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TR & TR-Disc. -- Tuning .. related to this initial thread post.

September 26, 2018 05:27AM avatar
I decided to do that quick detector comparison, using the smallest coils I had on-hand for the various models I own, using a rusty iron nail and the copper front-piece of a metal button. The idea was to reject or ignore the iron nail laying on top of the button-front and get a response from the button front from four directions. Both ways lengthwise and both directions crosswise.

Of the detectors and coils I used, as I later described, only 5 models listed passed that sample test by providing 4-out-of-4 hits while ignoring the iron nail. I have had a phone call and a few e-mails asking which of those 5 worked the best and why? A very good question, and to give a worthy answer I need to first explain the Tuning and settings used. To explain what my primary goal was in conducting this detector comparison.

All metal detecting Hobbyists quickly learn that there are some unwanted pieces of junk out there that can be annoying, sometimes producing an audio response that leads us to get down and spend our time recovering worthless pieces of trash. Trash can fall into two categories, Ferrous, or magnetic-based metals, or Non-Ferrous which would be the copper, brass, silver, gold and other favorable metal objects we are usually searching for.

Those two primary worthless objects would probably be a common iron Nail, and in modern-day, high-uses areas, it would be those blasted pry-off Bottle Caps. Most Hobbyists rely on using too much Discrimination to handle the rejection of problem trash, but Avid Detectorist will usually put in the time-and-effort to learn each detector the own and use (because they don't all work the same) and that means learning the best settings, search coil choice, search coil control (sweep speed and coil presentation) as well as Audio Tone ID selection, the usefulness of some visual displays, and most importantly, learn techniques or skills to help 'classify' probable trash.


► What was my goal: To find out which, if any, of my detectors could ignore an iron nail and signal on the button-front with the iron nail laying across the top of it ... and perform as well as most 'conventional' TR detectors. (I am referring to a true TR model and not a TR-Disc. type unit.)


► To achieve this test, Tuning was important: A good working, non-discrimination, 'conventional' TR will be properly tuned with a slight Threshold audio 'hum' and they will ignore most iron nails. By 'ignore' I mean they will not produce a positive response. Instead they might have a slight decrease in the Threshold hum or completely null out and go silent when the coil is swept over a nail.

To try and duplicate this with more modern detectors that rely on a motion-based Discriminating circuitry, you need to know if the detector is a true Threshold-based design or a 'silent-search' design as that can make a difference in audio information. But just referring to this specific side-by-side detector comparison I used one TR and two TR-Disc. models. I grabbed another 'conventional' TR yesterday, a Compass 99B, which has a broader adjustment of the Tuner control. This model represents the early Metal / Mineral Detector design which provides me three different TR / TR-Disc. Tuning options.

I felt I should explain this in order to clarify how I got three of these models to pass the test scenario used. As I described, the 'goal' was to get a good response on the button-front when an iron nail was laid across the top of it and NOT get a positive response from the iron nail. The conventional TR will either just ignore an iron nail (no increase or decrease in audio Threshold), depending upon size and the particular detector used, or it might produce a rejected audio where you hear a decrease from the Threshold hum or even a complete nulling when the audio goes silent.

When a 'conventional' TR mode is used and 'ignores' or nulls on the iron nails and still get a good positive response from the button-front (or other non-ferrous target), that is what made those old TR's useful for hunting in sites that had a lot of iron nails or other small, similar 'wire-iron' to deal with such as bobby pins, cut iron wire, etc.

Way back then, ANY method we could use to deal with typical trash was helpful, and iron nails, bobby pins, and similar types of ferrous debris were the biggest problem when Coin Hunting in the late '60s and early '70s. Now let me get to the topic of 'Tuning' the old TR and TR-Disc. models here in my den.

I have four 1970's era TR or TR-Disc. models.:

• Compass 99B which is a Metal / Mineral (Ferrous to Non-Ferrous) adjustable TR w/standard 8" DD coil.

• Compass Coin Hustler which adjusts from Null to Metal (non-ferrous) range and has a 6" DD coil.

• Garrett Master Hunter TR-Disc. which adjusts from Null to Metal range and a switch to select 'Standard' non-Discrimination or 'Variable Discrimination, w/standard 8" DD coil.

• Garrett Master Hunter TR-Disc. which adjusts from Null to Metal range and a switch to select 'Standard' non-Discrimination or 'Variable Discrimination, w/standard 7¼" Coplanar (kind of like a Concentric) coil.

With both the Compass models and the Garrett Master Hunter, all having Double-D coils, when tuned for a proper slight audio Threshold 'hum' and w/o Discrimination on the Garrett, all three can sweep over the rusty nail, from any direction, and ignore it by nulling out and going silent. That's what used to alert us to nails, bobby pins and similar thin wire-shaped iron.

The Garrett Money Hunter TR, with the 7¼" Coplanar coil, and in the 'Standard' non-Discriminating mode, will NOT ignore the iron nail when tuned with a proper Threshold audio 'hum.' With it I had to de-tune from the Threshold audio towards to Null zone in order to reduce the responsiveness to the iron nail.

Most of the 'conventional' TR models that didn't have a Discriminate circuitry from that late '60s to early '70s era made good detectors for a lot of recreational metal detecting tasks because they handled nails well. Some makes and models using a Discriminating circuit but with a switch to use a more 'standard' or 'traditional' TR search w/o Discrimination did kind of okay, but generally not quite as well. It usually required more operator knowledge and operator control settings to counter the iron nails.

So in the comparison test I did, three of the TR's, which happened to have DD coils, worked well by design and proper tuning. The other TR with the non-DD coil, and the newest of them all and dating to 1976 or so, required some 'off-set tuning' to achieve the successful results. This why, as time progressed and detector models 'advanced' to some degree, I made it a point to keep at least one or two models on hand that handled some of the challenges I faced, so until we got better Discriminating detectors for nail plagued sites, I had at least one simple conventional TR in my detector arsenal.

Monte

PS: I'll get to handling Bottle Caps next which will include learning and using some search techniques.

"Your EYES ... the only 100% accurate form of Discrimination!"

Stinkwater Wells
Trading Post

Metal Detector Evaluations and Product Reviews
'How-To' help for Coin & Jewelry Hunting, Relic Hunting and Useful Techniques.

'Regular-Use Detector Team' are models from: Fisher, Nokta / Makro, Teknetics, Tesoro and White's
'Specialty-Use Detectors' are models from: Compass, Garrett and Teknetics
Pinpointers: Using Nokta / Makro and Uniprobe Pointers.
Headphones: Using Killer B's 'Hornet' and White's Pro Star and Detector Pro's Uniprobe ... All w/'tank style' ear cups.
Recovery Gear: Using White's DigMaster digging tool and Signature Series pouch.
Note: Detectors are listed alphabetically by Brand. Models are chosen as desired based on search site conditions.
Some models are assigned for 'Regular-Use' and others are on-hand for 'Specialty Use.'
Additional search coils, mounted on spare lower-rods, are on-hand in my Accessory Coil Tote.


*** All working well today to make memories for tomorrow. ***

monte@stinkwaterwells.com .. or .. monte@ahrps.org
(503) 481-8147
Subject Author Views Posted

Early morning and this OLD guy just tinkered with OLD and NEW detectors.

Monte 206 September 21, 2018 08:58AM

TR & TR-Disc. -- Tuning .. related to this initial thread post.

Monte 99 September 26, 2018 05:27AM

Next guess, Compass Coin Hustler, Garrett Master Hunter, Nokta CoRe, Nokta Relic and White's MX7...

Hombre 106 September 22, 2018 05:36PM

Randy, you are ooh so close! You got 4 out of 5.

Monte 112 September 22, 2018 06:55PM

Re: Randy, you are ooh so close! You got 4 out of 5.

NWCindy 84 September 25, 2018 02:29PM

NWCindy, you are correct regarding a chance discovery.

Monte 93 September 26, 2018 07:19AM

Do I at least get a consolation prize?.............LOL

Hombre 91 September 22, 2018 08:29PM

A consolation prize? .... Never thouht of that, but here itn is:

Monte 118 September 23, 2018 11:17AM

Re: A consolation prize? .... Never thouht of that, but here itn is:

WM6 74 September 26, 2018 01:40PM

Working on a book, and other ideas. Thanks. N/T

Monte 83 September 26, 2018 05:31PM

That was interesting.

OregonGregg 109 September 24, 2018 07:15AM

Thanks for that history lesson & nice consolation prizethumbs up

Hombre 89 September 23, 2018 02:22PM

Don't be too alarmed, but this reply is brief.eye popping smiley

Monte 99 September 23, 2018 11:57PM

Re: Thanks for that history lesson & nice consolation prizethumbs up

jmaryt 122 September 23, 2018 11:18PM

Hi jmaryt ....lets talk about the 6000 Pro XL later it was named XL Pro

Hombre 89 September 24, 2018 08:44AM

Re: Hi jmaryt ....lets talk about the 6000 Pro XL later it was named XL Pro

jmaryt 86 September 24, 2018 11:43AM

Re: Early morning and this OLD guy just tinkered with OLD and NEW detectors.

Timbertodd 113 September 22, 2018 10:30AM

Re: Early morning and this OLD guy just tinkered with OLD and NEW detectors.

Timbertodd 96 September 22, 2018 06:24PM

Nice guess, Todd, but how many were correct?

Monte 74 September 22, 2018 05:11PM

My Guess

OregonGregg 114 September 22, 2018 06:33AM

Gregg, your 'guess' was correct, but only 1 of the 5.

Monte 108 September 22, 2018 08:12AM

Re: Early morning and this OLD guy just tinkered with OLD and NEW detectors.

jmaryt 96 September 21, 2018 11:48PM

j.t., about the Mojave w/7" Concentric

Monte 115 September 22, 2018 07:54AM

Re: j.t., about the Mojave w/7" Concentric

jmaryt 87 September 22, 2018 05:28PM

My pick for the 5 winnerssmiling smiley

Hombre 114 September 21, 2018 09:38AM

Randy you had two correct out of your five guesses.

Monte 111 September 21, 2018 02:53PM

Okay, I tried these other 4 models. confused smiley

Monte 109 September 21, 2018 04:18PM



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