA3 PC.
Testing
Now we will test the connection with the Windracers Ground Control app.
Individual Reflection
Overview of Lab
In this lab, our group configured the Believer’s communication link and installed the correct firmware on the Cube so that it could operate with the Windracers ground control software. We first set up the RFD900x telemetry radios to establish a reliable serial link between two computers, similar to the link that will be used between the aircraft and the ground control station. Then we flashed the Cube with the provided .apj firmware file using Mission Planner and verified that Windracers Ground Control could connect to the Cube and display the aircraft status. I was a member of Group 5 and participated in both the telemetry setup and the firmware installation, working together with my teammates to make sure each step was completed correctly and safely.
Procedures Completed
1. RFD900x Setup and Communication Test
As a group, we began with the telemetry radios. We connected one RFD900x (ground modem) to the AIDA3 PC and the other (air modem) to a second computer using USB serial adapters. We used Device Manager to confirm which COM port each radio was using.
Next, we opened the RFD tools and read the existing parameters from each modem. For our group, we changed the SERIAL_SPEED to the required value (115200) and set a unique NETID for Group 5 so that our radios would not interfere with other groups. After writing the new settings to each modem, we power-cycled them to make sure the changes took effect.
To test communication, we used PuTTY on both computers. On each side, we selected the correct COM port, set the baud rate to 115200, and opened a serial session. When we typed text on one computer, it appeared on the PuTTY window on the other computer, and vice versa. This confirmed that our RFD900x radios were correctly configured and that the link was bidirectional and stable.
2. Cube Firmware Installation and Ground Control Test
After confirming the telemetry link, we moved on to the Cube firmware. We connected the Cube to the AIDA3 PC via USB and opened Mission Planner. Following the lab instructions, we selected the option to load custom firmware and chose the provided .apj file for the Believer/Windracers configuration. We then allowed Mission Planner to upload the firmware to the Cube, waited for the progress bar to complete, and let the Cube reboot.
Once the firmware was installed, we verified that Mission Planner could connect to the Cube over the correct COM port and baud rate. Then we opened Windracers Ground Control, set the connection type to Serial, chose the same COM port, and used the proper baud rate. When we connected, the software recognized the Cube and showed the aircraft in the interface, confirming that the firmware and communication settings were correct. I helped with identifying the COM ports, confirming the baud rate, and checking that the ground control display matched what we expected from the lab handout.
Connection to Lab Questions and Objectives
The procedures we followed directly connected to the questions and learning objectives in the lab. For the RFD900x section, the specification questions about frequencies, antennas, and baud rate became much clearer after configuration and testing. For example, the question about why the antenna must be attached before powering the radio made sense once we saw that the radio transmits real RF energy and could be damaged if there is nowhere for that energy to go. The questions about baud rate also connected to our PuTTY tests: if the baud rates did not match, the text link would fail or display unreadable characters.
Similarly, the firmware questions about .apj files, Mission Planner as a ground control station, and compatibility with Windracers Ground Control were directly tied to our actions. We were not just reading definitions; we actually used a .apj file to flash the Cube, used Mission Planner to perform the update, and then confirmed that Windracers Ground Control could communicate with the Cube. This helped me understand why the lab emphasizes using the correct firmware file and why a consistent toolchain is critical in real UAS operations.
Reflection on the Lab
Before this lab, I had a basic theoretical idea of what telemetry radios and firmware do, but I had never set up the full chain myself. Working with the RFD900x radios showed me how many small details—like COM ports, baud rates, NETID, and antenna connections—must all be correct for the system to function. When our radios did not communicate at first, we had to troubleshoot step by step: checking the COM ports, confirming that both sides were using the same baud rate, and verifying that the NETID matched. This experience taught me to approach communication problems systematically instead of guessing.
The firmware installation on the Cube also felt a bit risky at first, because there is always a concern about “bricking” the device. However, carefully following the documented procedure in Mission Planner and then seeing the Cube recognized by Windracers Ground Control gave me more confidence in handling firmware updates. It also reinforced how important it is to use the correct firmware version and to verify the connection afterward rather than assuming the upload succeeded.
Overall, this lab helped me see that reliable communication and correct firmware are not optional extras—they are fundamental to safe UAS operations. A misconfigured radio or incorrect firmware can result in loss of link or unpredictable behavior, which is unacceptable in real missions. Going forward, I want to keep applying the habits I practiced in this lab: double-checking parameters, verifying communication both ways, and always confirming that the firmware and ground control software are working together as intended.
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