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PimentoUK

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  1. There is a German ( Austrian? ) depth test out there on the web, that does a pretty similar thing. I can't recall if they 'drilled' the hole for the pipe to go in, so as not to disturb the earth. I'll see if I can find it, there may be some tips to pick up from it.
  2. I see you're interested in saving bandwidth. I'm no web expert, but did help Wally find a few issues with Tom D's forum. So a few little things I noticed on your site: On the right side of most pages, there's the 'recent classified', and 'other forum posts' section, all of which have users avatar in miniature. These are actually downloaded as the full-size avatar images, so they total up to a few 100k filesize. Could the avatar simply be replaced by a big black dot, as it is on the left side listing? Related to this, when viewing the Classified page, all the 'recent classified' ads are duplicated on the right, needlessly. And your 'smileys' are massive, 120 pixels wide, some of them, with corresponding filesizes of 15k + . Example the 'oh my' one: The 'like' thumbs-up is 7K: These could all be resized to more appropriate dimensions and hopefully smaller file sizes.
  3. In which case, please ignore all my advice. Those primary Lithium cells put out around 1.8 Volts when fresh, that's where they differ from regular alkaline cells ( and NiMH / NiCad ). It's likely that Fisher didn't design the pointer with those cells in mind, hence the circuit not behaving. As far as Why?, it's hard to tell, no-one has reverse-engineered one. I've heard of a similar issue with the Tek T2 / F75 when run on these cells. The total voltage is over 7 V, ( four AA's ) and the 6 Volt regulator circuit doesn't function, and the resulting supply is unregulated and noisy.
  4. Please be more specific: " Lithium AA " Do you mean those curious KentLi cells, that are 1.5V when discharged, but need a special charger? They are actually a 14500 ( AA ) size lithium cell, with a switched-mode voltage regulator electronic circuit squeezed onto a small circuit-board at the end, which reduces the typical Li cells 3.6-4.2V volts to 1.5V. And can potentially create an amount of electrical interference in the process. Or have you actually used a 3.6V Li cell in place of regular alkaline etc cell ? In which case, good luck, hope you haven't permanently damaged anything with the major over-voltage.
  5. On the 10" GB2 coil, you can also see a small axial-leaded component near to the 'heel' of the inner RX coil. This is most likely a resistor, and it's joined to the single wire loop that runs on it's own between the two main coils. This makes a simple R-L (resistor-inductor ) network, which looks like a target to the coil, likely a very small low-conductivity one. This is there to help get the coil null more precise, there's only so much you can do with moving wires around. Similar effects can be had using small bits of metal, like sheet lead, placed in 'the correct position'.
  6. I've fixed the links in my post, which was hard work. I'm going to have to practice if I'm going to post any more links in the future. The GoldBug2 has a few recognisable features: The fans of 6 or 7 wires are where connection is made to the graphite paint finish on the shell inner surface - one for the top, one for the bottom, I assume. The wires are bare tinned copper, possibly melted into the plastic, possibly taped down. Then the graphite is painted over the top of everything. There's a capacitor in there, the rectangular thing on two wires, typically a wound polypropylene type, in a little plastic box. This will tune the transmit coil. The excess of spare wire is what would be used to get the correct null, where there's very little output from the coil when nothing metallic is nearby. This could be moved around, formed into small loops, etc, in addition to moving the location of the central ( RX and bucking ) coil assembly about a bit.
  7. Quote:"Looks like a ferrite choke inside the GPZ 14" stock coil too but the wires go into it tightly bunched and come out loose. Somethings going on in there" Yes indeed. The TX coil is would from multi-stranded Litz wire, appearing 'fatter' on the images. It's then soldered to short lengths of 'regular' wire ( I don't know what, probably just PVC-insulated equipment wire ) , which are then soldered to the PCB ... or maybe it's the coil cable inner directly soldered to the Litz. The ferret .... well somewhere in ML's patents is the answer. I recall that big blob solder joints were detectable to PI's in some less-than-ideal way. And the ferret 'hides' the joints, somehow. I'll have to trawl Geotech1 to find the details. [ferret's may be known as polecats in your country ] Update: Here ya go ( after 10+ edits, I'm still struggling to get the links to work ... Iwish there was a 'post preview' option ) Patent US20130057286 https://www.geotech1.com/forums Also: MD-Hunter's blog has X-rays of the Nox coil, and a few other types.
  8. That old Whites was picked up for 10 Pounds ( about 13 US Dollars ) at a car boot sale ( like a flea market/garage sale event ). It took a while to work out what was up with it. Several things it turned out, but in the course of refurbishment, I've made it better that new, the residual background hiss is much reduced. This may make it more sensitive, or just nicer to use, I don't know yet. I had some ideas related to tinkering with the audio, which is pretty simple and hence easily changed. And there's lots of space inside that big box for add-on kludges. A curious machine, with the ability to do reverse discrimination, which I understand is for location of black sand areas. Not likely to be much use to me, though.
  9. Hmmm ... shoulda kept quiet about that. It's a short-ish list of what's been done, and a long list of potential projects, none of which I have any time for, currently. It's on a custom shaft. It was originally simply a project because I wanted to do it. So I did the groundwork research, planning, obtained some suitable metalwork, then it all went quiet. Until my original shaft snapped in half, unimpressed by FT's engineering, I have to say. Then it became a more urgent project, which I'm now finally finishing off. There's a self-built cordless headphone link built into it. Though it works OK, I'm not convinced it's perfect ... as a fall-back I have a couple of sets of TurtleBeach cordless gaming 'phones I could hack. The RX gain has been increased, originally to bring the 5" coil alive, though it also benefits non-motion hunting, like hoard-hunting and detecting overgrown wild areas. It has no readily observable effect using the stock coil, except perhaps on dry sand or a freshwater beach?. I was intending to make it switchable stock / hi-gain .... some time. Backlight on/off control is a half-done project. I rarely use/need it, so I permanently disconnected it. But on occasions I wished I could turn it on, so came up with a design, but never finished it. Among the 'projects' are some coil builds. A very large ( approx 18" x 12" bi-axial ) and a two-box conversion. Both really for large-target/hoard-hunting, though the 18x12 would still get coin-sized stuff. I worked out a plan for an all-metal/disc-mode toggle circuit, but that one will probably not happen. With almost no changes, it's possible to run the machine on a single AA Li cell, I was going to do some experiments into the viability of this. It's also been fiddled with for scientific measurement purposes. Raw target and ground signals can be measured internally. A DVM will give useful data, but a data-logger would be better. My first attempts involved a laptop PC sound-card. Fitted with an external chopper circuit, using SpecOszi logger software, and a QuickBasic program to process the data. It wasn't that good, the next attempt will use a recently-purchased external USB sound-card suitably modified, and Audacity software to do the data capture. And I haven't mentioned all the pinpointers and their mods.HeHe.
  10. Thanks for the welcome, guys. I should've mentioned I use a Fisher F75 as my main machine, an F2 as a backup, and as a fun project, a vintage White 2/D hip-mount in need of some love. All my kit is tinkered with, needless to say.
  11. Hi to you all. I'm from the south of England, I mainly detect farmland, woodland, and a bit of park hunting for something different. No prospecting, and I've yet to beach hunt, but one day I must try.... I mainly post on a UK Forum, but sometimes contribute to Dankowski's Forum, as user Pimento. I'm an engineer, who likes the technical aspects of the hobby, so that's where my contributions are likely to be. But it's always good to read what others in the hobby get up to, and Steve seems to have created a nice Forum here. So I'll be checking in regularly, even if my posting is infrequent. Thanks for reading.
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