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 15th, 2021

2021 US & Region II ARDF Championships Bulletin 2

Everyone is welcome at the 2021 US & Region II ARDF Championships.

Bulletin II is now available containing all the necessary event information.

View Bulletin 2 as a Google Doc

View Bulletin 2 as a published web page.

(Changes to the Bulletin will be posted here & in the Bulletin if/when they occur.)


9/19/21 Things to do in Asheboro added to the end of Bulletin 2.


Location: Durham, NC for the practice events and Asheboro, NC for the Championship Events

  • Practice Events
    • October 10-12, 2021
  • Championship Events
    • October 14-17

Everyone is welcome to participate. There will be awards for US Champion, Region II Champion and Overall.

Registration for the Championship Events is at EventReg.OrienteeringUSA (BOK current Annual Pass holders can enter “BOK” for a $7 discount coupon on the “Summary Page”.)

Registration for the three Practice events is at BackwoodsOK.org/Store When registering for the Carolina North event choose the event with your preferred arrival window.

All participants must be fully vaccinated against Covid and wear masks when approaching event volunteers.

September 14th, 2021

2021-09-12 – ARDF 2m Classic, Eno River State Park — Results.

Nine participants came out run the course. It was exciting to try Charles’ 2m transmitters in a rugged environment. There was much discussion of how reflections might come out differently with different antenna types, how power levels and terrain affected readings, and different techniques for figuring out where transmitters are given some misleading signals. Ah, […]

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September 8th, 2021

Open Radio-O/ARDF 80m & 2m CNF – Results

We had wonderful weather. Eight participants came out to run the course. With the centrally located start, we expected many different course choices. It was fun afterward to hear how participants planned their runs. In addition to the complexity of the course, several participants went on both the 80m and 2m course, adding exhaustion to […]

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September 6th, 2021

Open Radio-O/ARDF event at Carolina North Forest, Sep. 5.

We will have an 80 m classic course at Carolina North Forest on September 5, Sunday. Park at the end of Municipal Drive (GPS 35.9365 -79.0661, Google maps link). Then follow the BOK signs to pick up your map. There is a five minute walk from the pick-up area to the start. For more information about Radio-O/ARDF, see the BOK ARDF page.

Start times. Pre-registration to a particular start window is required. There is no need to sign up for a particular course. Everyone gets the same map. Please register before Friday Sep 3. Starts are available from 10 AM to 2 PM. The course closes at 3 PM.

The 80m course.

  • The homing beacon is the finish. There is only one control to punch at the homing beacon and it is the finish. There is no finish shoot.
  • There is a 400m exclusion zone around the start and around each control.
  • Foxes will be on 3.53 MHz,
  • Homing beacon on 3.55 MHz.

80m Course distances.

level distance
1 fox 1.4 km
2 foxes 2.0 km
3 foxes 3.3 km
4 foxes 4.4 km
5 foxes 5.0 km

Charles is also putting up a 2m course for those who want an extra challenge.

2m Course Details

The 2m course will operate concurrently with the 80m course with the same start time and course closure time. The start and finish for the 2m course are the same as for 80m, with the same exclusion distances. The course lengths will be similar to those of the 80m course and will be provided to those who would like that hint.

  • Fox Frequency: 145.55 MHz;
  • Finish Beacon: 145.75 MHz;
  • Transmit Power: ~350 mW;
  • Antenna type: Eggbeater omnidirectional horizontally polarized;
  • Classic course: 5 foxes + finish beacon.

These are the effective course lengths:
(effective course length is straight line distance plus 10 times the climb)

  • Find All Five – 6.7 km
  • Find 1,2,4,5 – 5 km
  • Find 1,2,3 – 4.2 km

Event directors: Patrick & Kelly

September 6th, 2021

Open Radio-O/ARDF 2m Classic at Eno River State Park, Sep. 12.

We will have an 2 m classic course at the Eno River State Park Few’s Ford Access on Sunday, September 12, GPS 36.0742 -79.0055. For more information about Radio-O/ARDF, see the BOK ARDF page. Starts 10:00 AM to 1:00 PM. The course closes at 3:00 PM.

Registration.
Pre-registration to a particular start window is required. There is no need to sign up for a particular course. Everyone gets the same map. Please register by the end of the day, Friday Sep 10. Link for the registration.

Receiver loans.
If you need a 2m receiver, you will need to check that box on the registration page. We only have 6 to loan.

The course.
The homing beacon is the finish. There is only one control to punch at the homing beacon and it is the finish. There is no finish chute. There is a 300 m exclusion zone around the start and around each control.

  • Fox frequency: 144.300 MHz.
  • Finish beacon frequency: 145.550 MHz.
  • Transmit power: ~350 mW
  • Antenna type: Eggbeater omnidirectional horizontally polarized

Course distances. These are as the crow flies and Eno has quite a bit of elevation change.

level distance
1 fox 1.5 km
2 foxes 2.3 km
3 foxes 2.6 km
4 foxes 3.2 km
5 foxes 4.1 km