Testing Detectors should included testing with difference Search Coil sizes and types. There can be a lot of difference in the results. And it ought to include various control adjustments in the test to find out two things:
1.. Does the adjustment setting, or multiple adjustment settings, improve performance in the test to handle the conditions or degrade the performance.
2.. Are the final setting adjustments not just 'functional' for that particular 'test', but are the final settings simple and functional as they are such that the detector can be turned on anywhere and used without a problem?
I have seen people make adjustment setting just to show off a particular test result with their detector, but it wasn't going to be very useful for any serious metal detecting task.
And then we have so many 'tests' that include Iron Nails, but the testing isn't often very practical or really duplicates any in-the-field experiences. Some have a non-ferrous target positioned off the end or head of a Nail swept "down-the-barrel" and others have them so they sweep across the Nail to encounter the desired target.
Both are good 'personal' tests just to give the detector user and idea about detector response-and-recovery, or separation, as well as how the Discriminate setting might affect the audio response as well as recovery or separation in a ferrous / non-ferrous environment.
After a very, very avid 57+ years of detecting, mainly old sites that are littered with Iron Nails and other ferrous debris, I know that far too often we are likely to have our most challenge from sites with an abundance of closely-spaced ferrous junk that can easily mask a non-ferrous target. Also I have fond that seldom is the undesirable target in a nice-and-proper orientation to a desired good target that it served as a good test example.
Back on Labor Day Weekend of '94 I was with a lot of folks from a couple of metal detecting clubs who gathered annually at a Utah ghost town. I was detecting, but also evaluating a newer detectors for a company to see how it handled dense Iron contaminated sites. It didn't do so well for those tasks.
As I walked up a slope to the old "school hill" with the building long gone I could see what almost appeared as a sea of Iron Nails. Everywhere! Close and typically exposed on top of the ground, but knowing that some targets are going to be just under the dirt from relatively shallow to the typical 1" to 4" depth range in most of the ghost towns I hunt. Both good and bad targets.
I wanted to Ground Balance so I looked down just ahead of me to try and find a clean area, but instead, right there in front of my feet, I spied a round disk-shaped target that was surrounded by 4 Iron Nails of different sizes and lengths and it was just a random "as-is" arrangement. A natural encounter.
I also had my notebook with me to keep noted of things I liked or didn't about the detector and coils. The first thing I did was brush a little dust of the coin to see it was an 188? Indian Head Cent. I didn't move or disturb the coin or four Nails. I checked that detector and it didn't do well at all.
I had three 'city' guys come try their White's 4-filter Coin Hunting detectors w/8" and 9½" coils and I used my screwdriver to mark 4 different sweep routes for them to follow. They were not impressed with the result they got since there were no more than 1 or 2 audio hits with a possible of 8, sweeping from the left and from the right on the 4 marked sweep routes.
My "detecting buddy", Debbie, was just down-slope so I called her up to show the fellows how her detector worked. She looked down, saw the coin and nails and said, "Oh, that ..". The she swept fully across the targets and walked a circle around it. Sweep not just the 4 marked routes, but just did a 360° walk and swept back and fort ... and got a good hit on the Indian Head from any direction. Then she looked at the three guys, then looked at me and said "Is that what you wanted?" and I said yes then off she went to find good stuff.
We, Me and Debbie and Donnette her mom, and a few others had talked with the fellows the night before at camp and asked what they were using. We all suggested a different brand detector
(we were all using Tesoro's) and also pick a smaller-size coil
(which we naturally had attached to our detectors).
Since it was a challenging 'test' on a smaller-size coin and multiple Iron Nails, I used some paper from my notebook and laid it over the nails and coin. Got their impressions and traced the exact layout, then picked up the Indian Head an Iron Nails. That evening I used my note paper and the Iron Nails and a firm piece of cardboard and duplicated that exact layout. After I tot back home to Oregon I hired a sign maker to make an exact duplication using some plastic corrugated sign-board material.
I made these up into a 'kit' that I have been selling for almost 28 years now and have provided one of Monte's Nail Board Performance Test 'kits' to White's Garrett, Nokta/Makro, and several dealers. Many many more individuals have also acquired one. Since it is an actual in-the-field encounter 'test' and with the Nail Board solid and weatherproof and the Iron nails are always going to be in the same orientation, it makes a very fair and consistent 'test'
Detector: said:
I did this video nearly 13 years ago. It can perform the same test and that is why these iron nail tests have never impressed me. As long as pretty much any detector is adjusted with iron bias/discrimination close to the iron threshold, any nonferrous metal added will sound off.
I had four DFX's and they were kind of okay, but I have been using, and continued to use, and still have and use the XLT. In many side-by-side comparisons through the years the XLT was the winner (for me) but both are okay, especially for urban Coin Hunting. Not taking on really ugly ferrous contaminated sites.
Detector: said:
In my experience the only true test of a detector is time. Will it remain a top contender or fade away is a matter of time in the hands of users.
Well, the DFX as well as the XLT have "faded away" from the popular use crowd. There are some of us who happen to like them for certain applications and keep them in use, but they have faded from the modern-day popular detectors.
Monte
And for those who are curious, my friend Debbie was using an original Silver Sabre I sold her in May of '86 with a stock 7" Concentric coil. Today she still has and uses it as well as a White's Classic ID w/6½" Concentric coil she added a few years ago. and just this month she bought a Garrett Apex and a NEL 5" DD coil to learn..
I have an Apex, F75+, F19, FORS Relic, XLT and ORX ... but I
always travel with a Tesoro Bandido II µMAX w/6" Concentric coil and it continues to serve me well.
Take a detector to a challenging site and learn it and what the best settings are. Just a natural, as-is environment. Remember that a lot of closely-positioned ferrous debris can easily mask a good target. Here is a short video that proves the point:
https://www.youtube.com/watch?v=kIZYh3mIFq4