What I Was Looking For

Each firmware I tested had its own pros and cons. However, my main focus was very specific:

• ✅ Proper TNC functionality
• ✅ BLE TNC support (for mobile apps like APRSdroid)
• ✅ Reliable APRS text messaging
• ✅ Simple configuration and stability

For me, LoRa APRS isn’t just about position beacons — I want proper interactive APRS capability.

Hardware Used

iGate

• Heltec Wireless Stick Lite V3 (433 MHz)
  Used as a LoRa APRS iGate.

Tracker

• Heltec HTIT Tracker (433 MHz)
  Used as the portable tracker node.

Testing CA2RUX Firmware

Let’s start with the CA2RUX LoRa APRS Firmware.

Installation Experience

The firmware was very easy to install using the web-based flashing tool provided via GitHub Pages. No need to manually build binaries — just connect the device, select the correct board, and flash.

Installation worked smoothly for both:

• iGate (Heltec Wireless Stick Lite V3)

• Tracker (Heltec HTIT)

This is a big plus, especially for newcomers to LoRa APRS.

iGate Setup

The iGate configuration was straightforward:

• Device boots into Wi-Fi AP mode

• Connect via browser

• Enter callsign, select APRS overlay & symbol, APRS-IS details, LoRa parameters and telemetry settings 

• Save and reboot

Very clean and simple workflow.

Important Frequency Entry Issue

One issue worth highlighting:

When entering the LoRa TX/RX frequency, the field do not have a decimal point.

For the UK LoRa APRS frequency:

439.9125Mhz

You must enter it as:

439912500

I mistakenly entered it with a decimal point initially, which caused IGate to be stuck in boot loop. Had to reinstall firmware.

Tracker Setup

Installation on the tracker was identical to the iGate process — flash via the web tool, connect to the temporary Wi-Fi access point, and configure callsign, frequency, and APRS parameters.

However, the behaviour after setup is slightly different compared to the iGate.

Default Behaviour After Configuration

Once configuration is completed via Wi-Fi AP, the tracker reboots into:

• Bluetooth TNC mode only

This means:

• Wi-Fi AP is disabled by default
• You cannot immediately re-access the configuration page

To make configuration changes later, you must:

1. Use the device menu
2. Manually re-enable Wi-Fi AP
3. Reconnect via browser
4. Modify settings

While this isn’t a major issue, it does make quick adjustments slightly inconvenient — especially during field testing.

BLE TNC Testing

One of my main goals was testing BLE TNC support for use with APRSdroid.

Unfortunately, BLE TNC did not work reliably.

The issue is not entirely firmware-related — APRSdroid does not properly support BLE TNC. It works far more reliably with:

• AFSK (Audio)
• Classic Bluetooth SPP
• Or Serial (USB) TNC

So even though BLE is supported by the firmware, in practice it’s not very usable with APRSdroid at the moment.

For anyone specifically wanting Android APRS messaging, this is an important limitation.

Serial TNC Testing

Another key test for me was:

Can I use it as a proper Serial TNC with PC APRS applications?

I attempted to connect the tracker firmware via USB Serial TNC to various PC applications, but I was not able to establish a working connection.

No reliable KISS TNC functionality over serial was achieved during testing.

For my use case — where proper TNC functionality is a priority — this was a significant limitation.

Summary So Far – CA2RUX Tracker

👍 Pros

• Easy installation via web flasher
• Clean Wi-Fi configuration interface
• BLE TNC for KISS and TNC2 mode available
• Good beginner-friendly setup

👎 Cons

• Wi-Fi AP disabled after setup (must manually re-enable)
• BLE TNC not practical with APRSdroid
• Serial TNC not working in my testing
• Frequency entry UI can cause mistakes

Testing SQ2CPA Firmware

While exploring forms for Serial TNC I came across the SQ2CPA LoRa APRS Firmware — and it immediately stood out.

Unlike many other LoRa APRS firmware projects, this one offers:

• ✅  Android application (APK download)
• ✅ Web-based configuration
• ✅ Wi-Fi AP and Wi-Fi Client modes
• ✅ Serial TNC
• ✅ Bluetooth connectivity
• ✅ TCP/IP access for iGate

This made it feel like a more complete ecosystem rather than just firmware.

Installation & Setup

Installation was straightforward using the web flasher — similar simplicity to CA2RUX.

Initial configuration is done via:

1. Boot into Wi-Fi AP mode
2. Connect via browser
3. Enter callsign, LoRa frequency, APRS-IS details for IGate, etc.

After setup, the device can:

• Operate as a Wi-Fi client (connect to your network)
• Be accessed over your local Wi-Fi network

This makes remote management much easier compared to CA2RUX firmware.

Android App Integration

One of the most interesting features is its own dedicated Android application (APK install only).

You can:

• Connect to the tracker via Bluetooth
• Connect to the iGate via TCP/IP
• Send APRS messages
• Monitor packets

This provides a much more integrated user experience compared to relying on third-party apps like APRSdroid.

For users who want a plug-and-play experience, this is a major advantage.

APRS Symbol & Layout Configuration

One issue I encountered was with:

• APRS symbol selection
• Layout/icon configuration

Getting the correct APRS icon required some trial and error. The configuration options are powerful, but not immediately intuitive.

If you’re particular about how your station appears on APRS maps, expect to spend some time adjusting symbol table and symbol codes.

Once configured correctly, it works fine — but the setup process could be clearer.

Important Behaviour – GPS Lock Required

One very important note:

Trackers running both CA2RUX and SQ2CPA firmware will not transmit messages until they have a valid GPS fix.

This applies to:

• Position beacons
• APRS messages

If you power up indoors without GPS lock, the tracker will appear silent.

For field use, this is logical.
For bench testing, it can initially be confusing.

Overall Impression So Far

Compared to CA2RUX:

• SQ2CPA feels more complete
• Serial/TNC functionality is more central to its design
• The Android app improves usability
• Wi-Fi client mode is a strong advantage
• Symbol configuration needs refinement

73’s

2E0UMR

Transparency Note:

I used AI tools to help refine grammar and structure in this article.
All technical testing, conclusions, and practical findings are entirely based on my own hands-on work.