On Friday, 11 March 2016 12:53:11 UTC+2, Nick Hill wrote:
The default for RANGE if you
don't set it is 3Km for Classic Flarm. This limits the range of any
target on external displays.

I don't see 3km mentioned in that FLARM specification.
It specifies that the default horizontal range is 25500 meters for classic FLARM and 65535 meters for PowerFLARM.
Default vertical range is 500 meters for all FLARM device types.