Search Coil Sizes Guide: When to Use Different Coils

Serious Detecting Marketing
2024-07-12T17:00:02-04:00

Choosing the right search coil size can make or break your detecting session. Most detectorists stick with their stock coil, but switching between small, medium, and large coils based on your hunting conditions will dramatically improve your finds rate and target recovery.

The Garrett ACE APEX ships with an excellent 6" x 9" DD coil that handles most situations well. But understanding when to swap coils - and having the right ones in your kit - separates productive hunters from those who struggle in challenging terrain.

Small Coils: Precision in Trashy Areas

Small coils (4" to 6" round) excel in nail-infested areas where larger coils get overwhelmed. They provide superior target separation, letting you sneak good targets between iron trash that would mask signals on bigger coils.

You'll want a small coil for:

Old homestead sites littered with square nails and iron debris

Worked-out parks where bottle caps and pull tabs dominate

Between wooden boardwalks or around metal structures

Areas where you need to pinpoint targets precisely before digging

The trade-off is depth and ground coverage. Small coils typically lose 20-30% depth compared to your detector's stock coil, and you'll cover less ground per swing.

Large Coils: Maximum Depth and Coverage

Large coils (10" and up) are your go-to for clean fields, beaches, and anywhere you want maximum depth penetration. They also cover more ground per swing, making them efficient for large open areas.

The Garrett 6" x 11" DD Viper coil hits the sweet spot for the ACE APEX - it's larger than stock for better depth and coverage, but not so big that it becomes unwieldy. This coil adds roughly 15-20% more depth on coin-sized targets compared to the stock 6" x 9".

Large coils work best for:

Beach detecting where targets are typically deeper

Relic hunting in open fields and pastures

Searching for cache-sized targets or large relics

Any site with minimal trash where depth is more important than separation

The downside? Large coils struggle in trashy areas and can be tiring to swing during long sessions. They're also more sensitive to ground mineralization.

Medium Coils: The Versatile Middle Ground

Most detectors ship with medium-sized coils (7" to 9") because they balance depth, coverage, and target separation reasonably well. The ACE APEX's stock 6" x 9" DD coil falls into this category.

Medium coils handle:

General purpose detecting in mixed-trash environments

Park hunting where you'll encounter both clean and trashy areas

Detecting sessions where you're not sure what ground conditions to expect

Beginners who want one coil that does everything adequately

DD vs Concentric Coil Design

Beyond size, coil design affects performance. The ACE APEX uses DD (Double-D) coils exclusively, which provide better ground balancing in mineralized soil and superior target separation compared to concentric coils.

DD coils like the Viper have a blade-like detection pattern that's narrower but deeper than the cone-shaped pattern of concentric coils. This makes them excellent for trashy sites and beach detecting where ground conditions can be challenging.

Coil Selection Strategy

Here's how we approach coil selection based on decades of detecting experience:

Start your hunt with your stock coil. Spend 30-45 minutes assessing the site. If you're finding good targets with minimal trash, consider switching to a larger coil for better depth and coverage.

Switch to a small coil when you encounter heavy iron. If you're hearing lots of low tones and having trouble isolating good targets, a smaller coil will cut through the iron chatter.

Use large coils for systematic grid searches. When you've identified a productive area and want to ensure you've found everything, methodically grid the site with your largest coil.

ACE APEX Coil Compatibility

The ACE APEX accepts all Garrett ACE series coils, giving you several size options. The most popular upgrade is the 6" x 11" DD Viper coil, which provides noticeably better depth while maintaining good target separation.

For extremely trashy sites, consider adding a smaller sniper coil to your kit. For beach detecting or large field searches, a larger DD coil will serve you well.

Real-World Coil Switching Examples

Scenario 1: You're hunting an 1800s farmstead. Start with your stock coil to assess the iron content. If every other signal is a nail or iron fragment, switch to a small coil to work between the trash.

Scenario 2: You're detecting a beach after a storm. Use your largest coil to cover maximum ground and reach targets that may have been buried deeper by sand movement.

Scenario 3: You've found a hot spot in a field that's producing coins. Switch to your largest coil and grid the area methodically to ensure you don't miss any deep targets.

Maintaining Your Search Coils

Different coil sizes require different care approaches. Larger coils are more prone to cable damage from snagging on vegetation. Always use a coil cover to protect the bottom from rocks and debris - a $15 cover can save you from a $200 coil replacement.

When switching coils, let your detector auto-ground balance to the new coil's characteristics. Each coil size may detect slightly differently in your soil conditions.