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Coils are an interesting thing to make, can you build a better one than commercially available? You sure can, my old test coils are on average 20% better across the board. getting good foamed plastic and correct shielding paint is the only difficult part..
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General Discussion / Re: Sdc2300
« on: August 10, 2014, 10:49:52 pm »
Using small coils and having these small gold detectors is like going out and playing bingo, using large coils and going deep is like playing powerball. I really think these small gold detectors will be a 5 minute wonder, maybe these detectors are coming out as the manufacturers may have hit the technology brick wall, these small gold detectors are on par with the vlf detectors available in the 1990's if you want small gold use a gold master, at least you get some discrimination.
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General Discussion / Re: Sdc2300
« on: August 10, 2014, 08:47:04 pm »
To be able to get smaller gold such as what the sdc2300 gets i would be using a very small coil. It is my own personal view that looking for 0.1 gram bits of gold is more of a time wasting exercise as these small bits are worth $1.40 spending 10 minutes trying to find a speck robs you of covering more ground where there is every possibillity of snagging a nice piece. That is my personal opinion.
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New Detector accessories / Re: Interference filter
« on: August 10, 2014, 01:53:38 pm »
The F1A4 i have here also runs quiet, there is a big chip inside the detector that removes impulse noise, i wonder why it was not included into the design of all their newer detectors? I would think that the f1A4 would still be desensitized by any hf signals falling into the passband of the input amplifiers. The input stage is a replica of a SD2100 .
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New Detector accessories / Re: Interference filter
« on: August 09, 2014, 09:09:13 pm »
Hi Mescal,
I tested for any signal loss and I cannot find any loss at all, I tried with a customers GPX5000 in fine gold and the performance was better with the filter in all circumstances, it goes to show that the input opamps are subjected to all types of radio wave derived interference that impact on the detectors performance. Even in quiet areas the depth and sensitivity was better when the filter was installed. These filters cannot be used inside the detector, there are reasons for this, i have seen a filter of sorts in some early detectors and it did not work. I had to get very special materials made to get these to work. The R&D costs have been substantial.
I tested for any signal loss and I cannot find any loss at all, I tried with a customers GPX5000 in fine gold and the performance was better with the filter in all circumstances, it goes to show that the input opamps are subjected to all types of radio wave derived interference that impact on the detectors performance. Even in quiet areas the depth and sensitivity was better when the filter was installed. These filters cannot be used inside the detector, there are reasons for this, i have seen a filter of sorts in some early detectors and it did not work. I had to get very special materials made to get these to work. The R&D costs have been substantial.
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General Discussion / We have a Facebook page
« on: August 09, 2014, 03:16:01 pm »
We have a Facebook page/forum if you want to join, it's a closed group so if you want to post and stay hidden from the public gaze then come and join http://www.facebook.com/groups/bestmetaldetecting There are 2666 members..
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New Detector accessories / Re: Interference filter
« on: August 09, 2014, 02:00:02 pm »
The filter is $180 on Ebay Can do $20 cheaper by escaping the Ebay fee's....come with the correct litz cable interconnect..
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New Detector accessories / Interference filter
« on: August 09, 2014, 07:55:27 am »
I just finished a video on the interference filter i have been developing over the last few months.
https://www.youtube.com/watch?v=oqnhEW7yWUk
https://www.youtube.com/watch?v=oqnhEW7yWUk
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New Detector accessories / Re: New set of upgrades now for SD2000 SD2100 F1A4 series detectors
« on: August 06, 2014, 09:21:20 pm »
We can do the F1A4 the same as we do to the SD GP GPX detectors, they are a good detector...
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Technical / Re: Hot Weather Cold Weather Dry ground Wet Ground Daytime Nightime.
« on: August 06, 2014, 09:18:54 pm »
The article should be out in 2 months time, wet sand could give increased depth as the conductivity is the same, unlike the goldfields that cause pattern distortion and skewing to varying conductance and dielectric constants.
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Technical / Re: F1A4 power plug pin-out query ..
« on: August 06, 2014, 11:56:24 am »
The black box is a multi output switched-mode voltage converter, you need it or the detector will not function.
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Technical / Making the SD2000 SD2100 and SD2200 more quiet.
« on: August 06, 2014, 11:28:37 am »
These detectors are getting on on in years but they all are very good detectors, all can be modded up and detect in most cases as good as the newest detectors that are so very expensive.
The most simple fix is replacing the 150uh inductor in the switching power supply. Over the years the capacitors dry out and lose their electrolyte, this lack of capacitance causes circuit instability
and thus a noisy detector. Replacing the 150 uh inductor in the power supply with a physically larger shielded type with less inductance of 100 uh does a number of things. First is raises the self resonant
switching frequency, this causes less noise as the internal power supply is more smooth in output. The higher the frequency the less ripple and those dried out caps can filter out the noise as the switching transitions
are less in amplitude. Also the detector starts faster, to me this because the existing inductor suffers ferromagnetic collapse at high start up inrush currents. The supply actually runs cooler.
The most simple fix is replacing the 150uh inductor in the switching power supply. Over the years the capacitors dry out and lose their electrolyte, this lack of capacitance causes circuit instability
and thus a noisy detector. Replacing the 150 uh inductor in the power supply with a physically larger shielded type with less inductance of 100 uh does a number of things. First is raises the self resonant
switching frequency, this causes less noise as the internal power supply is more smooth in output. The higher the frequency the less ripple and those dried out caps can filter out the noise as the switching transitions
are less in amplitude. Also the detector starts faster, to me this because the existing inductor suffers ferromagnetic collapse at high start up inrush currents. The supply actually runs cooler.
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Technical / Re: Hot Weather Cold Weather Dry ground Wet Ground Daytime Nightime.
« on: August 04, 2014, 07:18:35 pm »
I just finished a fully in depth article on all the noise sources that upset detecting, Over the horizon radar is the major culprit... the article should be out in a couple of editions.
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General Discussion / Re: WELCOME!
« on: August 04, 2014, 01:04:57 pm »
Hello all, I will be doing a big push to get more member on here, the site still needs some tidying up but I have been very busy developing the next series of mods.