Hi folks,
I am working with custom board based on the nrf52832 as a peripheral, and using a nrf52840dongle as the central. Running on ncs2.1, we support up to 5 (maybe more in the future) peripherals talking to the central at one time but for the purpose of the below testing some of it was done with 1 central and 1 peripheral.
During testing we noticed that the range is not as good as we would like it to be so we tried a few things. We drop a connection once the peripheral range is about 4-5 metres away from the central and its much worse if there is a person in the direct line of sight path from central to peripheral.
1. Using an nrf52840dk as the central instead of the nrf52840dongle. This had a pretty significant improvement over the dongle
2. Using an nRF52 as the peripheral; we get a decent improvement in range
3. Reducing from 2M PHY to 1M PHY; this has a marginal but noticable improvment in range
4. Adding an external antenna to the nrf52840dk; this had a minor improvment in RSSI
5. Using the fanstel ev-bt840xe as the central which contains a power amplifier; very minor improvement in RSSI over the nrf52840dk
6. Adjusting the TX power to +8dB and +4dB (using CONFIG_BT_CTLR_TX_PWR_PLUS_*) for central and peripheral respectively; this did not seem to make a discernable difference
Things we havent tried but would likely help
7. Use coded PHY; the nrf52832 does not support this
It seems the custom board offers the worst performance when compared against other nrf52832 devices (mainly a nrf52dk) as peripheral. In addition to that the dongle offers worse performance than the 52840dk as the central. This is sort of expected because the DKs likely have a much larger antenna.
Short of redesigning the antenna on the custom board, which is not something we can easily do at this time, is there anything we can try from a configuration perspective to improve the range?
