Frequencies & Equipment
8d2.
Describe what frequencies and equipment are used for ARDF or fox hunting.
ARDF Frequencies
International ARDF competitions use two frequency bands:
| Band | Frequency | Wavelength | Characteristics |
|---|---|---|---|
| 80 meters | 3.5 MHz | ~80 meters | Signals bend around obstacles; useful in dense forest. Harder to get precise bearings. |
| 2 meters | 144 MHz | ~2 meters | Line-of-sight propagation; sharp, precise bearings possible. Blocked by hills and buildings. |
80 meters
- Frequency
- 3.5 MHz
- Wavelength
- ~80 meters
- Characteristics
- Signals bend around obstacles; useful in dense forest. Harder to get precise bearings.
2 meters
- Frequency
- 144 MHz
- Wavelength
- ~2 meters
- Characteristics
- Line-of-sight propagation; sharp, precise bearings possible. Blocked by hills and buildings.
For informal club fox hunts, any VHF or UHF frequency may be used — commonly 146 MHz (2 meters) or 440 MHz (70 cm).
Equipment
Receiver
A sensitive receiver that can tune to the fox’s frequency. For 2-meter hunts, a standard VHF handheld transceiver (HT) works. For 80-meter hunts, a dedicated shortwave receiver is needed. Many ARDF competitors use purpose-built receivers with an attenuator (a control that reduces sensitivity as you get closer to avoid signal overload).
Directional Antenna
The key piece of equipment. Common types:
- Yagi antenna (2 meters) — looks like a TV antenna with parallel elements on a boom. Gives a strong, directional signal pattern. You swing it side to side to find the direction of strongest signal.
- Tape-measure Yagi — a popular DIY version made from steel tape measures. Lightweight and collapsible.
- Loop antenna (80 meters) — a small loop of wire or tubing. Uses the antenna’s natural null (minimum signal direction) to determine bearing. Nulls are sharper than peaks, so loop antennas find direction by pointing toward the weakest signal.
- Adcock antenna — a pair of vertical elements used for 80-meter DF work.
Other Gear
- Compass — for taking bearings once you determine signal direction
- Map of the hunt area — for plotting bearings and planning routes
- Attenuator — essential for close-range work; without it, the signal is so strong near the fox that your antenna can’t determine direction
- Comfortable shoes — you’ll be walking or running through terrain