XIAO W5500 Ethernet Adapter V1.2: Bluetooth reception 30–40 dB weaker than phone and USB dongle

Products & Technology XIAO
1

Hi,

I’m using a recently bought XIAO W5500 Ethernet Adapter V1.2 as an ESPHome Bluetooth proxy for five RuuviTag sensors. It receives every tag 30–40 dB weaker than my phone and a USB Bluetooth dongle in the same position, and the most distant tag isn’t received at all. I believe the unit is defective.

Setup

  • XIAO W5500 Ethernet Adapter V1.2 (ESPHome Ready-Made Project), ordered October 25, 2026
  • Official ESPHome Bluetooth proxy firmware (esphome/bluetooth-proxies, Seeed config); all software and firmware up to date
  • Ethernet with PoE (802.3af); passive BLE scanning of RuuviTag advertisements

Tests

  1. Antenna: checked the U.FL connection on the XIAO and replaced the supplied rod antenna with a larger, higher-gain RP-SMA antenna, mounted higher. That gained 4–7 dB at most; the gap remained.
  2. Antenna removed: no advertisements are received at all, so the antenna is in the signal path.
  3. Power: no RSSI difference between PoE and USB-C (5 V).
  4. Distance: moving a tag from a few metres to about 40 cm from the antenna improved RSSI by only about 2 dB, to −77 to −81 dBm.
  5. References at the same position: a Google Pixel 11 Pro (Ruuvi Station app), and a USB Bluetooth dongle with external antenna on the Home Assistant host (Realtek RTL8761BU, USB ID 0bda:8771).

RSSI comparison (dBm)

RuuviTag USB dongle (RTL8761BU) Pixel 11 Pro XIAO W5500
Indoors (≈40 cm) −38 −45 −77 to −81
Upstairs −74 −70 −97 to −99
Downstairs −74 −75 −102 to −103
Outdoors −76 −82 −97 to −101
Garage −86 −90 not received

The Pixel and the dongle agree within a few dB. The XIAO is consistently 25–40 dB weaker, which points to a fault in its RF path (U.FL connector, pigtail or module), not to range or configuration.

Questions

  1. Is weak Bluetooth reception known on V1.2 units? The early-batch RF issue discussed on the Home Assistant forum shouldn’t apply to a unit ordered in October 2026.
  2. Is there anything else you’d like me to test?
  3. If the unit is defective, how do I arrange a replacement?

Thanks!

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