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Radio Society of Great Britain IARU ARDF Rules Overview of Formats
The Sprint format has much shorter transmissions from each of ten transmitters on two different frequencies. There is a spectator beacon that has to be visited after finding the first five of the ten transmitters. This format is fast and furious and has a greater spectator appeal.
The final format is FoxOring. This is half way between Radio Direction Finding and Orienteering.
Competitions for the Blind are also organised. These take place in an area about the size of four tennis courts with a surrounding fence. Competitors are accmpanied but have to locate the transmitters unaided
Classic Races
Competitions take place on either the 3.5 or 144 MHz bands. Each transmitter is allocated a one minute slot. During this time it sends its ID in morse, but before you personally switch off, this is not a problem to anyone who does not know any morse. The transmitters are identified by the letter sequences MOE, MOI, MOS, MOH, and MO5. In morse MOE comes out as 'dah dah, dah dah dah, dit'. Click here for an audio clip of MOI which is 'dah dah, dah dah dah, dit dit'. To distinguish them, all you have to do is to count the dots at the end and the M and the O form a clear intro. Hence, the first Tx in the sequence has one dot at the end of its call, the second has two dots, the third three dots and so on.
The sixth transmitter is a beacon transmitter which is on the air continuously on a different frequency. If you get totally lost then just DF this beacon to find the finish. Both frequencies are given out before the start and you may wish to have them written on your receiver as a reminder. Siting of Foxes
Transmitters cannot be placed nearer than 750 m of the start and 400 m of the finish. Also, the transmitters must be at least 400m from each other. The map you are given at the start has only the start and finish marked. In domestic competition, with the small forested areas widely available in the UK, the 750m limit is usually reduced to 400m
Classes of Competition
The existence of several classes makes the sport enjoyable for all ages. In the table below, ages count from January 1st of the year in which you attain the age e.g., a man whose 60th birthday is 26 August 2003 is allowed to compete as an M60 from 1 Jan 2003. This arrangement means that competitors do not change class in mid-season.
The M21 class has to find all five transmitters. The number of transmitters to be found by other classes is at the discretion of the siting referee. Generally, the older the competitor, the fewer transmitters have to be found.the identity of the transmitters to be found by any each competition class are announced before the start. The M/W21 age groups have no restrictions on the ages of the competitors. M/W19 apply to the end of the calendar year in which you become 19. An M40 enters this category on the 1st January of the year in which he becomes 40 and similarly with M50, M60, M70, W35, W50, W60. Prevention of Cheating
Dress There are no specific rules about dress. Some people wear orienteering clothing but for the majority a variety of dress is seen. Basically, anything you are comfortable in for walking (mostly) and occasionally jogging in the woods. Safety Take a whistle and remember that the emergency signal is 6 blasts followed by a one minute interval then 6 more blasts and so on. Time Limit There is a time limit to the competition, usually 90 minutes or two hours. If you find all the Txs but are just one second over the time limit you will be placed below anyone who is within the time limit but who has found only one Tx. Pretty galling! So make sure you have a watch and use it to ensure you are not out of time. The time limit is announced before the start. The Sprint Format Foxoring Competitions for the Blind |
These five transmitters are placed in the competition area which is accessible only on foot. Each transmitter is concealed to some extent but is marked with an orienteering style red and white 'kite' marker to which is attached an orienteering needle punch which must be used to punch the control card you carry as proof of finding the Tx. In important competitions, the transmitters will be 'manned' in the sense that they are under observation.
To stop people taking furtive bearings before they start, all receivers and all competitors are separately corralled before the transmitters come on the air. The photo shows some Dutch 80m receivers laid out in the designated area. You are not allowed to communicate to anyone outside the corral.This can lead to a long wait in a big competition since starts are at 5 minute intervals. You are allowed to collect your receiver as you move into the start corridor but can only switch it on after you start. It is your responsibility to provide weather protection for your receiver while it is kept in the corral. You also need to be able to tune your receiver accurately to the stated frequency.