Radio Orienteering

Amateur Radio Direction Finding (ARDF)

Welcome to Radio-O.  Here is how it works! We provide a radio receiver with a directional antenna, an orienteering map, a compass, and a finger stick. By pointing the antenna and listening to the signal you can determine the direction of the signal.  Using this information you navigate to the transmitter and punch in with your finger stick. Only the start and finish are marked on the map and it is important to keep track of where you are.  To qualify as finishing you must find at least one transmitter on your course and reach the finish within the time limit. To calculate results -- first; the number of assigned transmitters you found, then; your time on the course. We offer beginner through advanced courses, Regular BOK fees apply, and Pre-Registration is required.

Latest News in Radio Orienteering

September 20th, 2016

2017 International ARDF Champs in NC & The US ARDF Championship in Ohio

These events are in the planning stages, so check back for updates


International ARDF Championship in Asheboro, NC
July 24 – 28, 2017

BOK will host the International ARDF Championship event from July 24 – 28, 2017.  The event center will be at 1725 Gray Owl Road, in Asheboro NC.  The first day will be a training event focused on map reading.  The next four days will be: FoxOring, Sprint, 80 m and 2 m competitions.

We cordially invite our Sister Club, the Guangdong ARDF Radiosports Club and Radio Sport competitors of all levels from around the world to attend.

Participation costs are estimated at $10 per person per day.  All travel, lodging, and meals are the responsibility of the participants and are not included in the participation cost.  Hotels and restaurants are available in Asheboro, 15 minutes from Gray Owl.

Joseph & Ruth, Backwoods Orienteering Klub

2017 US Championship Ohio, July 31-August 6, 2017

Notes from the late July meeting in Cincinnati:
Please understand that these plans are subject to change, but we’re hoping to hold to the dates of July 31-August 6, 2017.

Our tentative dates are 31 July to 2 Aug 2017, for the training events, and 3-6 Aug being the championship events.

Still tentative, but a good bet:
Thur: Fox O
Fri: Sprint, model, competitor meeting
Sat: 2m Classic, Evening banquet
Sun: 80m Classic

Extremely speculative:
The thinking on the M-W practices is to start fairly early and finish in the early afternoon. It can rain anytime, but afternoon showers are likely on any given day. We’re hoping for an advanced track (probably two 3-4 km 5T events) and a beginner track with some instruction. Depending on who comes we can react to attendees’ needs. We’re thinking one park per day, or at the most two parks in one day that are very close together.


August 16th, 2016

Radio-O Courses Offered at BOK

Radio-O was born in Eastern Europe around the time of the First World War when commanders communicated with troops using radios.  When the radio was broadcasting you could get a bearing on the enemy.  So getting an accurate bearing quickly and careful map reading was important.

We offer 4 levels of Radio Orienteering.

  • Radio White 2-3 k – There are 5 numbered controls with transmitters that stay on all the time.  Each transmitter broadcasts on a different frequency.  You find the transmitters in the assigned order by tuning in the correct frequency and using the directional radio receiver to locate the controls.
  • Radio Yellow 2-3 k – The transmitter setup is similar to White, but you can take them in any order so in the beginning you can listen to all the signals to make a good decision.
  • Radio Orange 3-6 k – Again there are 5 transmitters coded 1-5, however, now they are all on the same frequency.  Each one stays on for a minute broadcasting its code and then shuts off so the next one can start.  After they all take a turn it starts over.  You take an assigned subset of the transmitters in the assigned order.
  • Radio Expert (Classic ARDF) 4-8 k – Similar to Orange except you have to determine the order and may be assigned more transmitters.

We also offer two other styles of Radio Orienteering.

  • Radio Sprint 2 k – One or two loops of 5 transmitters per loop.  All the transmitters on a loop are on the same frequency.  Each transmitter stays on for only 12 seconds before handing off to the next transmitter, so the whole cycle of  5 transmitters takes one minute.  Each loop is on a different frequency.
  • FoxOring 3-8 k – FoxOring has a stronger orienteering component because the approximate locations of the transmitters are marked on the map.  The transmitter and control may be as far as 100m from the location marked on the map.  As you approach the marked location you will be able to tune in the very low power transmitter to locate the control.  Like the others, you may not be assigned all the transmitters and your place is determined first by how many transmitters you found and then by your time.
August 14th, 2016

Radio-O at Carolina Forest 8/14/2016 Results

The event was a great success in that almost everyone found all the controls and had fun. In this White/Yellow level event there are 5 transmitters, each on a different frequency, transmitting continuously. There were a reasonable assortment of issues that make any ARDF event “unique”, shall I say.  We picked up a box of Chinese receivers […]

Read More
July 23rd, 2016

Radio-O Training Exercises

Map Reading – Line O

The map has a network of purple lines (that are not physical trails in the terrain) following the lines offer several route choice options to the transmitters.  Controls are set along the line and off the line at some key decision points.  Participants are instructed to only follow the lines to the transmitters, and to punch the controls that are on the line, but not to punch any controls that are not on the line.  Scoring:  one point for every correct control; negative two points for every wrong control (not on the line); ten points for each transmitter.

Taking Accurate Bearings

These exercises are done on blank “maps” that only have the participants location and north lines so that on multiple attempts to take bearings there are no clues as to where previous bearings were taken.  A fresh blank “map” is used for each new set of bearings.

Part I:  Transmitters are set out transmitting continuously on different frequencies and participants are instructed to take as much time as necessary to get accurate bearings.  The bearings are checked and participants are encouraged to try different techniques until they are able to consistently take reliable bearings.

Part II:  Using different transmitters from Part I, participants take careful bearings and then move to a new location to take cross bearings to locate transmitters.  Scoring is done by distance to the actual location.

In these exercises participants move about 5 meters between each set of bearings so that there are no hints from the terrain as to the angle of previous bearings

Taking Fast Bearings

Part I:  Five sprint transmitters are set out on a 1 minute cycle, and participants practice taking bearings to all five transmitters.  The goal is to get all five bearings accurate to five degrees, first in two minutes, and then in one minute.

Part II:  Participants take the 5 bearings in one or two minutes from two different locations to get cross bearings.  Three sets of bearings are taken on three different “blank” maps and scoring is done by the adding the total errors from the cross bearings to all the transmitters.

Blindfolded Radio-O: The Final 50 Meters

This exercise is a variation on “Blind ARDF”.  There are 3 transmitters, each with operators in an open area.  Participants are divided into teams of three people.  One person is blindfolded, and the first transmitter is turned on to run continuously.  The blindfolded one tries to locate the transmitter, while his teammates keep him from running into anything and keep him safe.  As soon as he is two meters from the transmitter he is told “next”, and the first transmitter is turned off and the second one turned on; this repeats with the second and third transmitters.  The groups rotate until everyone has had a chance running blindfolded and turning on and off transmitters.  Scoring is by the team with the shortest total time.

Course Planning

Different ARDF maps from competitions are displayed to the group and a the coach discusses various courses that could be set and the pros and cons of possible transmitter locations.  The coach takes suggested locations from members of the class and the suggestions are also discussed.  The goal of the exercise is to help the competitor assess the venue to make more intelligent decisions about route choice & possible locations.

Using Map Boards

People with different techniques show and explain how they use map boards.

  • Using a compass rose on the map board and degrees on your compass
  • Using reverse degrees on your compass
  • Attaching a compass to your receiver
  • Attaching a compass to your map board
  • Using a thumb compass
  • Using push pins to mark transmitter locations
  • Using wax pencils
July 24th, 2014

Birkhead International ARDF Competition and Training Camp Results

Birkhead International ARDF Competition July 20 – 23, 2014 These are the results from the 4 competitions we had in the Uwharrie National Forest.  This was a very successful cooperative event with the Guangzhou Radio Club.  One of the highlights of the event was how well we worked together and our declaration to become Sister […]

Read More