Amateur Radio Direction Finding: ARDF and Fox Hunting Guide
Most of amateur radio is about sending signals as far as possible. Amateur radio direction finding turns that around: someone hides a small transmitter in a park or a forest, and you use a directional receiver, a map and your own legs to find it. The activity goes by several names, including ARDF, radio orienteering, radio fox hunting and radiosport, and it ranges from a relaxed club hunt on a Sunday afternoon to a serious international sport. This guide explains how it works, what equipment you need, how the formats differ and how to start with nothing more than a handheld and a directional antenna.
It is also one of the few corners of amateur radio where you can get a good workout, and where a beginner and an expert can compete in the same field.
What ARDF Is
ARDF stands for amateur radio direction finding. As the overview of the sport describes it, it is an amateur racing sport that combines radio direction finding with the map and compass skills of orienteering. It is a timed race in which individual competitors use a topographic map, a magnetic compass and radio direction-finding apparatus to navigate through wooded terrain while searching for radio transmitters. The rules of the sport and of international competitions are organised by the International Amateur Radio Union.
The sport originated in Northern and Eastern Europe in the late 1950s, where amateur radio was widely promoted in schools as a modern technical activity and radio direction finding had civil defence applications. One of the first recorded direction-finding hunts was held in Derbyshire in 1926. The first European Championship took place in Stockholm in 1961, and the first World Championship was held in 1980 in Poland. It remains most popular in Eastern Europe, Russia and China, with organised events in almost every European country and in places such as Australia, New Zealand, Canada and the United States.
How a Competition Works
An ARDF event takes place in a diverse wooded area, such as a public park or natural area, although some events have been held in suitable suburban areas. Each competitor receives a detailed topographic map showing the start, marked with a triangle, and the finish, marked with two concentric circles. Somewhere in the competition area the organiser has hidden five low-power transmitters, whose positions are secret and are not marked on the map.
Each transmitter sends a signal in Morse code so that it can be identified. The transmitters operate automatically, one after another, in a repeating cycle. Depending on the category, a competitor tries to find as many as three, four or all five of them and then runs to the finish line in the shortest possible time. Competitors start at staggered intervals and are individually timed. Results are decided first by the number of transmitters found and then by the shortest time, and competitors who exceed the time limit may be disqualified.
The key point for a newcomer is that the transmitters take turns. At any moment only one fox is on, so you cannot simply follow a continuous signal. You listen, take a bearing when your target is transmitting and move while the others take their turn. This is where Morse recognition helps. Our guide to learning Morse code and building CW speed is useful even if you only need to recognise the identification characters.
The Two Competition Bands
ARDF events use frequencies on either the 2 meter or the 80 meter amateur bands. They were chosen because they are available to licensees in every country. The two bands call for different equipment and different skills.
| Feature | 80 meters (HF) | 2 meters (VHF) |
|---|---|---|
| Equipment | Relatively simple and inexpensive to build | More complex and more costly |
| Bearings | Can be very accurate | Affected by terrain; reflections cause false bearings |
| Main skill | Taking bearings and planning the fastest route | Telling true bearings from reflections off hills, buildings and fences |
| Typical antenna | Loop with a sense element | Small Yagi or similar beam |
| Typical beginner choice | Good for learning the sport | Good if you already own a 2 meter radio |
Large national or international events usually include a day on each band. On 80 meters, you rely on accurate bearings and choose your own route through the terrain. On 2 meters, you learn to judge the quality of a signal: a strong signal that appears from the wrong direction is probably a reflection, and a bearing taken from a better spot may tell a different story.
Categories and Rules
All competitors in an event use the same area and listen to the same five transmitters, but they enter different categories based on age and gender. Under the IARU rules, only the open men’s category M21 must find all five transmitters. Other categories find four or five, or three or four, depending on age, so older competitors have fewer to find. Categories run from M19 and W19 for younger competitors through to M70 and W65 for older ones.
Youth competitions are open to competitors aged sixteen and younger, on shorter courses of up to six kilometres, with transmitters that may be closer to the start and a requirement to locate fewer of them. A World Youth ARDF Championship has been held every year since 2017.
The rules also address regulation. Because the foxes operate on amateur frequencies, a licensed amateur valid for the country of the event must be present and responsible for their operation. Individual competitors usually do not need an amateur licence, because simple handheld receivers do not typically require one. Regulations that forbid commercial use of amateur frequencies generally prevent cash prizes, so awards are medals, trophies, plaques or certificates.
What You Need: Equipment
The radio equipment carried on a course must be able to receive the signal of the transmitters and be useful for direction finding. According to the sport’s description, that means a receiver, an attenuator and a directional antenna, and most designs combine all three into a single handheld device.
Receiver
On 2 meters, a handheld FM receiver or a dedicated direction-finding receiver can be used. On 80 meters, a purpose-built receiver for the foxes’ frequency range is typical, because standard communications receivers are often too bulky for running through woods.
Directional antenna
A directional antenna provides the bearing. At 2 meters, a small Yagi-type antenna held at arm’s length is common. If you want to understand why directional antennas work, our guide to Yagi and hex beam antennas explains the principles, and our overview of 2 meter antenna designs shows how antennas differ at this frequency. On 80 meters, the small loop antenna with a sense element is the classic direction-finding choice.
Attenuator
The attenuator is more important than it sounds. As you approach a transmitter the signal becomes extremely strong, and a receiver without attenuation will overload, making the bearing broad and unreliable. An adjustable attenuator lets you reduce the signal so that you can still find the direction of maximum or minimum signal when you are close. This is the same overload problem described in our article on receiver dynamic range, blocking and IMD, applied to a very practical purpose.
Map and compass
A topographic map and an orienteering compass are as essential as the radio. Many events provide the map; learn to read contour lines, paths and vegetation boundaries.
Clothing and safety
You will be moving through uneven terrain, so wear suitable shoes and clothing, carry water and let someone know where you are going. Follow the event rules about safety whistles and time limits.
Direction-Finding Technique
- Start with a wide listen. At the start, turn slowly through a full circle and note where the signal is strongest and weakest.
- Take bearings from several places. A single bearing gives a line. Two or three bearings from different positions give an intersection that estimates the fox’s location.
- Use the attenuator. Reduce the gain as the signal strengthens so that the pattern stays sharp.
- Watch for reflections on 2 meters. A bearing that does not match the others, or that jumps as you move, may be a reflection. Move to a clearer spot and check again.
- Plan your route. On 80 meters, a good route can be worth more than raw speed. Think about paths, hills and obstacles on the map before you run.
- Do not forget the cycle. Know when your target will transmit again, and use the time between to move.
Practice makes a surprising difference. A club session with a few hidden transmitters in a local park teaches more in an afternoon than reading about it.
Informal Fox Hunts
Not all direction-finding events are formal sports. Many clubs organise relaxed fox hunts, in which one member hides a transmitter in a park or somewhere in town and others try to find it, either on foot or in cars. These events are an excellent introduction. They use ordinary 2 meter equipment, a simple beam antenna and a sense of fun, and they require no special competition rules.
If you want to start one in your club, keep it simple:
- Choose a legal frequency and make sure the transmitter operator holds the right licence for it.
- Use low power, and a transmitter that identifies itself according to your regulations.
- Pick a safe area, with agreed boundaries and a time limit.
- Give hunters a few clues, such as the general area, for the first event.
- Finish with a gathering so that people can talk about what they learned.
The sport’s governing bodies also provide training resources. The ARRL’s direction-finding page, for example, lists information on radio orienteering and describes an open-source 80 meter transmitter designed for classic, sprint and foxoring events.
Getting Started in Your Area
- Ask your club. Many clubs run occasional fox hunts, or know someone who does.
- Find your national society. The IARU has delegated ARDF coordinators in each region to help national societies and clubs start activities, especially in countries without prior experience.
- Borrow before you buy. Try someone else’s receiver and antenna before committing to equipment.
- Start with 2 meters. If you already have a 2 meter handheld, add a small directional antenna and an attenuator and join an informal hunt.
- Read the rules. If you move on to competitions, read the IARU rules and your national society’s local variations.
Safety and Etiquette
Because the sport takes place in woods and open country, a few common-sense rules matter as much as the radio skills. Always check the weather and the terrain before you go, and tell someone which area you will be in. Carry water, and a whistle if the organisers require one. Respect land boundaries, crops and wildlife, and leave no trace of the hunt. Do not run in areas marked as out of bounds, and never cross roads or railways without proper care.
Etiquette also matters on the air. Listen to the identification before you transmit anything, and keep any informal chatter off the fox frequencies. Some events limit what equipment can be used, so read the event rules in advance. After the event, share what you learned, including where the signals reflected and where the bearings were reliable. That knowledge helps the organisers set better courses and helps other competitors improve.
Common Mistakes
- Running before listening. Take a bearing first, and move with a plan.
- No attenuator. A receiver that overloads close to the fox gives a useless bearing.
- Trusting one bearing. Reflections can mislead you on 2 meters.
- Ignoring the map. The fastest straight line may be across a stream or a fence.
- Forgetting the cycle. The foxes take turns, and you must be ready when yours transmits.
The Bottom Line
Amateur radio direction finding rewards a mix of skills that few other activities combine: radio knowledge, map reading, physical fitness and patience. The formal sport follows international rules with five transmitters on 80 or 2 meters, while informal fox hunts need only a handheld, a small beam and a hidden transmitter. Start by joining a local hunt, learn to take clean bearings with an attenuator and a directional antenna, and build from there. You may find that the best way to understand how radio waves behave is to run toward them.
Frequently Asked Questions
What does ARDF stand for?
Amateur radio direction finding. The sport is also known as radio orienteering, radio fox hunting and radiosport, and it is governed internationally by the IARU.
Which bands are used for ARDF?
The 2 meter and 80 meter amateur bands, chosen because they are available to licensees in all countries. International events normally include a day on each band.
How many transmitters are there in an ARDF event?
Five low-power transmitters are hidden in the area. Depending on category, competitors must find three, four or all five.
Do I need an amateur radio licence to compete?
Generally not for the competitors, because simple handheld receivers do not usually require one. The transmitters, however, must be operated under the responsibility of a licensed amateur valid for the country of the event.
What equipment do I need to start?
A receiver, a directional antenna and an attenuator, often combined in a single handheld unit, together with a map and a compass. For an informal 2 meter hunt, a handheld radio and a small beam antenna are enough.
Why are 2 meter hunts harder than 80 meter hunts?
On 2 meters, signals are strongly affected by terrain and reflect from hills, buildings and fences, producing false bearings. On 80 meters, bearings are generally more accurate.