What product do you wish to discuss? RAK10724 WisMesh 1W Booster Starter Kit (RAK3401 + RAK13302 + RAK19007)
Computer OS? Windows (using Meshtastic app for configuration)
How often does the problem happen? Consistently, across all three kits
How can we replicate the problem? Assemble the RAK10724 kit per the quick start guide, flash the rak3401-1watt firmware, set TX power to 30 dBm, and compare RSSI at short range against a T-Beam.
Background
I purchased three RAK10724 WisMesh 1W Booster Starter Kits for use as Meshtastic ROUTER nodes. All three exhibit the same behavior: the SKY66122 PA does not appear to be engaging. Transmit performance is significantly worse than LILYGO T-Beams running at stock power (~160mW / 22 dBm).
Hardware Configuration
- Core: RAK3401 (nRF52840)
- LoRa module: RAK13302 1W (SX1262 + SKY66122)
- Base board: RAK19007 (2nd gen)
- Firmware: rak3401-1watt, version 2.7.26 (flashed via https://flasher.meshtastic.org, selected “RAK3401 1W”)
- Firmware self-identifies as the 1W variant in the Meshtastic app
- TX power: Set to 30 dBm in Radio Configuration → LoRa
- Region: US (915 MHz)
- Antenna: Connected to the RAK13302 IPEX port (NOT the RAK19007 base board IPEX port — visually confirmed)
- LiPo: 3.7V 2000mAh connected to RAK19007 JST PH 2.0mm battery port
- External power: Voltaic V75 battery bank via USB-C to RAK19007
Jumper Positions Tested
Both jumper positions on the RAK13302 3-pin header have been tested:
- IN_5V (bridging IN_5V to center): LiPo connected, USB power via base board USB-C. Same weak result.
- EX_5V (bridging EX_5V to center): USB power via base board USB-C. Same weak result.
Neither jumper position changes the transmit behavior.
The Problem — Comparative RSSI Data
All devices tested in the same room, approximately 5 feet apart, same antenna position, same receiving device (T-Beam “Alpha” paired to phone via Meshtastic app):
| Device | Hardware | TX Power (configured) | RSSI | SNR |
|---|---|---|---|---|
| Gamma | LILYGO T-Beam (stock) | ~22 dBm (160mW) | -45 dBm | Strong |
| Delta | LILYGO T-Beam (stock) | ~22 dBm (160mW) | -30 dBm | Strong |
| Zeta | RAK10724 (RAK3401 + RAK13302) | 30 dBm (1W) | -79 dBm | 10 dB |
The RAK13302 at “1W” is 34-49 dB weaker than T-Beams at 160mW in the same location.
If the PA were simply not amplifying (passthrough), I would expect roughly equivalent performance to the T-Beams (~22 dBm from the bare SX1262). The fact that the RAK13302 is dramatically worse suggests the unpowered PA circuit is acting as an attenuator — the signal passes through the inactive SKY66122 and loses significant power in the process.
What I Have Tried
- Flashed firmware via web flasher — confirmed rak3401-1watt variant
- Verified antenna is on the RAK13302 IPEX port, not the base board
- Tested both IN_5V and EX_5V jumper positions
- Tested with and without LiPo battery
- Tested with USB power connected before and after LiPo (different boot-up detection: “PWR” vs “BATT” modes)
- Confirmed TX power reads 30 dBm in the Meshtastic app
- Tested across three separate RAK10724 kits — all three show the same behavior
Observations
- RX performance is improved over the T-Beams. The SAW filter and LNA on the receive path appear to be working — the RAK nodes hear distant nodes that the T-Beams cannot. This suggests the receive-side components are powered and functional; only the TX PA is not engaging.
- The Meshtastic app shows different power source detection depending on boot order: USB first shows “PWR 4.19V”, LiPo first shows “BATT 98% 4.16V”. Neither mode produces correct TX output.
- All three kits exhibit identical behavior, ruling out a single defective unit.
Related Threads
- RAK6421 + RAK13302 not outputting 1W — Same PA not engaging, different platform (RAK6421 Pi HAT). A reply suggests the ANT_SW / PA_CSD pin may need to be held high.
- RAK8623: RAK13302 PA not engaging at full 1W on meshtasticd 2.7.15 — Same symptom on WisMesh Station HP, unresolved as of July 10, 2026.
Those threads are on the Raspberry Pi / meshtasticd platform. This report confirms the same PA issue exists on the WisBlock (RAK3401 + RAK19007) platform with the native UF2 firmware.
Questions
- Is there a known-good firmware version where the PA is confirmed working on the RAK3401 + RAK13302 + RAK19007 combo?
- Does the rak3401-1watt firmware variant correctly assert the PA enable pin (ANT_SW / PA_CSD on the SKY66122) during transmit?
- Is there a hardware configuration step or additional jumper/connection that is not documented in the quick start guide?
- What RSSI values should I expect at short range (5 feet) if the PA is functioning correctly at 1W?
Thank you.