ESB with different frequency

[Vlad Mokhnachov]

Hi! I have used NRF52832 on PCA10040. I want use several pair (master and slave) in one room. For this I try to select a different frequency for each pair. But, when I try to make this, I have some problem.

Case: one ESB master and one ESB slave. Master send always packet at channel 2 (2402 MHz). Slave listen each channel 25ms and after make a list of all frequencies with received packets and average RSSI.

• Channel = 1; Count Packet = 76; RSSI = 31
• Channel = 2; Count Packet = 79; RSSI = 23
• Channel = 3; Count Packet = 78; RSSI = 22
• Channel = 18; Count Packet = 3; RSSI = 80
• Channel = 50; Count Packet = 7; RSSI = 78
• Channel = 51; Count Packet = 1; RSSI = 78
• Channel = 66; Count Packet = 49; RSSI = 75
• Channel = 67; Count Packet = 20; RSSI = 73
• Channel = 90; Count Packet = 44; RSSI = 74

How it is possible? And what strategy of selecting channels can I used for normal working of all pairs?

[Hung Bui]

I think what butch suggested is correct. You use different channel and different address for each pair. Doesn't matter which pipe you use on each of the pair, it's the address (Base address 0 for example) that's matter. There will be crosstalk between channels. But if you use channels that's far enough from each other, you can reduce crosstalk. The signal on the correct channel on the receive will be stronger than the crosstalk signal from other channel.

You should also try to reduce the on-air time as much as possible to avoid interference.

If you use different address for each pair, there shouldn't be any crosstalk (but there still interference causing packet loss)