This special Callsign is activated by a group of members of Bulgarian Federation of Radio Amateurs - ARDF Club.

LZ5F operation (printing and sending QSL cards) is sponsored by ELECTRONINVEST Ltd. , Victor Tzenkov LZ3NN (Bulgarian ARDF manager) - http://www.electroninvest.com and http://www.electron-gps.com

Amateur Radio Direction Finding (ARDF) is the sport of finding radio transmitters on foot, using radio receiver, map, and compass in diverse, wooded terrain. ARDF joins orienteering skills like the proper use of topographic maps, compass skills, and locational awareness, with radio direction finding skills using hand-held portable receivers and antennas. It is great fun for young and old alike - an opportunity for personal challenge in the great outdoors!

http://en.wikipedia.org/wiki/Amateur_Radio_Direction_Finding

http://www.ardf-bg.com/

http://ardf.ru/ - in Russian

http://www.homingin.com/

http://www.youtube.com/watch?v=UPLWCc_rDqk

http://www.2008ardf.org/

http://www.ardf-r2.org/en/

http://offcycle.org/index.php?option=com_frontpage&Itemid=1

LZ5F is member of Digital Modes Club - DMC #1275 - http://www.digital-modes-club.org