Rodog
Jr. Member
OK time to open up this can of worms. Veterans and those in the know Correct me if i am wrong about any of this post. As some of you already know the F.C.C. regulates VLF metal detector transmit power to 100mw (milliwatts). About the same as a cheap childs walkie talkie. Now if all metal detector manufacturers are regulated to this maximum output, the only way to get the extra depth over the competition is to;
1. Have larger coils. Which is bad in trashy areas. And if you have highly mineralized soil a larger coil will see more mineralization which will really test your detectors ability to cancel out the ground. DD coils work better in this situation. Sees less volume of ground.
2. Maximize the coil design for the transmit and receive frequency. For efficiency.
3. Maximize the receive gain circuitry range of operation. This is what most manufacturers do. This is were end users get into trouble with sensitivity adjustments! All must understand that on todays modern VLF metal detectors the sensitivity adjustment is for the receive gain only, not for the detectors transmit power. So with that in mind relax if you have to turn the sensitivity of your detector down for your soil conditions in order to get the stable operation out of your detector for your area of operations. If you have to turn down the sensitivity you will not lose depth. You will only lose hearing the fringe targets because your current setup may be getting too much electromagnetic interference and your detectors ground cancelling abilities may be limited. In other words, if your detector has poor/cheap ground canceling circuitry and can't cancel out the ground very well than your 100mw of transmit power will not punch through the soil to give you the depth that you desire. When it comes to EMI, imagine the how many different radio signals pass through your walls and your body. Police, Fire Department, Local Government, County Govenment, AM radio, FM Radio, Airport Radar, Military Radar, Military Communications, Cellular phone towers and Cell phones,CB and Ham radios, High Tension power wires and well you get the message. Now see what really good shielding can do. This is why the guys and girls out in the rural areas with low mineralization can sometimes turn their sensitivity all the way up and can now hear all the deep targets that the city folks only hope for.
4. Maximize shielding from the control housing to the coil to stop the dreaded electromagnetic interference that plagues the high gain receive circuitry on the high dollar plastic housing models. Hmmm, Faraday shielding in the control housing, Hint Hint. Aluminum shielding spray on the inside of the control housings. Hint, Hint. EM interference goes right through plastic control housings. Plastic keeps the detector light in weight for your convenience.
5. Have true automatic WIDE RANGE ground adjust or filtering that can dismiss the worst soil conditions in the country without sacraficing depth in discrimination.. If it is designed around these parameters then it should work anywhere in the U.S..
So with all of this in mind and seeing that if you take away all of the bells and whistles Like T.I.D., Notch Discrimination, Multi-tones, Bell-Tones, Talking detectors, VLF machines really haven't changed that much.
I guess to me a maximized machine would start out with very efficient coil to transmit and receive frequency design. DD coil of course. With a compliment of Small, medium, and large coils. Maximized shielding from the control housing all the way to the coil stopping EMI in its tracks. And a true automatic wide range ground adjust that will work in the worst soil conditions in the country.
Now for the wants. He He. All metal detectors should be waterproof, and I'm talking about the control and battery housings. Coil covers should come standard on all new machines. I know PROFITS PROFITS PROFITS. VCO pinpointing should be standard on models that have a pinpoint button. Well after all that, now add the convenient bells and whistles and adjust the price accordingly. In other words in a line of VLF detectors from one manufacturer the cheapest turn on and go should get the same depth in the same soil conditions as the top of the line bellsin whistles model with the same size coil.
With all that said are there any electronic engineers and investors out there that would like to build a new detector that the users of this great hobby have been looking to find for a very long time. POST YOUR THOUGHTS, THANKS FOR LOOKING, and HH.
Rodog
1. Have larger coils. Which is bad in trashy areas. And if you have highly mineralized soil a larger coil will see more mineralization which will really test your detectors ability to cancel out the ground. DD coils work better in this situation. Sees less volume of ground.
2. Maximize the coil design for the transmit and receive frequency. For efficiency.
3. Maximize the receive gain circuitry range of operation. This is what most manufacturers do. This is were end users get into trouble with sensitivity adjustments! All must understand that on todays modern VLF metal detectors the sensitivity adjustment is for the receive gain only, not for the detectors transmit power. So with that in mind relax if you have to turn the sensitivity of your detector down for your soil conditions in order to get the stable operation out of your detector for your area of operations. If you have to turn down the sensitivity you will not lose depth. You will only lose hearing the fringe targets because your current setup may be getting too much electromagnetic interference and your detectors ground cancelling abilities may be limited. In other words, if your detector has poor/cheap ground canceling circuitry and can't cancel out the ground very well than your 100mw of transmit power will not punch through the soil to give you the depth that you desire. When it comes to EMI, imagine the how many different radio signals pass through your walls and your body. Police, Fire Department, Local Government, County Govenment, AM radio, FM Radio, Airport Radar, Military Radar, Military Communications, Cellular phone towers and Cell phones,CB and Ham radios, High Tension power wires and well you get the message. Now see what really good shielding can do. This is why the guys and girls out in the rural areas with low mineralization can sometimes turn their sensitivity all the way up and can now hear all the deep targets that the city folks only hope for.
4. Maximize shielding from the control housing to the coil to stop the dreaded electromagnetic interference that plagues the high gain receive circuitry on the high dollar plastic housing models. Hmmm, Faraday shielding in the control housing, Hint Hint. Aluminum shielding spray on the inside of the control housings. Hint, Hint. EM interference goes right through plastic control housings. Plastic keeps the detector light in weight for your convenience.
5. Have true automatic WIDE RANGE ground adjust or filtering that can dismiss the worst soil conditions in the country without sacraficing depth in discrimination.. If it is designed around these parameters then it should work anywhere in the U.S..
So with all of this in mind and seeing that if you take away all of the bells and whistles Like T.I.D., Notch Discrimination, Multi-tones, Bell-Tones, Talking detectors, VLF machines really haven't changed that much.
I guess to me a maximized machine would start out with very efficient coil to transmit and receive frequency design. DD coil of course. With a compliment of Small, medium, and large coils. Maximized shielding from the control housing all the way to the coil stopping EMI in its tracks. And a true automatic wide range ground adjust that will work in the worst soil conditions in the country.
Now for the wants. He He. All metal detectors should be waterproof, and I'm talking about the control and battery housings. Coil covers should come standard on all new machines. I know PROFITS PROFITS PROFITS. VCO pinpointing should be standard on models that have a pinpoint button. Well after all that, now add the convenient bells and whistles and adjust the price accordingly. In other words in a line of VLF detectors from one manufacturer the cheapest turn on and go should get the same depth in the same soil conditions as the top of the line bellsin whistles model with the same size coil.
With all that said are there any electronic engineers and investors out there that would like to build a new detector that the users of this great hobby have been looking to find for a very long time. POST YOUR THOUGHTS, THANKS FOR LOOKING, and HH.
Rodog
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