Would it be possible to build a miniature directional antenna that would work from
a Quadcopter? I'm thinking of doing an SDR radio (using a Raspberry Pi and a TV dongle). For the antenna, I was thinking of making a miniature version of the steel tape measure DF antenna, shown here:
http://www.instructables.com/id/Radio-Direction-Finding-Antenna-for-VHF/


Or should I just buy an antenna like this but be limited to 2.4 GHz?

http://www.balticnetworks.com/laird-antenna-12dbi-2-4ghz-mini-directional-antenna.html