What does kHz mean! what are the best frequencies used for gold ?

[syro]

Hello ,when looking at all the New Gold detectors now being made on the market not one detector has the same KHZ ! and I ask my self do I pay $7,000 for a minelab 5000 or buy one that is new on the market with the same KHZ ! But I cant find any KHZ data on the Minelab 5000 yet other Minelab products have KHz data.

The hertz (symbol Hz) is the unit of frequency in the International System of Units (SI). It is defined as one cycle per second. One of its most common uses is the description of the sine wave, particularly those used in radio and audio applications, such as the frequency of musical tones. The unit is named for Heinrich Rudolf Hertz, who was the first to conclusively prove the existence measures how much is sampled every second (size of the chunks) rather than the number of chunks (frequency).

How Does kHz Relate to the Quality of a Digital Music File?
In theory, the higher the kHz value that is used, the better the sound quality will be due to more data chunks used to describe the analog waveform. This is normally true in the case of digital music which contains a complex mix of frequencies.

However, this theory falls down when you are dealing with other types of analog sound like speech for instance. The popular sampling rate for speech is 8 kHz -way below audio CD quality which is 44.1 kHz. This is because the human voice has a frequency range of approximately 0.3 to 3 kHz. So, with this example in mind a higher kHz doesn't always mean better quality!!

Does the same rule apply in a Gold detector! (The higher the KHZ the Better the gold detector) or is it (The lower the KHZ the better the gold Detector)?

I was looking at the OKM BLACK HAWK with a 600 MHz processor new on the market is this the start of a new Era of detectors! that will blow everything away!

What is MHz?

The megahertz, abbreviated MHz, is a unit of alternating current (AC) or electromagnetic (EM) wave frequency equal to one million hertz (1,000,000 Hz). The megahertz is commonly used to express microprocessor clock speed. The unit is occasionally used in measurements or statements of bandwidth for high-speed digital data, analog and digital video signals, and spread spectrum signals. Other units of frequency are the kilohertz (kHz), equal to 1,000 Hz or 0.001 MHz, and the gigahertz (GHz), equal to 1,000,000,000 Hz or 1,000 MHz.

I have found this new Detector the OKM Black Hawk R3 $5,500 to $7,000

Lightning fast 600 MHz processor

With advanced combined technology of Pulse Induction mono coil and SCMI sensor we have increased depth and metal discrimination. The optional 150 x 150 cm deep search coil allows for detection up to 8 m of buried metal objects and treasures.
Find very small targets like nuggets, coins or jewelry with the optional 16 cm search coil
Advanced programming have made this unit very easy to operate
Search at night with a built in LED lamp and adjustable backlit display
Discrimination of ferrous / nonferrous metals
Wireless stereo headphones for silent metal detection
Various settings to optimize the detector performance to your local soil (Threshold, Delay, Interference, Sensitivity)
External powerful battery pack(Power Pack) for operating times up to 6 hours
Optional 12 V car charger to charge while on the go

 

[shivan]

Check this page out http://electronics.howstuffworks.com/gadgets/other-gadgets/metal-detector2.htm

VLF Technology
Very low frequency (VLF), also known as induction balance, is probably the most popular detector technology in use today. In a VLF metal detector, there are two distinct coils:
Transmitter coil - This is the outer coil loop. Within it is a coil of wire. Electricity is sent along this wire, first in one direction and then in the other, thousands of times each second. The number of times that the current's direction switches each second establishes the frequency of the unit.
Receiver coil - This inner coil loop contains another coil of wire. This wire acts as an antenna to pick up and amplify frequencies coming from target objects in the ground.
The current moving through the transmitter coil creates an electromagnetic field, which is like what happens in an electric motor. The polarity of the magnetic field is perpendicular to the coil of wire. Each time the current changes direction, the polarity of the magnetic field changes. This means that if the coil of wire is parallel to the ground, the magnetic field is constantly pushing down into the ground and then pulling back out of it.
As the magnetic field pulses back and forth into the ground, it interacts with any conductive objects it encounters, causing them to generate weak magnetic fields of their own. The polarity of the object's magnetic field is directly opposite the transmitter coil's magnetic field. If the transmitter coil's field is pulsing downward, the object's field is pulsing upward.

And for the frequencies:

How does a VLF metal detector distinguish between different metals? It relies on a phenomenon known as phase shifting. Phase shift is the difference in timing between the transmitter coil's frequency and the frequency of the target object. This discrepancy can result from a couple of things:
Inductance - An object that conducts electricity easily (is inductive) is slow to react to changes in the current. You can think of inductance as a deep river: Change the amount of water flowing into the river and it takes some time before you see a difference.
Resistance - An object that does not conduct electricity easily (is resistive) is quick to react to changes in the current. Using our water analogy, resistance would be a small, shallow stream: Change the amount of water flowing into the stream and you notice a drop in the water level very quickly.

The minelab PI detectors are slightly different to VLF

PI Technology
A less common form of metal detector is based on pulse induction (PI). Unlike VLF, PI systems may use a single coil as both transmitter and receiver, or they may have two or even three coils working together. This technology sends powerful, short bursts (pulses) of current through a coil of wire. Each pulse generates a brief magnetic field. When the pulse ends, the magnetic field reverses polarity and collapses very suddenly, resulting in a sharp electrical spike. This spike lasts a few microseconds (millionths of a second) and causes another current to run through the coil. This current is called the reflected pulse and is extremely short, lasting only about 30 microseconds. Another pulse is then sent and the process repeats. A typical PI-based metal detector sends about 100 pulses per second, but the number can vary greatly based on the manufacturer and model, ranging from a couple of dozen pulses per second to over a thousand.
If the metal detector is over a metal object, the pulse creates an opposite magnetic field in the object. When the pulse's magnetic field collapses, causing the reflected pulse, the magnetic field of the object makes it take longer for the reflected pulse to completely disappear. This process works something like echoes: If you yell in a room with only a few hard surfaces, you probably hear only a very brief echo, or you may not hear one at all; but if you yell in a room with a lot of hard surfaces, the echo lasts longer. In a PI metal detector, the magnetic fields from target objects add their "echo" to the reflected pulse, making it last a fraction longer than it would without them

 

[GOLD Billyen]

Good question and good reply.

 

[Heatho]

Mate, Khz is actually referring to the the transmit frequency of the coil\detector and has nothing to do with the line out to headphones audio. The higher the freq the smaller gold it will detect, the lower the freq the deeper it will detect on larger targets.

I'm not sure what the audio outputs are running at but I'm assuming the Digital to Analog Converters(DAC) in the GPX5000 would be at least 44.1khz 16bit audio if not 24bit.

 

[syro]

Thank you everyone and yes Heatho I understand "Khz is actually referring to the the transmit frequency of the coil\detector and has nothing to do with the line out to headphones audio." I was Just trying to keep it simple stupid ! you gave me the Answer I wanted.thanks mate.

"The higher the freq the smaller gold it will detect, the lower the freq the deeper it will detect on larger targets."

Great Information to know when buying a new detector to suite what type of prospecting you want to do, now I understand why many people have two detectors.

Kind regards Robert

 

[Heatho]

No worries at all Robert. Yes exactly, even a third detector. I have a 5000 for Gold or deep beach hunting, an Aldi one for the parks and m looking at a third for general beach detecting like an E-track or XP Deus or something similar with excellent discrimination. Something in between the other 2.

Also mate this company you are speaking of sounds a little sus to me, anyone else have any experience with this mob? Long range detectors are mostly very sus tech at best.

Just don't want to see you waste your hard earned.

 

[Guest]

Thank you everyone and yes Heatho I understand "Khz is actually referring to the the transmit frequency of the coil\detector and has nothing to do with the line out to headphones audio." I was Just trying to keep it simple stupid ! you gave me the Answer I wanted.thanks mate.

"The higher the freq the smaller gold it will detect, the lower the freq the deeper it will detect on larger targets."

Yes however this is rendered useless in the goldfields
Because of the highly mineralised soils and ironstone
Stopping vlfs penetrating the ground by interference
Caused by these hence why a pulse Induction such as
a minelab punches deeper.

So either get a gmt or fisher goldbug which are high
frequency for tiny nuggets which besides each other
Don't have any other detector competition Or stick
with a minelab pi.

Its an idea to learn how to sweep the detector in the field
And how fast to swing it and how load your threshold
Should be as all 3 are important.

Eg keep coil flat and parallel to the ground as you swing,
Don't swing too fast so you allow the detector to analyse
The ground properly and make sure your threshold is not
Too high so you can hear the fainter signals.