Transcription of ARDF - BVARC
1 ARDFA mateur Radio Direction Finding(Fox Hunting) International Style Thomas KrahnKT5TK / DL4 MDW Fox Hunting Should this be stopped? ARDF International Rules Find 5 hidden transmitters by using a portable receiver with a directional antenna The foxes must be found before a maximum time limit. Ranking: 1.) Number of foxes in time limit. 2.) Time at finish line The transmitters are under time control. Each TX sends for one minute its ID, then the next fox is switched on. (5 minute total cycle) Typically used: 80 m CW Morse code,2 m AM modulated Morse code ARDF Fox IDs MOE . MOI .. MOS .. MOH .. MO5 .. Long dashes good for direction finding Count the dots to know which fox it is ARDF Frequencies 80 m: MHz (NTSC color carrier frequency) 5th fox sometimes on different frequency (homing fox) 2 m: MHz (Europe), MHz (official IARU region II) ARDF Transmitters Control logic usually micro-controller Time synchronization of all 5 foxes difficult TX power 1 5 Watts 2 m: Antenna cross dipole 80 m: Grounding wires, Tent pegs, 50 ft wire Close to the transmitter good visible flag and punch station.
2 ARDF Transmitters ARDF Receivers 2m Water Level HousingLong VersionTraditional German VersionPhotos by DF1FO ARDF Antennas 2 m2 Element HB9CV4 Element Log Periodic3 Element YagiRussian VersionMoxon RectanglePhotos by DF1FO ARDF Receivers 80 m ARDF Receivers 80 mDF1FO 20101947SM5IQ 1953WB6 BYU QST 9/2005VK8 YNGOE6 GCPJ-80 ARDF Antennas 80 mFrame Antenna:10 wire cable in circular aluminum tubeforming a coil. Circular tube must havean isolated gap! 6 dB more sensitive than ferrite rodsPhotos by DF1 FOFerrite Rods:longer = betterWatch out for surplus bars withfurrows!Not all ferrite bars work at MHzSelect by try & error only ARDF Orientation Gear GPS usually not allowed Compass Map Appropriate sport clothing Sturdy shoes Carry some drink Rope your glasses around neck ARDF Strategy Start with the fox with the loudest signal Plan a round course (No zigzag) Make sure to watch the clock and arrive at the finish line before the max.
3 Time Do not trust other fox hunters If there are hills, always choose a route on the top of a ridge. Careful with reflections in valleys ARDF Competitions 28-30 May 2011 Shropshire ARDF FestivalLudlow, England, UK 5-10 september 201118th IARU Region I ARDF ChampionshipsOradea, Romania 16-18 september 20116th IARU Region II ARDF ChampionshipsAlbuquerque, New Mexico 23-28 september 20115th IARU Region III ARDF ChampionshipsVictoria, Australia september 201216th World ARDF ChampionshipsSerbia september 201417th World ARDF ChampionshipsAstana, Kazakhstan ARDF Web Links
