I tried 100 uf capacitors, different arduino boards and power supply. None of them worked so I bought 2 more NRF24L01+PA and to be sure that power is not the problem bought adapter board for them. But they are not working eighter. I don't know where I am mistaken.
Robin2's simple rf24 tutorial was very helpful in getting my rf24 radios to work. There is a sketch that will help to confirm the physical wiring of the rf24 modules to their respective processors. See reply #30.
The external antenna radios may need to be separated by a few meters in order for them to communicate. If they are too close together they might not work.
I have 2 Arduino uno and 2 Arduino nano. I tried many combinations with them unfortunately found no solution.
Might be hardware problem, that test for connections which in Robin2's simple rf24 tutorial, does also determines if there is hardware problem? So should I look for new Arduinos or is there change that nrf24 s might have hardware problem?
I have 2 raspberry pi 3b+, I can try nrf24 s with them too. Do you know any good and basic tutorial to try?
Robin2's tutorial very definetly works, as do the examples in the NRF24 library, when the modules are connected correctly.
I had a pile of el-cheapo NRF24s, bought on eBay, Aliexpress etc. I had around 12 and when I started testing them I could not get them to work. Eventually I had a pair that did work, and when I went through them all I binned 50% of them as not working.
I have not seen any evidence that a non working NRF24 has been 'fixed' by some individual magic change to a library or example.