Teknetics T2 / A Gain Measurement Chart

The following is a ROUGH measurement of how discrimination levels affect the Gain output on a T2. This was done as a indoors air test. Sweep speed was what I consider a normal speed used when in the field. Not ultra fast as to attempt to attain maximum depth in air testing. Coin response signal accepted for measurement is a two way signal. A fringe questionable one way audio response was not considered as acceptable for measurement purposes.

""Keep In Mind Indoor EMI Affects The Depth/Noise Results. Test Is Only To Show How Discrimination Adjustments on T2 Affect The Gain Output""


Model - Teknetics T2/Software version 6.5 (from 6.0 onwards version numbers make no difference in depth according to First Texas Products)
Coin Used - U.S. Quarter - Cupronickel
Coil - 5" DD
Sensitivity - 60
Tone Selection - 4

Discrimination Levels

0 - 9" depth reading (extremely noisy due to EMI & machines internal circuitry noise)
10 - 7" depth reading (approx 50% less noise than 0 disc setting)
21 - 6 1/2" depth reading (quiet)
30 - 6" depth reading (quiet)
40 - 6" depth reading (quiet)
49 - 5 1/2" depth reading (quiet)
50 - 9" depth reading (this is where another huge increase in Gain occurs, besides the zero setting. Same noise level as 0 disc setting)
60 - 9" depth reading (approx 50% less noise than 50 disc setting)
70 - 8 1/2" depth reading (quiet)
80 - 8" depth reading (quiet)

Observation - the Gain does not seem to follow a straight linear output as disc is increased. Notice that from 0-49 disc there is a 3 1/2" range in detection depth. From 50-80 disc there is a 1" range.

0r

If you remove the disc 0-9 results from above, there is a 1 1/2" depth range between disc 10-49 and a 1" depth range between disc 50-80.

The large gain increase at 50 and the 10-49 disc range has serious implications on how a user sets the discrimination. Below are object disc ranges on T2:

OBJECT / TARGET I.D.

gum wrapper foil / 40-55 (majority of gold rings/jewelry with any detector are found within the foil range and below foil range)
U.S. Nickel / approx 58
alum pull tab / 60-75
alum screwcap / 70-80
U.S. zinc penny / approx 78
U.S. copper penny-clad U.S. dime / approx 83
U.S. clad quarter / 89
U.S. silver dollar / 94




Hopefully, we can get more T2 users to frequent Tom's if more info is made available.

p.s. I think I now hold the record on Tom's for the most edits to a single post



Edited 13 time(s). Last edit at 02/21/2011 01:30PM by TerraDigger.

Nice test Terra. Thx for sharing!

Now THAT is fascinating, Terra. I need to do something similar now with my F70...

Steve

Sounds like I need to try a newer T2.....as mine is very old.

Perhaps First Texas Products would be kind enough to supply you with a current production standard T2 to do testing with. That would be nice

It might happen (T2 SE).

All F75/T2 act the same in regards to the unit acting different at different disc settings. It seems to become more sensitive as the disc is increased which is the exact opposite of traditional detectors. The F75 does it at different numbers due to its scaling.

This has been discussed at length especially when the T2 was first released and then the F75. Some feel the T2/F75 is at a higher gain because it is more sensitive at higher disc settings. Some may need to back down the sensitivity when running a higher disc or turn it up if you run a lower disc. The gain cannot be adjusted on either unit.

A 9” target with disc at 50 and sensitivity at 60 may be equal to disc set at15 sensitivity set at 80

Set the disc to eliminate the targets you want to discriminate out and then adjust your sensitivity---find how the unit works best for you and what you hunt for and go with it.

Mike

See Mal's post on T2 LTD within the "How Combined Gain/Sensitivity/Discrimination settings effect depth" posting.

Hello TerraDigger,

I did look at it initially and just looked at again but didnt follow what I am supposed to see......can you summerize or highlight?

Thanks
Mike

Actually Mike.......at this time I won't. I didn't do the test. And I don't want to 'interpret' another's testing at this point before I have had sufficent time to analyze it.
Just wanted to tidy it up to be decipherable. Perhaps Mal can shed some light on it.