AT Pro airtesting with various coils

[marcomo]

I posted this over on the NEL forum, thought it would be appropriate here as well.

These are numbers from an AT Pro airtest I did a few months back with a Mercury dime: Full 7 bar sensitivity. Measured to half inch intervals. Measured to what I would consider a potentially diggable audio signal. I have two AT Pros, these are the numbers from the hotter one. The other unit gets about a half inch less depth. I did the airtest in the house and the Tornado gave very slight EMI noise that the other coils did not. I've used the Tornado numerous times in the field and EMI has not been an issue.

NEL Tornado - 11.5"

AT Pro 11" - 10.5"

AT Pro 5X8 - 9"

The Tornado seems well built and because of its bulk does a better job in tall grass than the Garrett coils.

The Tornado is not as good ergonomically as the smaller Garrett coils. Mine does not tighten to the rod as securely as the Garretts.

Separation is what you'd expect - decent for a big coil, but not as good as the smaller Garrett coils.

My NEL connector is inferior to the Garrett connectors, it does not thread on all the way at the control box and I've had it come loose mid-hunt a couple of times.

 

[ajaj]

Thanks for the test and post, but (I know I'll sound like an obnoxious bastard), but I put little credence in air tests. They are one in a hundred data points in evaluating the effectiveness of coils. Your test does, however, confirm my suspicions that the 5x8 is a monster and further confirms that a NEL coil will never be installed on my machine. One advantage to the NEL is the area coverage though, if one is hunting large open fields.

aj

 

[mudpuppy]

Ha! Good one ajaj! I did laugh!

Hey marcomo, your test is still good info for me...I've been thinking about that NEL Attack coil for hunting in the water on my Pro...I noticed those o-rings on the connectors even on the stock Garrett coil are sort of fussy sometimes, a guy has to be real careful not to pinch that o-ring, and get those tiny pins aligned just right and gently push, tighten, push, tighten, wiggle, push, tighten...its not an easy or fast rig to swap coils on at all..frustrating in fact...so I think a guy would want to find what coil works the best and leave it on there! So far I only use my Pro in the beach/water, and am very happy with the results with the stock coil, but thinking maybe more coverage with the Attack?
Mud

 

[marcomo]

aj - You don't sound like one of those at all. I agree that airtests are only accurate for detecting depths if you do your detecting in the air. They give an idea of unimpeded "horsepower", but I've never had a detector get ground depth that can match airtest depth. And some detectors lose more depth in ground compared to airtests than others.

One area where the Tornado really excels is in grass tall enough to render the stock coil much less effective. And in an area that isn't trashy you can go deeper and cover more ground while still having acceptable ergonomics with the 12X13.

Mud, I put a tiny dab of silicone grease on the o rings periodically to keep them lubed. And you are so right, the AT a PITB although with practice I've gotten a lot smoother and faster doing coil changes as long as I put on my cheaters first. I was really glad when Garrett brought out the AT headphone adapter so I could quit dealing with those pins every time I connected the headphones. What would wind up happening is I would just leave the headphones attached after detecting.