Announcing kiss-tnc-bridge

I just created and released a new piece of open source software called kiss-tnc-bridge. This daemon bridges Bluetooth KISS TNC clients to TCP KISS TNC servers. Here’s why I created it, how it works, and how you can use it.

Why does this exist?

If you already have a KISS TNC server running on TCP, why would you want it to work via Bluetooth?

1. In a scenario where power consumption matters more than range, Bluetooth Low Energy uses less power than WiFi.
2. On Apple’s iOS, the aprs.fi app cannot use WiFi when it’s not the foreground app. But it can use Bluetooth, allowing it to remain connected in the background.
3. I created a portable APRS station using Graywolf on a Raspberry Pi. Graywolf can be configured to create a TCP KISS TNC so multiple apps can use the radio set up in Graywolf. kiss-tnc-bridge lets a mobile device use Graywolf’s TNC without having to have any WiFi available.

How I use it

I have built a setup I call an APRS Command Center. I’ll do a more detailed write up soon. To summarize, I want an APRS station that supports some or all of these functions, depending on the scenario:

• portable (i.e. work in a car, easy to set up in a remote location)
• flexible radio/antenna options (digirig connected to a 50 W mobile radio and an X300 on a 25 foot mast, or my TH-D75 connected via USB cable)
• multiple options for power (solar, USB-C battery, 12V power, 13.8V power)
• doesn’t require internet access
• can be an igate if internet access is available
• shows a live map of APRS stations, which needs to work with no internet access
• can beacon my location, as well as objects and locations of other assets

I want a station I can use at a race event where there is no internet access.

This station will be most useful when co-located with net control. In that setting, it is likely that other devices, like a phone running aprs.fi, may want to connect to the station to send/receive their own APRS packets using the radio connected to the APRS Command Center. Graywolf can easily offer a TCP KISS TNC. This new kiss-tnc-bridge also offers another method to connect, and has the important benefit that it doesn’t require WiFi to work.

Feedback welcome

If this software is useful to you, I’d love your feedback. Open an issue on GitHub or contact me directly.