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Gain and Sensitivity

M

Miser67

New member
I am looking for metal detectors that allow me to independently adjust the GAIN and SENSITIVITY controls on the detector. I thought Gain and Threshold were the same, but I was wrong.

I presently know of two that allow me to that: White's V3i and the older Fisher 5. I know there must be more. Can someone help me kick my brain into gear?
 
xlt, spectrum, & eagle all had those as 2 separate controls.
 
Almost all current offerings by most all manufactures use gain and/or sensitivity interchangeably. There were a few older White's detectors that had both but other than the Vista mentioned above, there are very few with both.
 
:lol: Whaaaat? Maybe someone should go over the definition of these controls first....
 
IDXMonster said:
:lol: Whaaaat? Maybe someone should go over the definition of these controls first....
Click to expand...

Although they would *seem* to be one-&-the-same, yet it is my understanding that this is the difference : Sensitivity is what controls how much strength you're putting into the "send" signal. Gain is what controls how much "receive" signal you are choosing to receive back from the ground.
 
Tom, I always thought it was the other way around. Gain being sent, Sensitivity, how sensitive it is to the returning signal. Don't get me started on White's Signal Balance.
 
I was under the impression that the transmit output was fixed (non-adjustable) on most machines, and that sensitivity determined what the detector would report on based (as Tom S. said) on the strength of the return signal.

Gain is an amplification of the weaker signals?

I've always been a little fuzzy on sensitivity vs gain vs threshold.
 
Ahh, Yes, I'm thinking of Whites "signal balance". And was equating that to the "gain". Ok, I confess, I dunno what the heck I"m talking about, haha
 
I was taught gain is the adjustment of how much of the received signal you let through.
Sensitivity (Adjustable) would be another way of saying the same.
At least that's how it works in 2 way radios. Of course they can label it anyway they want.
 
Gain is the amount of amplification to the receive signal. The transmit signal is usually fixed on most detectors.
Threshold is the signal strength control for audio response. It acts as a signal size filter.
Sensitivity is usually these two functions combined in one control.

That is how I understand it in a simple way.
 
minelabs .....etrac has threshold level, volume gain, volume limit, and sensitivity....each is adjustable to users needs.
 
You guys realize you were posting on a three year old thread? Made me laugh, eventually the mail will arrive……😂
 
It is still a relevant point. I have learned quite a bit about detector behavior under various conditions by experimenting with the SEPERATE gain & threshold controls of the F5 & Vista X.
 
“Sensitivity control” A control labeled “sensitivity”. It actually controls either gain or threshold, or a combination of both, depending on the machine. If both, the higher settings vary threshold and the lower settings vary gain.

“[Audio] threshold control” Determines the signal strength level corresponding to the threshold of audibility. A negative threshold setting is used to suppress signals by a fixed amount so that only signals stronger than that amount will be heard. Negative threshold settings are used to silence internal “circuit noise” and electrical interference. Machines which have no threshold control have an internal threshold which allows silent operation, or a control labeled “sensitivity” which actually controls threshold. …..Some models allow positive threshold settings. In most cases the positive range controls the loudness of a minimum detectable signal, a separate internal threshold determining what will or will not be detected.

“Gain control” This makes signals bigger or smaller. High gain settings make signals bigger, and therefore signals which were originally weaker can more easily exceed the audio threshold, and be heard. If the gain setting is too high, electrical interference or internal circuit noise may cause constant audio chatter. ….Lower gain settings reduce the size of signals, so that relatively weak unwanted signals (electrical interference, deep iron fragments, aluminum foil shreds, etc.) can be silenced.

Source is Dave Johnson, First Texas Products.

HH
Mike
 
Tom_in_CA said:
xlt, spectrum, & eagle all had those as 2 separate controls.
Click to expand...
As Tom stated these do but I'll add a bit more info. There's 3 controls, AC is your discrimination sensitivity, DC is your all metal sensitivity, and the gain. One of the reasons I still swing my XLT from time to time.
 
Fredneck said:
As Tom stated these do but I'll add a bit more info. There's 3 controls, AC is your discrimination sensitivity, DC is your all metal sensitivity, and the gain. One of the reasons I still swing my XLT from time to time.
Click to expand...
Well crap ... 3 year old post. Dang you stoneshirt :rolleyes:
 
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