Fisher Impulse AQ Ltd Preliminary Report

[Steve Herschbach]

Short answer, the Impulse AQ is the real deal. Advice to Tom Walsh - put all resources necessary into getting the full retail version approved for sale ASAP.

I will not be hunting saltwater with the Impulse in the near future but instead local freshwater lakes. The coast is farther than I want to drive for now.  Lake Tahoe is a freshwater lake, with beaches made up from material derived from granitic rock. It is a very large lake, with 72 miles of shoreline. Most beaches are pebble beaches. Sand Harbor is a one of the rare sandy beaches on the lake. The sand is heavily laced with magnetite that will greatly inhibit or overload and shut down most VLF detectors. Metamorphic and volcanic hot rocks are also fairly common on the lake. https://www.earthmagazine.org/article/travels-geology-lake-tahoe-jewel-sierra-nevada

Black sand (magnetite) layers exposed on beach

Closeup of magnetite black sand. Note dark gun metal granular nature of the sand. Highly magnetic.

This is a magnet that has been dropped onto the sand and picked back up - a golf ball size lump of magnetite.

Most of the soils in my area have a high magnetic component, and most VLF detectors get roughly 60% of the depth normally quoted on most U.S. forums. A ten inch dime here is a bit of a joke... more like 5-6 inches. This beach is particularly bad, and will send the Equinox into almost continuous Beach overload mode. Other modes have to have sensitivity drastically reduced or the machine basically shuts down.

Despite this beach having thick magnetite concentrations I had no problem running the machine at 7 uS pulse delay, full sensitivity. I used the default marked settings for other controls. The detector is extremely stable, with rock solid audio.

This machine will have me digging as deep as I care to dig. I've almost bit on a TDI Beachhunter a couple times in the last year, and am glad now I did not. This is the detector White's could have made if they had not basically stopped trying to advance the TDI in a meaningful way.

There is only one thing about this machine I did not like to the point of needing to do something about it. At 5' 11" the two piece rod is too short for my liking, like by a couple inches. I had to keep the coil a foot ahead of my feet and was still bent over. Thankfully I just found that the middle section out of a standard Fisher three piece rod (I have one in my pile of stuff) plugs nicely into the gap, and will give me that extra reach I need.

The power cable sticking out of the back makes it difficult to find a way to prop the detector against my side or hip without stressing the cable while digging. I need to rig a bungee so I can just let it hang by my side while digging.

The coil is not as heavy as it looks, and swings quite nicely above the water. Swinging the 12.5" coil underwater however  is a bit like swinging through molasses. I'm fine with it but may be a bit much for some, especially in running water. The coil is just ever so slightly buoyant. Not so much as you notice it while swinging - it feels neutral. But if released sitting in the water the coil slowly floats to the surface. It would take only a very small amount of counterweight to make it negative instead of positive buoyant. The coil has no scuff cover, just an exposed epoxy bottom. No word yet on when scuff covers will be available.

I like the headphones, very familiar feel to many I've used gold nugget detecting. Snug fit, maybe too snug for some people but good for my not huge head. Good sound exclusion, and plenty of volume for above water use. As in I was running volume 3-4, but I do keep volume low to protect my hearing. How well they work underwater I am unsure but I suspect as well or better than most competitors. The cable has plenty of length, but is not particularly robust looking, and I will probably tie it off on the armrest or someplace to keep from stressing the cable too much near the plug.

This detectors Achilles Heel should not surprise PI users - wire and bottle caps. Forget videos seeing rings while rejecting nails... not a ton of nails on most beaches. Show me a video of a ring buried in sand surrounded by hair pins and wire tie wraps plus a few bottle caps. Yup, it's still a PI.

That said, anyone who is a PI hunter and likes PI detecting... I think you will like this detector. I'm thrilled with it. Tons of stable power. It will probably need to be dialed back on pulse delay or sensitivity or both in salt water, but once set just under whatever salt threshold is required this machine will deliver the goods.

The audio is great. I easily found myself able to start cherry picking deeper "round" signals. The reject setting is most effective as a way to not waste time on dimes or quarters and some large ferrous. The wire and hairpins tend to be shallow and sharp, the deep targets easily discerned with a more centered, marginally softer signal. The coil has the classic double blip on shallow targets as they pass under each edge.

This edge coil sensitivity is extremely important. Not only does it quickly identify small surface targets, but it is a great aid in pinpointing. Get the target out of the hole and turn he coil on edge, and quickly locate the item in a pile of sand. Those surface targets are also quickly isolated for a quick scoop and recovery.

Fisher Impulse AQ Limited controls

The default reject breaks at shiny clean copper coated zinc pennies. They and dimes, quarters, and I assume copper pennies read low tone. Nickels and corroded zinc pennies (ate through the copper) read high tone good, as they should. So the default break is between new clean zinc pennies (low tone) and corroded zinc pennies (high tone). Side note: digging low tones in a park for coins may be fun to try.

The Reject control surprisingly seems to have less impact on disc results than the ATS control. ATS at zero basically means no disc no matter where the reject setting is. At the default reject setting of 6 corroded zinc reads good, and advancing the control to max changes nothing. But advancing the ATS control from default 8 to 8.5 flips the corroded zinc to a low tone. And also my gold wedding ring. I left the ATS and Reject at defaults (see photo) as they seemed best... as they should be.

The Tone setting does not appear to cost much depth - the 10% quoted by Alexandre seems to be in the ballpark. You can hunt all metal and use a couple tricks. First, you can switch to Tone to check for the coins listed above or large ferrous. Second, if you are dealing with foil, the Pulse Delay control rotates continuously, so you can switch right from 7 uS to 11.5 uS. Foils drops out a lot more than rings, but so will small gold items. Still, a handy thing if you are looking for rings. But I thought running in Tone mode directly was a pretty fine way to go for what I was doing. The machine does not lack for depth even when you give a little up.

The Fisher Impulse AQ is made to find rings. I actually am very impressed with the small item capability on dry sand or in freshwater... it will hit tiny stuff just fine and I think finding gold nuggets will not be too much of a challenge with the AQ. But it is really made as a ring finder. I am certain I can cherry pick ring signals with this machine. I found no rings, but dug nickels and corroded zinc at depth and with audio that was easy to discern to my admittedly trained PI ear. I messed with quite a few shallow targets just to confirm most were wire and hairpins. Usually a sharp signal under each edge of the coil.

Well, folks, as I suspected it is not a magic wand. However, this PI guy is extremely pleased with this detector. Basically I just have to extend the rod, rig a bungee so I can drop the detector without it hitting the ground, and I'm good to go. I actually like hunting in tones... it adds more audio tells and I really do not mind passing on a lot of coins. I'll worry about maximizing depth later when I run out of beaches and targets. Mainly I need to get my eyes healed up to where I can really deal with water more effectively. Right now shallow wading and cherry picking will suit me just fine.

That's most of it. I'm not going to take time to do any proving of anything. Those of you who know me or who have followed my posts for a couple decades know I'm not a BSer. There is not one review I have done in the last twenty-five years I think was off base or that I would change, and they are all still out there to prove it. If you are a serious PI hunter you are probably going to want one of these, though most people are going to want the improved battery/deeper depth rating version. I'm sure I'll be in line for one of the first when they are available. All you folks who have never used a PI and expecting a PI with VLF type discrimination? Well no, this is a PI and it is just a whole different ballgame. You get these things for depth, and most especially depth in difficult conditions where VLFs lose a lot of depth.

“Deeper“ is a one dimensional way of looking at metal detecting. My goal is to be more efficient and to locate more “good” targets per hour of metal detecting. The Fisher Impulse AQ offers great ergonomics, superb audio, an advanced discrimination system (for a PI), allowing focus on ring type targets, and as much power as the hunting environment will allow. It’s not just “more depth”, though the AQ has as much as is possible, but the total package that matters to me. When it comes to the total package, including depth, the Impulse AQ delivers. 👍🏼 All Fisher needs to do now is get the full retail version, with improved batteries and depth rating, on the market so people anywhere can buy one. I hope that happens by the end of the year.

Sand Harbor by noon - social distancing at its finest!

[matt]

Thanks for the report and hope you can get some rest for your appointment tomorrow. From the looks of the beach, you might have to hunt really early or late to get some ground!

[Steve Herschbach]

I was there at 8 am opening. After an hour the beach was getting so busy I got in the water and hunted just off the beach. Water is cold still so only a few tough souls out in it, easy to work around. By noon the wind kicked up enough the waves were getting hard to see through and work in so I called it a day. They are running the parks at 50% capacity. The guy said on weekends they are “full” and closed to newcomers an hour after opening.

First Texas Middle Rod section, current on many Fisher, BH, and Teknetics models. Will the rod too long for many people at the shortest settings so not a magic fix. This plus shortening the lower rod would be the best compromise,  but I am sure FT was looking more for stability and integrity with the two piece rod design.

Speaking of rods - we need a part number and price for replacement lower rods with yoke soon. You just know they are going to get broken, and the unique design means no easy fixes.

 

[abenson]

Thanks for the report Steve. Sounds like the AQ limited is right up my alley. Now if I can just get my hands on one.

[Joe Beechnut OBN]

Great return on the time at the beach! Good Luck on your appointment tomorrow!

[Tmox]

Freaking Awesome reporting, music to my ears.
Godspeed to you tomorrow.

Tim

 

 

[okara gold]

Nicely detailed report Steve. A lot of good information for your first time out. Good luck with the eye today!

[Skull diver]

This is exactly what I was expecting from it.

Due to the tough saltwater training with the Tdi Bh , I'm just waiting for this beauty to finally hear signals more than noise.

I'd love to see soon an 8" coil too.

Many thanks for your report!

Really detailed for a first shot!

[schoolofhardNox]

Thanks Steve for taking the time to post your first impressions. I'm glad it has solid performance even maxed out. Were you in a location that had any noticeable EMI when you used your other machines previously there? How did it handle the EMI? Also how does it compare with the GPX? Sounds like it would be smoother and a bit deeper than the GPX.

[GB_Amateur]

Nice, no nonesense ("call 'em as I see 'em") review, Steve.  I'm not trying to add more work to your plate as I know you are motivated to give this new detector the best workout you can.  Just wondering, since you've made mentions of parallels between this detector and the White's TDI, will you be trying it out for coin hunting as you detailed years ago for the TDI?  Do you expect better, worse, or about the same performance in that capacity?  7 microsecond minimum (compared to 10 microsecond) delay is one big difference but I suspect that won't add any coins (well, maybe our tiny nickel 3 cent piece...?).  Still, will there be better discrimination against rusty, bent nails?  And there's always almost everyone favorite wish -- deeper.

Hope your cataract surgery #2 goes smoothly and you're back swinging soon (with renewed ability of a 15 year old to spot those sun-bakers 😏).