I surprised myself with a Lilygo T-TWR Plus ESP32-S3 after seeing this video about a APRS software for this board: https://www.youtube.com/watch?v=wJTNMjpJB98
The board can be obtained from different suppliers (note that there are different versions for VHF and UHF – and do not order the “open version” !) for around $70.
The software is available here, including instructions about flashing it to the board: https://github.com/nakhonthai/ESP32APRS_T-TWR
Here are my first impressions:
– the board comes with a HT-software pre-programmed on it. This is nice for testing, but there are better FM HTs around, so you will really want to flash the APRS-software to it. Flashing it is easy, if you follow the instructions
– the board uses a 27100 lithium cell, which I still have to order, but there is a small spring included in the package and by printing this adapter (https://www.thingiverse.com/thing:2837524) and adding the spring to it, I could insert a standard 18650 cell (note the polarity printed on the board!)
– I also printed a case, but it is hard to remove once the boards “snaps” into the case. I will probably modify the case a little bit, otherwise it will be hard to remove/replace the battery
– I still don’t know, if the board charges the battery when connected to a 5V USB-connector
– connecting the wifi AP of the board does not work for almost all of my devices, we had no luck with Samsung, Apple and Microsoft devices, only a Xiaomi phone could connect to it
– the board connects to a wifi, but the password string must not be longer than 12 characters (I created a guest-wifi for that reason)
– the board receives and displays APRS-beacons of my FT-3D, it also reports them to the Internet (I-gate mode)
– the board transmits beacons, but my FT-3D decodes only approx. every 5th beacon
I still have to figure out, why the transmitted beacons are not always being decoded. Two digitpeaters/I-gates around Kiel decoded some (?) beacons. Increasing the preamble did not help. I can set two different bandwidths and there are also filter settings (for transmit or for receive or both ?) to play with. For now I can say, that the board works great as an I-gate. I will have to do more tests with the digipeater and tracker modes and report about these tests later…