Technical Information

The 2020 United States ARDF Championships will use radio transmitters on the 144 MHz and 3.5 MHz bands that will conform, as close as possible, to the technical specifications in the IARU Region I ARDF Rules Appendix 1: Technical Specifications for Amateur Radio Direction Finding Equipment. Competitors should be familiar with these specifications before they arrive at the competition. Some specific notes about this competition (subject to change):

  • 144 MHz: Mode A2A (AM keyed carrier). The control transmitter frequency will be 14x.xxx MHz and the homing beacon transmitter frequency will be 14x.xxx MHz. Transmitter antennas will be omnidirectional and horizontally polarized. All transmitters will identify with a call sign at the end of each one-minute transmission.
  • 3.5 MHz: Mode A1A (keyed CW). The control transmitters and homing beacon frequencies will be different for each event, but your receivers should be able to tune to 3.510 MHz, 3.530 MHz, 3.540 MHz, 3.570 MHz, and 3.579 MHz. Transmitter antennas will be omnidirectional and vertically polarized. All transmitters will identify with a call sign at the end of each one-minute transmission.
  • Map Details:
    • The maps for the practice events will be 8.5 x 11 inches (21.6 cm x 28 cm), landscape or portrait orientation, at 1:xxxxx scale with y (y) meter contours.
    • The map for the Fox Oring competition will be 8.5 x 11 inches (21.6 cm x 28 cm), landscape or portrait orientation, at 1:xxxxx scale with y (y) meter contours.
    • The map for the Sprint competition will be 8.5 x 11 inches (21.6 cm x 28 cm), landscape or portrait orientation, at 1:xxxxx scale with y (y) meter contours.
    • The map for the 144 MHZ Classic Distance competition will be TBD dimensions, landscape or portrait orientation, at 1:xxxxx scale with y (y) meter contours.
    • The map for the 3.5 MHz Classic Distance competition will be TBD dimensions, landscape or portrait orientation, at 1:xxxxx scale with y (y) meter contours.
  • Time keeping: Clocks synchronized to a WWVB time standard will be present at both the start and finish areas. All competitors will use SportIdent for recording their time on course.