VLF metal detectors dominate the treasure hunting market for good reason. These affordable entry-level detectors and advanced models alike rely on continuous sine wave technology that's been refined over decades.
How VLF Continuous Sine Wave Technology Works
VLF (very low frequency) detectors create an electromagnetic field transmitted into the ground as a continuous wave. This field oscillates at frequencies typically between 3-30 kHz, which is why they're called "very low frequency" compared to radar or radio waves.
The transmit coil sends out this continuous sine wave, creating an electromagnetic field that penetrates the soil. When this field hits a metallic object, it induces eddy currents in the metal. These currents create their own electromagnetic field that opposes the original field.
The receive coil detects changes in the electromagnetic field caused by these eddy currents. Your detector's signal processing circuitry analyzes these changes to determine target presence, depth, and often the type of metal.
VLF vs Other Metal Detector Technologies
Unlike pulse induction detectors that send short bursts of energy, VLF detectors maintain a constant electromagnetic field. This continuous operation gives VLF units several advantages:
- Better target discrimination between different metals
- Superior performance in mineralized soil when properly ground balanced
- Lower power consumption than PI detectors
- More precise target identification
The trade-off is reduced depth capability compared to pulse induction units, especially on larger targets.
When VLF Technology Excels
VLF detectors perform best in these situations:
- Coin shooting in parks: Excellent discrimination separates coins from trash
- Relic hunting: Target ID helps identify iron relics vs valuable finds
- Jewelry hunting: Good sensitivity to small gold items
- Freshwater detecting: Ground balancing handles mineral content
VLF Limitations
Highly mineralized ground can challenge VLF detectors. Black sand beaches and red dirt with high iron content may require frequent ground balancing or switching to a pulse induction detector.
Salt water also poses challenges for most VLF units, though some models like the Minelab Equinox series handle mild saltwater conditions well.
Choosing Your First VLF Metal Detector
New detectorists should consider beginner-friendly VLF models that balance performance with ease of use. Look for detectors with:
- Automatic ground balancing
- Pre-set search modes
- Clear target ID displays
- Lightweight design for extended hunting
The Garrett detector lineup offers excellent examples of refined VLF technology across different price points.
Frequently Asked Questions
Are VLF metal detectors good for treasure hunting?
VLF detectors excel at treasure hunting in most environments. Their discrimination capabilities help separate valuable targets from junk, making them ideal for coin shooting, jewelry hunting, and relic detection.
What's the difference between VLF and PI metal detectors?
VLF detectors use continuous sine waves and offer better target discrimination. PI detectors send short pulses and achieve greater depth but provide less target information. Choose VLF for discrimination, PI for maximum depth.
Whether you're starting with a budget-friendly detector or investing in professional equipment, understanding VLF technology helps you make informed decisions and get better results in the field.
