Signal range extension

Hi Robert,
Superb set of suggestions, many thanks.
1- The option of extending the aerial, is there a limit on how long the extension cable can be? And is it just a simple matter of striping the end of existing aerial cable on emonTx and joining it up with a similar cable? I can extend the aerial cable by about 10m and then it will be in the direct line of sight of the RPi basestation, but I wonder if 10m of additional cable might present any problem?
2- I don’t know if the RPi is Wi-Fi enabled. It is powered by a micro-USB power input and has 4 standard USB port, a LAN port, a HDMI port, and what looks like a video/audio port.
I would love to hear your thoughts particularly on point 1.
Best wishes from a cold and cloudy Newcastle
M