An example of BLE 5 extended advertisement scanner with Bleak-Bumble

July 11, 2026 · View on GitHub

Using an RTL8761B as scanner and another RTL8761B or Zephyr HCI-USB as advertiser

Bleak-Bumble scanner / observer successfully worked with RTL8761B dongle (UB500, TP-Link, with fw 0xddd5c761) in receiving extended advertisements (LE_1M_PHY and LE_CODED_PHY S=2 / S=8) sent from Bumble advertiser / broadcaster.

python examples/le_ext_adv_scanner.py
 ...

 BLEDevice(F1:F2:F3:F4:F5:F6, Bumble) with AdvertisementData(local_name='Bumble', manufacturer_data={65535: b'THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG.0123456789the quick brown fox jumps over the lazy dog.0123456789'}, tx_power=127, rssi=-12)

 ...

Because Coding Scheme Selection on Advertising (CSSA) introduced in Bluetooth 5.4, which allows to specify the coding parameter S, is not supported in Bumble host and in my bluetooth controllers yet, two different controllers have to be used for S=2 and S=8 in LE_CODED_PHY. An RTL8761B (another UB500) and a Zephyr's HCI-USB (Xiao nRF52840), respectively, were used for S=2 and S=8 codings. In all of the cases, advertisement packets were confirmed by nRF BLE sniffer (Nordic's nRF52840 dongle) and Wireshark.

Scanner/Observer	Advertiser/Broadcaster	PHY	Result
RTL8761B	RTL8761B	1M	works
RTL8761B	RTL8761B	CODED (S=2)	works
RTL8761B	RTL8761B	CODED (S=8)	-
RTL8761B	Zephyr HCI-USB	1M	works
RTL8761B	Zephyr HCI-USB	CODED (S=2)	-
RTL8761B	Zephyr HCI-USB	CODED (S=8)	works

Notes:

Because CSSA is introduced in Bluetooth 5.4, the latest dongles ~~such as RTL8761C~~ may work.
An RTL8761CUV dongle has been bought and tested, only to fail in using LE_CODED_PHY. Receiving extended advertisements in LE_1M_PHY/LE_2M_PHY and changing from 1M to 2M and v.v. during connection worked perfectly though. I was not aware that RTL8761C lacks LE_CODED functionality before I bought it; should have seen the datasheet.
HCI_LE_Set_Extended_Advertising_Parameters_V2_Command for CSSA is not yet fully suported in Bumble (as of 0.0.230).
Zephyr's HCI-USB firmware was built for my Xiao nRF52840 (with bootloader) by using Zephyr-RTOS (v4.4) and Zephyr-SDK (v1.0) as follows:

west build -p always -b nrf52840dongle samples/bluetooth/hci_usb \
 -DCONFIG_FLASH_LOAD_OFFSET=0x1000\
 -DCONFIG_BUILD_OUTPUT_HEX=y\
 -DCONFIG_BT_EXT_ADV=y\
 -DCONFIG_BT_EXT_ADV_LEGACY_SUPPORT=y\
 -DCONFIG_BT_EXT_ADV_MAX_ADV_SET=2\
 -DCONFIG_BT_CTLR_ADV_EXT=y\
 -DCONFIG_BT_CTLR_ADV_DATA_LEN_MAX=191\
 -DCONFIG_BT_CTLR_SCAN_DATA_LEN_MAX=191\
 -DCONFIG_BT_BUF_ACL_RX_SIZE=502\
 -DCONFIG_BT_BUF_ACL_TX_SIZE=502\
 -DCONFIG_BT_CTLR_DATA_LENGTH_MAX=251\
 -DCONFIG_BT_DATA_LEN_UPDATE=y\
 -DCONFIG_BT_CTLR_ADVANCED_FEATURES=y\
 -DCONFIG_BT_CTLR_CONN_RSSI=y\
 -DCONFIG_BT_CTLR_TX_PWR_DYNAMIC_CONTROL=y

Although Xiao is cheap, easily available and convenient for a quick test like this, I do not recommend to use it in real BLE5 applications because of its poor antenna.