Fisher Impulse AQ Metal Detector

Fisher Impulse AQ Metal Detector Overview

The Fisher Impulse AQ Limited is a professional-grade pulse induction detector that First Texas builds for advanced beach, surf and shallow water hunting, and it is made in the USA. It has four search modes, All Metal, Tone, Mute and Volcanic Sand, and its pulse frequency changes with the mode: 4.02 to 4.17 kHz in All Metal, 3.04 to 3.12 kHz in Tone and Mute, and 1.54 to 1.56 kHz in Volcanic Sand. Three manual controls set it up for the beach: pulse delay (adjustable from 7 to 11.5 microseconds), ATS (Fisher's manual recommends starting at 8) and iron reject (the manual warns that the highest settings can eliminate good targets). Audio comes through headphones with low and high tones; the manual has them plug into a keyed connector on the battery pack (the spec sheet lists a 1/4 inch jack). The display is analog. The 12.5 inch mono searchcoil is fully waterproof and the housing is rated to 3 ft (1 m). A rechargeable NiMH 2200 mAh battery gives about 3.5 hours depending on mode. The Impulse AQ weighs 4.2 lb (1.9 kg) and carries a 2-year warranty.

Impulse AQ vs. CZ-21: Which Should You Buy?

The Impulse AQ and the CZ-21 are both Fisher water detectors for experienced hunters, but only one dives. The CZ-21 is a dual-frequency VLF (5 and 15 kHz at the same time) that is submersible to 250 ft (76 m), with a 3-tone target ID, manual ground balance, a no-motion pinpoint and four 9V batteries for up to 55 hours. The Impulse AQ is a pulse induction detector waterproof to 3 ft (1 m), with no target ID or pinpoint mode, manual ATS, delay and iron reject, and a rechargeable battery.

If you hunt the wet sand and wade the surf, especially on black sand or heavily mineralized beaches, and you want to tune a pulse induction detector yourself, the Impulse AQ is the one we recommend. If you dive, or you want tones that sort iron, foil and coins before you dig, choose the CZ-21. The 1280X Aquanaut is the simpler dive-rated option with automatic ground balance.

Impulse AQ, Best For:

• Wet salt sand and the surf zone, wading to 3 ft (1 m)
• Black volcanic sand beaches, using Volcanic Sand mode
• Experienced hunters who want to set pulse delay, ATS and iron reject by hand

CZ-21, Best For:

• Scuba diving to 250 ft
• Hunters who want a 3-tone target ID and a no-motion pinpoint
• Long sessions on four 9V batteries

Impulse AQ Settings That Matter on the Beach

Fisher's manual starts ATS at 8, and we leave it there until we know the beach. Pulse delay is the setting we change most: we run a shorter delay for small, thin gold such as chains and earrings, and lengthen it when the wet salt or black sand makes the threshold unstable. Volcanic Sand mode drops the pulse frequency to about 1.5 kHz for black sand beaches. Use iron reject sparingly: Fisher's manual warns that the highest settings can eliminate good targets, so we keep it low and dig more.

The Batt/Freq position on the mode switch checks the battery and adjusts the frequency; it is not a search mode. With a 3.5 hour NiMH battery, we plan sessions around the low tide and carry the lithium-ion pack for longer days. Rinse the detector and coil in fresh water after every saltwater session.

Where the Impulse AQ Works Best and Its Limits

The Impulse AQ belongs on saltwater beaches: the wet sand, the wash and the surf within its 3 ft (1 m) rating, plus black sand beaches. We use pulse induction where wet salt sand and black sand make a VLF detector noisy. Its limits: it is not a dive detector; it has no target ID or pinpoint mode, so you dig more trash; the stock battery runs about 3.5 hours; and the manual controls take practice. For parks, fields and general land hunting, a multi-frequency detector with target ID is the better tool, and for diving the CZ-21 and 1280X are rated to 250 ft.

Coils and Accessories That Fit the Impulse AQ

The Fisher 8 inch open coil for the Impulse AQ comes with a 27 inch tube assembly and mounting hardware; it is easier to handle in tight or trashy spots than the 12.5 inch stock coil, and the Fisher 8 inch coil cover protects it. The Fisher Impulse AQ 49 Wh lithium-ion battery pack gives 5.5 to 6 hours and weighs 13.3 oz, against about 3.5 hours for the stock NiMH battery. For the surf, the Fisher waterproof headphones for the Impulse AQ are made for this detector. The Fisher tube and hardware for the Impulse AQ is a 30 inch replacement lower tube, worth keeping as a spare on a detector that lives in sand and salt.

Fisher Water Detector Comparison: 1280X Aquanaut, CZ-21 and Impulse AQ

All three Fisher water detectors carry a 2-year warranty and work in salt and fresh water. The 1280X and CZ-21 are VLF detectors rated for diving; the Impulse AQ is a pulse induction detector for wading and surf.

Notes on First Texas's own sources: the 1280X spec sheet and manual give 250 ft, while one line on First Texas's 1280X product page says 200 ft. The CZ-21 spec sheet prints IP54 next to fully submersible to 250 ft, and lists a 10 inch stock coil; the CZ-21 owner's manual lists 8, 10.5 and 5 inch coils. For the Impulse AQ, its product page and the manual's specifications give a 12.5 inch coil, while the spec sheet and the manual's parts list give 12 inch; the spec sheet lists a 1/4 inch headphone jack, while the manual has the headphones plug into a keyed connector on the battery pack. The table follows the manuals.

Why Buy the Fisher Impulse AQ from Serious Detecting?

• Free Shipping on Orders Over $99: Your Fisher Impulse AQ ships at no extra cost across the continental US.
• Authorized Fisher Dealer: Showroom in Ypsilanti, Michigan, full 2-year manufacturer warranty and product registration support.
• Help Before and After You Buy: Our staff answer setup, coil and Impulse AQ questions by phone or email.