Increasing BLE Scan Range on nRF52840 BLE nRF Connect 1.8.0

[jake11212]

Hello,

I am using an nRF52840 as a central BLE gateway with nRF connect SDK 1.8.0.  I was looking for software changes to increase the scanning range.  So far I've found the bt_le_scan_param struct and changed its .options setting to BT_LE_SCAN_OPT_CODED which indicates that it is for long range use which has helped increase the range.  I was also wondering what difference scanning or not scanning on 1M phy would make, as it is another long range option (BT_LE_SCAN_OPT_NO_1M).  Does the coded PHY option from BT_LE_SCAN_OPT_CODED default to using 1M?  And if so what protocol is used if the BT_LE_SCAN_OPT_NO_1M is used?

I know that tx power is important but I've only seen it referenced on the advertising side, and assumed that it is handled in the bt_le_scan_param that I mentioned earlier, but wanted to make sure there wasn't anything else I was missing.

Thanks!

[Kenneth]

You may find answer 2 relevant from this this thread:
https://devzone.nordicsemi.com/f/nordic-q-a/86649/scanner-and-advertising-options-questions/362126#362126

In general the radio can only operate in one mode at a time (coded (optional) or 1Mbps (default enabled)), when you start scanning you can choose which to use, and the softdevice (BLE) controller will duty cycle/time divide the modes, such that it is possible to configure to use either coded or 1M, or both coded and 1M, though they do not actively occur at the same time.

Kenneth

[jake11212]

I changed my scan init to using .options = BT_LE_SCAN_OPT_CODED and added CONFIG_BT_CTLR_PHY_CODED=y to my config file.  Are these the only things I need to change the scanning to coded PHY?  

I tried testing with sdk 17.0.2 BLE_APP_UART running on a second board and saw some slight range increase, but wasn't sure if I was limited by the tx power of the BLE_APP_UART sample.  Are there any apps that are designed for testing range like this more precisely?

[Kenneth]

There have been various examples over time, I guess this is the latest one:
https://devzone.nordicsemi.com/nordic/nordic-blog/b/blog/posts/testing-max-range-with-ble-with-nrf21540dks-and-nrf52840-dks 

This is an older one:
https://devzone.nordicsemi.com/nordic/nordic-blog/b/blog/posts/testing-long-range-coded-phy-with-nordic-solution-it-simply-works-922075585 

Kenneth