in identifying your Ground Balance response.
Whimpster said:
I just got a new to me old tone golden uMax..
I hope your unit works okay for you and that your ground is mellow and favorable.
I was a Tesoro Dealer when they came out in Sept. of 2000 and I never found one that worked properly. The supposed four tones were very seldom more than three, and many coins read a tone lower than they were supposed to when searching various ground conditions. You're smart to check all the coils because I used the Tesoro 7" coil 90% of the time back then, and I could switch between 3 or 4 coils and almost always have one or two where my GB was quite negative and caused a lot of falsing.
I soon got rid on all my Golden [size=small]micro[/size]MAX inventory for different models that did work and were more sellable,
for me, after taking a vacation to hunt a variety of ground mineral environments in Oregon Utah, Arizona and Nevada. Never found a place with mellow enough ground for them to work right. There's a reason so many come up for sale all the time and why Tesoro stopped making that one, then all of them, so best of success with your unit. I hope it works for you where you are. It's a [size=small]micro[/size]MAX model I wouldn't own even if I came across one for $25.
Whimpster said:
Today my ground is rock hard and snow filled,so I'm doing some testing.
I thought I would check the golden with a few of my coils to see if the ground balance was positive or negative with a number of coils I have.
A very good idea, and it should be done in both the Threshold-based All Metal mode, and verified in the Discriminate mode should one coil appear to have a negative GB. You don't want it too negative or too positive.
Whimpster said:
Here are the results....
In my back yard found a patch of clean dirt.. in all metal threshold at two 0'clock, sen set at 8.... the original 9x8 coil was negative on the up bobbing.
1.. Did you hear a proper slight audio Threshold 'hum' at the 2 o'clock setting? Sometimes they can vary and describing the knob position doesn't clearly describe the Threshold audio you hear.
2.. The Sensitivity level could have been set at Maximum, or close to where you still had stability to best check the Discriminate mode. The Sensitivity/Gain control on
most Tesoro models is only a function of the Disc. mode. The All Metal mode is designed-in at what they considered 'maximum' Sensitivity and
most models are unaffected by that control so it could be minimum to maximum in the All Metal mode with little or no effect.
3.. You described the positive/negative response based on the audio with the
up-lift of the search coil away from the ground. That is a technique to use when
'Power Balancing' the GB in the silent-search Discriminate mode, but whenever you have a Threshold-based search mode, such as All Metal, it is best to start with the search coil held about 6"-8" above the ground, then
describe the audio response when lowered toward the ground to about ½"-1". A 'spot-on' GB should have little variance when this is done, and a
slightly positive GB might display a
slight increase in the Threshold hum the last ½" to 2".
If you start with the search coil close to or on the ground, hear a Threshold hum, then lift the coil upwards away from the ground, a positive GB will go negative on the uplift, but you have no way to know how positive the GB setting is. You should lower the coil from 6" to determine how soon the audio hum increases to see just how 'positive' the unit is. You could set the GB control, an external knob or internal trimmer, to fully positive GB and with the coil on the ground still have it reduce to a negative response, but such a positive GB on
most Tesoro's will impair depth or eliminate the response to a larger US silver dollar or even a half-dollar in the Discriminate mode.
Again, as I say with most Tesoro models, the Disc. mode has a positive offset from the All Metal mode GB adjustment and usually you will get peak performance in the Discriminate mode with a close to 'spot-on' Disc. mode GB, but that results in a somewhat negative GB in the All Metal mode. I do 95+% of my searching with a Tesoro in the Discriminate mode and prefer to have the GB adjusted for best performance in the Disc. mode.
Whimpster said:
The next coil 5.75 was negative,the next coil 7" was negative,the next coil 8" donut coil perfect,no change or very little, on the up or down bobbing of the coil.
The 3x18 " clean sweep coil was just a tad positive..... 10.5 " coil was positive,and my last coil tested was the 12x10" it was negative...
Again, this should have been done in the All Metal mode listening to the audio change on the
down-stroke, not the up-lift of the coil.
It makes me wonder just how negative the GB was [size=small]
(which you describe as positive)[/size] with the 3X18 Clean Sweep and 10½" coils. If too negative in All Metal you could get falsing in the Discriminate mode. I'd verify performance in the Disc. mode with each coil, checking with the Disc. level adjusted to 'minimum' and bobbing the coil from 6" to about ½" to make sure there was no falsing [size=small]
(an audio beep on the 'up-lift' would alert you to a too negative GB setting)[/size].
Whimpster said:
My question....what coil or coils would give me the best results with this finding?
Not able to determine as the process was not properly efficient.
Whimpster said:
All coils tested were concentric...
No, they were not because the Clean Sweep coil is a 'Wide-Scan' which is Tesoro's way of describing a Double-D design. The round 'donut' 8" is Concentric, and if you're referring to the 10½" white 'donut' coil then it is Concentric. Just be certain your 6" [size=small]
(Tesoro labeled 5.75)[/size] and 7" coils are Concentric and not 'Wide-Scan' or 'Double-D.'
Monte
