NRF24 Basic problem

if you load the channel scanner sketch it will test your basic hardware setup, you will need to align the CE and CSN pin definitions with your actual connections. If the library cannot connect with your NRF24 it will complain through the monitor, if you can see channel numbers then your hardware is probably okay. Normally channels above 100 are clear of routers etc. The command goes in the setup() function, you can see how to change parameters in the Basic TX/RX examples, you cannot change radio power with this library it is always set at max. Just of interest what micro-controllers are you using at each end?

But it moves the used frequency in a range above 2.5 GHz that may be forbidden,
depending on the country you're in.

Correct, channels have to be chosen with due regard to regulations.

That is one of the reasons that area is free of routers. :grinning:

What a radical thought, that area of the spectrum is quiet because unlicensed users are not allowed to transmit there.

In answer to your question I'm using an Arduino UNO from Sintron one end and a clone Arduino with a CH34 chip the other. Haven't had time to try the scanner yet, but will let you know the outcome when I do. Thanks for the help.

If you have the ATMega328 processor at either end you should have no problems with library compatibility, if not then expect some challenges. Good luck and feel free to come back. Are you in the USA?

No I'm in UK. Both Arduinos have ATMega328's I forgot to say that the clone is also a UNO.
I have now tried the ChannelScanner, and my NRFs seem to work ok on that, which is a good step forward. I get x's against channels 1-5, 25-28, 56-57, 77-82 although this varies slightly each time it is run.
However, I have no idea where these signals could be coming from - next doors wi-fi maybe?
My next step will be to try Robin2 2/63 simple tx rx test.