Picture this: you're hunting an old park and every few seconds your detector screams over another pull tab or bottle cap. Your finds pouch fills with junk while coins stay buried. That's exactly when notch discrimination becomes your best friend.
Notch filter discrimination lets you selectively silence specific conductivity ranges on your metal detector's discrimination scale. When you notch out a segment, metals with that conductivity level won't produce an audio response or visual indication. The detector still senses them, but ignores them completely.
How Notch Discrimination Works
Most metal detectors display targets along a conductivity scale, typically numbered from 1-99. Low numbers represent metals like iron and foil (around 1-15), mid-range covers pull tabs and small gold (20-35), while high numbers indicate silver and copper coins (70-90).
When you activate notch discrimination on a specific segment, your detector masks any target reading in that range. The electromagnetic field still detects the object, but the control box suppresses the audio and visual alerts.
This differs from standard discrimination, which progressively eliminates everything below a certain threshold. Notch discrimination creates precise "holes" in your detection pattern.
Common Notch Discrimination Patterns
Experienced detectorists develop go-to notch patterns based on hunting conditions:
Park and School Patterns
Notch out pull tabs (25-35 range) while keeping nickels (20-25)
Eliminate bottle caps (35-45) but preserve quarters (75-85)
Block foil (1-15) to reduce constant chatter
Beach Hunting Setup
Accept wider ranges since salt conditions affect readings
Minimal notching to avoid missing gold jewelry
Focus on eliminating obvious iron signatures
Relic Hunting Configuration
Accept most iron for buckles and artifacts
Notch modern trash like aluminum cans
Keep wider acceptance patterns for varied target conditions
Advanced Notch Discrimination Techniques
Modern Minelab metal detectors and other premium brands offer sophisticated notch capabilities that go beyond basic segment blocking.
Multi-Frequency Benefits
Multi-frequency detectors provide more accurate target identification, making notch discrimination more reliable. They separate targets that single-frequency units might lump together on the conductivity scale.
Smart Notching Strategies
Instead of notching large ranges, create narrow rejection windows. A 3-point notch around pull tab signals (27-29) often eliminates most tabs while preserving small gold rings that might read slightly higher or lower.
Test your notch patterns with known targets before heading out. Drop coins, jewelry, and common trash items to verify your settings work as intended.
When NOT to Use Notch Discrimination
Notch discrimination isn't always the answer. Skip heavy notching when:
Hunting for gold jewelry - too much overlap with trash signals
Searching virgin ground with minimal trash
Relic hunting where iron artifacts have value
Learning a new detector - dig everything initially to understand target responses
Notch Discrimination vs Full Discrimination
Standard discrimination eliminates everything below a set point on the conductivity scale. Set discrimination to 40, and you'll reject everything from 1-40. This creates a clean separation but eliminates potentially valuable targets in the rejected range.
Notch discrimination offers surgical precision. You can reject specific problem targets while keeping everything else active. This flexibility makes it superior for most detecting situations.
Detector-Specific Notch Features
Beginner and intermediate metal detectors typically offer 2-8 notch segments. High-end units provide 50+ individual notch points for precise target filtering.
Some detectors remember multiple notch patterns, letting you switch between park, beach, and relic programs instantly. Others require manual setup each time you detect.
Troubleshooting Notch Discrimination Issues
Missing Good Targets
If you're passing over coins or jewelry, your notch windows might be too wide. Ground conditions, target depth, and orientation all affect conductivity readings. A coin reading 78 at 4 inches might register as 72 at 8 inches.
Inconsistent Target Response
Targets near notched ranges may produce broken or choppy audio. This often indicates a good target affected by nearby iron or challenging ground conditions. Investigate these iffy signals - they frequently turn into keeper finds.
Maximizing Your Notch Settings
Start with minimal notching and add rejections based on actual trash encountered. Each hunting site presents different challenges, so cookie-cutter patterns rarely work perfectly.
Keep a log of conductivity readings for found items. After 50+ targets, you'll see patterns emerge that help refine your notch discrimination settings for maximum effectiveness.
Quality metal detector accessories like larger coils or different frequencies can also change how targets register, requiring notch pattern adjustments.
Remember: notch discrimination is a tool, not a crutch. The best finds often come from investigating questionable signals that other detectorists skip. Master your notch settings, but don't become a slave to them.
