General tuning question

[gallileo60]

Ok so im a Ham Radio operator, and one of the things about radios are after a while they need an alignment, the if section, etc....Some new radios are poorly tuned from the factory..This is especially true of Cheap CB Radios..It is amazing what a "good" individual tune (versus an assembly line tune) can do for a radio...Is this the case with detectors??

 

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[DDancer]

Not that I'm aware of gallileo. Unless the detector is a pretty old model most modern detectors are pretty much locked up component wise and don't require tuning~ though some makes can be adjusted by their manufactures usually to "tune" for different coil sizes dependent on output frequency. I've not found anything posted that would suggest otherwise. Maybe old BFO detectors would benefit from some tweeking~

To my knowledge detectors don't use intermediate frequencies or require heterodyning. But then most manufactures don't publish their specs or schematics. If you do decide to tweek a detector I'd be interested to know how it goes.

 

[roaddust66]

I am an inactive ham. Been licensed 30 years. I know what you are saying. You are referring to " peaking a radio out" ...with a meter and a diddle stick. There is some of that going on but I believe it is not general knowledge among detectorist. I have heard Tesoro Company will " peak out " one of their machines that have automatic ground balance in accordance to the region of the country you live in. I hear they have a chart with regions of ground mineralization and adjust accordingly.
At the same time...a good amateur radio operator knows it is the antenna that counts. Not the amount of power you are running. I can talk to anybody in the world on a hundred watts with a high performance antenna. Right ? So the same would apply to using a more high performance coil. Right ? I will admit I have wondered if changing the battery voltage slightly Maybe increasing it by two volts and checking the power. Would it make a difference ? Buy a larger coil and forget about that diddle stick !!

 

[DDancer]

Some machines may be helped with higher input voltages. On the old minelab SD series PI's increasing the input power to 14 volts hotted up the machine's. I did so for my SD2100e and saw lots of mods for the old 2000's that did the same. It also had a tendency to make the detectors slightly unstable at times.
Never seen anyone hot up a VLF. As to tuning for the antenna well that's just good common sense to anyone who understands and uses radios.

 

[OBN]

Never seen anyone hot up a VLF

Minelab Excalibur (VLF / Multi Frequency), took what the detector offers as a stock machine and enhanced performance thru modifications.


1. Being able to change coils on a water machine is great advantage, I can go from a 5 inch Sunray to a 13 ULT

2. A great weakness to all water machines, the headphones. Instead of Piezo Buzzers...These are speakered IP68 headphones, Same speakers as the Sunray Pro Golds, Black Widows, etc. Perfect for the faints, and with the Peltor 105s 3o db rating ..along with the Gel Pads You hear targets no one else can...

3. Just like a land hunter being able to swap headphones to ones for PP hunting only, much louder because I run Doc's Treasure AMP, just like the GPX series I can separate the Volume of the target from the threshold. Bringing up the faintest of faints in All Metal/PP. Deep targets that were once covered by the threshold are now uncovered by Lowering the threshold even more.

4. Being able to run full sensitivity in PP/AM one can achieve greater depths, having this control at your finger tips for a fast toggle over to Discriminate then back...toggling to discriminate to Tone ID the target before it has a chance to false, then back.



5. Running a Hotter Battery from the stock battery voltage of 14.4 at max, Compared to 16.9 Max with the LIPO



6. And Finally direct wiring of the coil to the components on the PCB



Has all this made a difference? Gold sure has increased a lot but also I have been doing more time and learning the machine better, along with the beach.

 

[DDancer]

I stand corrected Thanks OBN. Strange~ minelab again. hehh.

 

[Carl-NC]

Ok so im a Ham Radio operator, and one of the things about radios are after a while they need an alignment, the if section, etc....Some new radios are poorly tuned from the factory..This is especially true of Cheap CB Radios..It is amazing what a "good" individual tune (versus an assembly line tune) can do for a radio...Is this the case with detectors??

Detectors use synchronous demodulators, what you would call "zero-IF" in radio-land. It is impossible for them to get out of tune. However, the ground balance/tracking and the discrimination relies on a phase reference that is calibrated at the factory, and that can get out of whack.

I have heard Tesoro Company will " peak out " one of their machines that have automatic ground balance in accordance to the region of the country you live in. I hear they have a chart with regions of ground mineralization and adjust accordingly.

I think you mean preset GB, as automatic GB is... automatic. In any case, I doubt it. Ground doesn't vary by regions, it varies by miles, and sometimes by feet. You can't say, "That guy lives in Ohio so we'll set it here."

Also, metal detectors don't use an antenna, they use a transformer. Apples & bananas.

 

[gallileo60]

I am an inactive ham. Been licensed 30 years. I know what you are saying. You are referring to " peaking a radio out" ...with a meter and a diddle stick. There is some of that going on but I believe it is not general knowledge among detectorist. I have heard Tesoro Company will " peak out " one of their machines that have automatic ground balance in accordance to the region of the country you live in. I hear they have a chart with regions of ground mineralization and adjust accordingly.
At the same time...a good amateur radio operator knows it is the antenna that counts. Not the amount of power you are running. I can talk to anybody in the world on a hundred watts with a high performance antenna. Right ? So the same would apply to using a more high performance coil. Right ? I will admit I have wondered if changing the battery voltage slightly Maybe increasing it by two volts and checking the power. Would it make a difference ? Buy a larger coil and forget about that diddle stick !!

Thanks for all the replies....Well not really peaking, to do a true tune you need a Signal Generator, an Oscilloscope, and a few other pieces of test equipment..Also you need to know all of the Factory Test points in the piece of equipment being tuned...In the old days Caps, and Resistors would change values over the years, and tuning would somewhat restore the Radio to Factory Specs...Plus in a lot of "Assembly line" Radios they were tuned in a hurry, and were not right to begin with..I have had several Shortwave receivers that benefited greatly from being tuned to factory specs....Just was not sure if MD's fell into this category, as they are more, or less transmitter, receiver units....

 

[U.K. Brian]

You have to ask why all new detectors and coils don't match those of the same model/version. Because they don't. Hot, warm or cold is a matter of luck unless you have a sympathetic dealer who will allow you to try out a few detectors of the same model before buying, pick the best, then swap the coils round to make certain thats the best of the bunch.

 

[gallileo60]

I was kinda wondering about the coil match also....