Question for air testers

[Charlie P. (NY)]

There have been - and commonly are - lots of references to air tests of detectors.

What ground balance setting do you use to be sure the various detectors are on a fair and level [air]field for comparison?

 

[togg77]

My method: GB to the area both like machines and make all settings the same---THIS WILL SHOW THE COMPARATIVE PERFORMANCE BETWEEN THESE 2 MACHINES only.

 

[Coin Rescue Inc]

That is a good question.
My local Ground is between 60-70
The Default Ground Balance is 80 - at 80 I think my air tests are weaker then at GB of 60

 

[Hightone]

I have heard that the best way to air test is to ground balance to the ground, leave the coil laying on the ground, and perform the test above the coil.

 

[Monte]

the local ground mineralization, but it wouldn't be a reality check because the detector is only reading and processing the target signal. The coil and ground are stationary and not in motion.

That's similar to so many dog-and-pony demonstrations I've seen at shows and promotions for a few decades now. A bucket or box with "mineralized dirt" or "mineralized sand" and they GB the detector and set the coil on top of the dirt. Then they have a target on a stick and move it though a PVC pipe that is positioned through the box or bucket and below the center of the coil. The target is moving, but not the coil or ground.

I remember watching a detector dealer at his shop do this demonstration to try and sell some prospecting detectors to a few observing customers. They were surprised at the depth. Also at the dealer's shop and at some trade shows when I would see them showing the amazing depth performance on various coins and buttons.. I only chuckled as I watched the 'new believers' see this demonstration. Then I asked the different demonstrators two questions.: Will the detector do that well in actual hunting?

And once they say Yes, I ask them to put the target-on-a-stick in the center of the test area in the PVC tube, but sweep the search coil over the dirt and material in the container so we can hear the target response. Two vendors tried it, and failed, and didn't know why that happened! Neither did the spectators. A couple of vendors actually knew better and tried to say it wouldn't work due to EMI in the building or whatever bologna they could come up with.

An Ai Test is an Air Test. I like them and I use them, and I make sure the GB is set for a functional setting for the areas I would be searching, but it's only a way to get rough idea of a possible best-case performance in ideal conditions, and fine to check one detector against another for best-case performance. Beyond that it's one way to hear the audio responses, listen to different Tone ID responses, etc. Having the coil resting on the ground is fine, but it is still an Air Test.

Monte

 

[cintitomcat]

Well the F75 camo I just got back after the 2nd upgrade because of am depth. I know air test is just that but should give an indication between disc and am mode. When I ground balance mine then do air test disc bp mode sens-99 I get 15'' on a nickel then switch to am in bp sens-99 I get 11''. Should they be at least close or more in am since they say am is more sensitive?

 

[togg77]

PVT Cook reported that FT told him today that there is NO difference in depth in either 9.0 or 9.1. ?????????????????????????

 

[MarkCZ]

Me and my brother Ron do a lot of air testing, and I've tried different things doing these test over the years. Ground balance is just that "Ground Balance" in the air there is NO GROUND minerals to cancel out! so your not likely to gain or lose a lot if you just use a default setting, or like monte suggested a setting that is common for your area.
With a good number of detectors I've tested I'm getting the idea that with a lot more models than we think the ground balance isn't doing all we think its doing anyway, what I mean by that is YES! its canceling out ground effects but with a lot of units its only doing so when we switch to all-metal mode or pinpoint all metal.
Now, I figure that as we move up line in models then its more likely the ground balance may carry over to the discrimination mode.

The biggest problem I see with air test is how each user judges the target report, which includes what they do to get that max distance on a target.
I have detectors that I can stretch the distance out to unreal distance by doing things like,
Passing the target in front of the coil WAY faster than I hunt! (cheating)
Counting weak chirps or ones that happen every third or forth pass, that's to say responses that if you were hunting you wouldn't call a dig-able signal (cheating)

So, ground balance it the one adjustment that is somewhat out of area usable, while the other settings are the more in use players.

What a person can do is to just set the other settings and while they are set do some test with the ground balance set to different points, now you may find it doesn't do much in the discrimination mode if anything at all, but if you test in AM then it may make some differences. I NEVER hunt in all metal mode but I do use the AM pinpoint mode A LOT!

Mark