Name: Impulse AQ Limited
Brand: Fisher
SKU: IMPULSE-AQ-NMH
Price: 1999.99 USD
Availability: OutOfStock

Product Description

The Fisher Impulse AQ Limited is a professional-grade metal detector purpose-built for advanced beach, surf, and shallow water hunting. Designed for experienced users seeking deep gold and relics in challenging saltwater or volcanic sand conditions, this machine sets itself apart with specialized Pulse Induction technology and exceptional target separation capabilities.

Engineered to perform where most detectors struggle, the Impulse AQ excels in wet salt environments and black sand. Its adjustable pulse delay (7–11.5 μs) and multitone audio deliver remarkable sensitivity to low-conductivity targets like small gold. Advanced features include iron and ground rejection controls, multiple operating modes (All Metal, Tone, Mute, and Volcanic Sand), and a waterproof 12.5" mono searchcoil for deep detection. The manual settings for ATS, Delay, and Reject offer expert-level tuning for maximizing performance based on your specific hunting ground.

Built to withstand harsh beach environments, the Impulse AQ boasts a durable construction, sealed electronics, and a waterproof housing rated to 3 ft. The adjustable shaft and balanced 4.2 lb frame ensure comfort during long sessions, while its rechargeable NiMH battery delivers up to 3.5 hours of operation. With intuitive controls and a factory-tested waterproof system, it’s ready for serious treasure recovery straight out of the box.

Purpose: Beach Hunting, Shallow Water Treasure Hunting, Gold Jewelry Detection, Wet Sand Searching

Specifications

Manufacturer: First Texas Products, LLC

Brand Name: Fisher Research Labs

Country of Origin: USA

Warranty: 2 Years

Technology: Pulse Induction (PI)

Pulse Frequency (All Metal): 4.02 – 4.17 kHz

Pulse Frequency (Tone/Mute): 3.04 – 3.12 kHz

Pulse Frequency (Volcanic Sand): 1.54 – 1.56 kHz

Operating Modes: 4 (All Metal, Tone, Mute, Volcanic Sand)

Ground Balance: Manual (Adjustable)

Discrimination: Yes (Iron Reject)

Target ID: No

Numeric ID: No

Fe Rejection: Yes (Adjustable)

Fe Readout: No

Fe-Tone Audio: No

Audio: Yes, Multitone Audio Feedback (Low | High)

Volume: Yes, Adjustable with headphones

Sensitivity: Yes, Adjusted via knob

Depth Indicator: No

Pinpoint: No

Memory: No

Backlight: No

Display: Analog

Weatherproof: Waterproof to 1m (3ft)

IP Rating: Not Rated

Stock Searchcoil(s): 12"

Headphone Jack: Yes (1/4")

Weight: 4.2 lbs (1.9 kg)

Battery Type: NiMH 2200 mAh Rechargeable Battery

Battery Life: 3.5 Hours

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Parts & Accessories

Manual

Impulse AQ

Support

For more information and to purchase, visit where to buy , email us , chat with us, or call us at 1-800-685-5050 for any questions.

For repair service in warranty or out of warranty please fill out the RMA form.

Videos

Fisher Research Labs IMPULSE AQ: All Metal Mode Explained

Fisher Research Labs Impulse AQ Assembly

Introducing the Impulse AQ from Fisher Research Labs

Impulse AQ from Fisher Research Labs

Frequently Asked Questions

Is the Fisher Impulse AQ the right detector for my needs?

The Fisher Impulse AQ is specifically designed for serious beach hunters looking for maximum depth and performance in saltwater, wet sand, and mineralized beach conditions. If you primarily detect in parks, relic sites, or highly trashy inland areas, this may not be the ideal unit for you.

Here’s what you get with the Impulse AQ:

Pulse Induction (PI) Technology – Excels in saltwater and black sand, ignoring mineralization that would cripple VLF detectors.
Superior Gold Detection – Optimized for low-conductivity targets like gold jewelry while still detecting high-conductive metals.
Waterproof Construction – Fully submersible up to 3 feet (1 meter) for shallow-water detecting.
12.5” Mono Searchcoil – Provides deep penetration and broad coverage on wet and dry sand.
Adjustable Pulse Delay (7μs - 11.5μs) – Allows tuning for small gold pieces or larger, deeper targets.
Tone, Mute, and Volcanic Sand Modes – Provides flexibility for different beach conditions and target preferences.
Weight: 4.2 lbs – Lightweight for extended hunting sessions.

If you’re serious about treasure hunting in challenging beach environments and want a detector that goes deeper than most, the Impulse AQ is the best tool for the job. However, if you detect mostly on dry land or trashy sites, a VLF detector with target ID and discrimination may be a better choice.

Why is Pulse Induction (PI) superior to Very Low Frequency (VLF) in certain conditions?

Pulse Induction is superior in mineralized conditions, such as saltwater and black sand, because it ignores mineralization while maintaining depth performance. Unlike VLF, which struggles with conductive salt and highly mineralized ground, PI operates by sending powerful pulses that measure time-delayed signal responses. This allows it to detect targets deeper without interference from ground minerals.

How does adjusting the Pulse Delay impact detection of different types of gold targets?

A lower Pulse Delay (around 7μs) increases sensitivity to small and low-conductivity targets like thin gold chains or small earrings. However, it also makes the detector more prone to saltwater interference. Increasing the Pulse Delay (above 10μs) filters out smaller trash and increases detection depth for larger, high-conductivity gold items like thick gold rings, but at the cost of missing very small targets.

How does the Impulse AQ’s iron rejection differ from traditional discrimination methods?

Unlike traditional VLF discrimination, which assigns a numerical Target ID, the Impulse AQ uses a dual-channel system where one channel is optimized for low conductors (gold) and another for high conductors (iron). The Reject and ATS controls fine-tune how ferrous targets are processed, allowing partial rejection while still producing tonal cues to experienced users, rather than a hard rejection.

How does sweeping speed affect detection depth and target response on the Impulse AQ?

The Impulse AQ requires a slow sweep speed for maximum depth. PI detectors process deeper signals over a longer time window, so rapid coil movement can cause the detector to miss deeper targets. A fast sweep also increases the chance of desensitization over highly conductive targets. Keeping a steady, controlled sweep maximizes performance, especially in All Metal Mode.

Why is the Impulse AQ’s ‘Volcanic Sand’ mode necessary for extreme black sand beaches?

Volcanic sand is highly magnetic and can overwhelm most detectors. The Volcanic Sand mode on the Impulse AQ alters the pulse timing to reject extreme levels of mineralization. However, this comes with a reduction in sensitivity to lower-conductive targets (such as small gold items), making it a necessary trade-off for operating in conditions where most detectors would fail.

How does EMI (Electromagnetic Interference) impact the Impulse AQ, and how can it be minimized?

EMI can cause warbling threshold tones, especially in Tone Mode. The Frequency Adjust control allows users to shift pulse frequencies slightly to find a quieter operating range. Holding the searchcoil vertically and rotating 360° can help locate the direction of EMI sources. Reducing Sensitivity and increasing Pulse Delay can also stabilize operation in high-EMI areas.

Why does the Impulse AQ’s battery life vary significantly based on mode selection?

The All Metal Mode consumes the most power due to constant signal processing. Modes like Mute and Volcanic Sand are slightly more efficient as they use additional filtering, reducing power draw. Running at high Sensitivity or using low Pulse Delay settings increases power consumption, while reducing Sensitivity and increasing Delay can slightly extend battery runtime.

What are the audio cues that indicate deep or weakly conductive targets?

Deep targets often produce soft, elongated responses, while shallow targets give sharp, well-defined signals. In All Metal Mode, targets with inconsistent or double-tone responses may be irregular-shaped iron objects. High-tone responses in Tone Mode often indicate low conductors like gold, while weak, erratic sounds could mean a small target near the detection threshold.

Why does saltwater require different detector settings than dry sand, and what’s the best way to optimize performance?

Saltwater is conductive and can cause false signals in low Pulse Delay settings. To compensate:

Start with Pulse Delay at 8 or higher to stabilize the threshold.
Set ATS to 8 to reduce saltwater signal interference.
Adjust Sensitivity downward if false signals persist.
Use Volcanic Sand mode if working in areas with a mix of salt and magnetic black sand.

Is the Fisher Impulse AQ waterproof up to 3 feet for the entire unit, or only up to the battery?

The entire unit is waterproof up to 3 feet, not just the battery compartment.

Can the Impulse AQ withstand heavy rain?

The detector is designed to handle strong rainy conditions. As long as the cables are properly hand-tightened to the connectors, water will not enter the pins or electronics. Additional protection is not necessary.

There have been reports of loose connector plug pins. Has this issue been resolved?

Yes, we were made aware of this issue promptly and took immediate action to resolve it. As a process-oriented company operating under ISO 9001:2015 standards, we quickly implemented a fix to ensure quality and reliability.

Testimonials

What Our Customers Are Saying

'...he found his first coin. A 1946 wheat. I'm glad to say we have a new Digger in the family."

Landon Howlett

Fisher F70

This is a Union Officers belt plate from the Civil War, it was found at a G.A.R. 1895 Civil War reunion encampment...

Jim Doan

Bounty Hunter Quickdraw II

'...great detector please keep me informed on the new machines coming out i got pictures of your detectors for years finding things in fields that have been hunted by everything till the First Texas hit the ground.'

Ryan Vecchio

Bounty Hunter Platinum

"Great contact information, wonderful interaction and the product is wonderful. I will expand my accessories, new usable work products, thanks for this convince and an all USA (EL Paso TX) buy local products."

James K. Sample

Fisher TW6

'...i pulled the trigger on it just in time to detect the new yard my son was on and all i can say is this machine is one serious coin shooter the first yard I scan with it I get my first silver quarter (1946) and my first Morgan dollar (1900) which was 11in .

David Brumfield

Bounty Hunter QuickDraw Pro

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