I would like to get the longest range / most stable WiFi link possible on my PixRacer. The WiFi has a board antenna with no connection for an external antenna.
Is it possible to seamlessly swap this out with another WiFi board that supports an external antenna or higher powered module?
Not sure what “seamless” means to you but there are ESP8266 boards with a u-fl connector (ESP-07 for example) for use with an external antenna. But the range will still not be great. These radios are really only good for general configuration and calibration purposes. I have them on multirotors, a plane and a Rover for that purpose.
A late answer but maybe it is still an actual item.
I have thought about the same question and just replaced the standard Esp8266 WiFi card with an ESP8266-07 with an external antenna. I have also installed a USB WiFi adapter with an external antenna to my laptop.
I managed to get the ESP-07 working today so still do not know what range to expect but I am glad if it shifts from lousy to at least bad or better 
If weather permits I will test it during next week.
Hello
Tested with UBIQUITY NanoStation M2 as AP and various ESP modules and antennas.
Range is good (about 1 Km), depending on the local noise background (vehicle, RC and neighboor AP)
Dont forget to desolder and resolder jumper from internal to external antenna 
Hi,
Thank you for the info.
I have not been able to test distances as far as 1 km but with an Esp-07 (with external antenna) on the drone and a Netgear A6210 WiFi USB adapter for the laptop there have not been any problems with distances 300 - 500 m over an open area. This is a very large improvement because earlier the communication failed already at 30 - 50 m.
