The Bunker has long since had AX.25 packet radio and APRS functionality, but in the summer of 2024 we added a UHF LoRa APRS iGate. Both iGates are receive only.
AX.25 APRS (144.800 MHz)
The AX.25 settings are in line with long-established APRS procedures in the EU.
| Parameter | Value |
| Callsign | GB0SNB-1 |
| Radio | RTLSDR V3 & custom RF front end – see our SDRs page |
| Frequency | 145.8000 MHz |
| Signal Bandwidth | 2.5 kHz (in 12.5 kHz channel) |
| TX Power | Receive only |
| Antenna | Diamond V-2000 at 38m AGL |
| Software | DireWolf (via OpenWebRX+) – see our SDRs page |
LoRa APRS (439.9125 MHz) : GB0SNB-2
The LoRa settings here were chosen to match those used the SOTA Group. Note that the UK frequency is different to the default EU frequency.
| Parameter | Value |
| Callsign | GB0SNB-2 |
| Module | LilyGo TTGO LoRa32 V2.1_1.6 |
| Radio | Samtech SX1276 |
| Frequency | 439.9125 MHz |
| Spreading Factor | 12 |
| Signal Bandwidth | 125 kHz |
| Coding Rate 4 | 5 |
| TX Power | Receive only |
| Antenna | 4-stack colinear array at 46m AGL |
| Software | LoRa APRS iGate, ver 2024.08.14 |