I have not seen documented how to specify a channel away from other busy/noisy channels. Example appreciated
Depends on what firmware your ESP module is running.
You'll also want to read https://blog.falafel.com/esp8266-wi-fi-channels/
Your answer pre-supposes that he is running the ESP8266 Arduino Core.
Thanks for quick responses. YES I'm running with the ESP8266 Arduino Core.
My current project is trying to get a 01 working over 15 metres but through a double course brick wall and metal garage roller door back to my home modem router. This is working OK but with dropouts every 30 minutes or so. Obviously I'm getting to the limits of possibilities but I have been able to get the reliable data through to Thingspeak by using a watchdog function with ESP.reset() utilizing the ticker.h library.
I'm also now trying to modify the performance of the PCB antenna as described in the follow 2 links which relate to NRF24L01 RF units which operate at same 2.4GHz frequencies.
I'll post back my results for 'others' who may be interested
I've got some EDP-07 modules, they have an external antenna connector, so the range is pretty good. (Using laptop antennas or just a straight 2.4GHz antenna.)
You can get them from eBay for less than $3. Make sure you order a breakout board as well.