Getting ready to build the MPP

[KRinAZ]

The voltage swing of +/-5V mentioned in the Build Document is only a guide. The TL071 rails out at about 4V, so your voltages are fine.

Oh, ok, good then!

[KRinAZ]

You can buy a stick for $48 (ouch) http://www.ebay.com/itm/271609965612...%3AMEBIDX%3AIT

And Coil Housing for $14 http://www.ebay.com/itm/121469795547...%3AMEBIDX%3AIT

And a box for $15 http://www.ebay.com/itm/OtterBox-Pur...item19f156f030

Or look for a cheapo detector. I got a tracker IV for $60 brand new planning on using the stick for other MD's

OK, cool, I especially like the Otterbox! - the only reason my ancient iPhone is still alive is because the Otterbox protected the landings of it's maybe 30 drops/falls, so I would really like an Otterbox waterproof housing for the electronics. I know the total solution would not necessarily be waterproof - but the electronics would be well protected!

[KRinAZ]

Try this -> http://www.whiteselectronics.com/space-saver-rod-kit

Wow, I didn't know the whole pole assy could be bought at White's as a kit - very cool! & price seems fine to me - that's what I want!

[KRinAZ]

You could use an ice scraper as a stick;
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Haha, good idea actually - would need to find ones that were all plastic...mine is sturdy but metal...

[KRinAZ]

I bought some GMT housings. They were about $25 each;
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That's a really good idea - eBay also?

[KRinAZ]

I got a tracker IV for $60 brand new planning on using the stick for other MD's

Sven did BH in GMT housing. http://compass-metal-detector-forum....td7600844.html
nice done...

Cool, very nice solution, I'm now on the watch for empty GMT housings...I actually own a GMT but IMHO it's right there in the very short list of the best of the VLF gold hunters - I get a target response from a .3 grain (not gram) tiny gold speck at 1 inch (about 25mm) - it's one of my test targets - and wouldn't dream of robbing anything from it...

[SVEN1]

Try this -> http://www.whiteselectronics.com/space-saver-rod-kit

That's what I use with my PI's.
Take note, White's uses an old picture. You no longer get the all-metal arm cuff as pictured. For the past two years the arm cup you receive is the plastic one used on the Prism detectors with the stand up feet.
If you want the metal arm cuff, its an extra $10US. If you rear mount a box, the feet get in the way, so I opt for the metal cuff.


Also, the Gold Mountain control boxes can be purchased from Keith Wills, he will not ship outside the USA.
Think he had about 200 of them along with matching s-handles etc.
http://www.brokendetector.com/

[KRinAZ]

That's what I use with my PI's.
Take note, White's uses an old picture. You no longer get the all-metal arm cuff as pictured. For the past two years the arm cup you receive is the plastic one used on the Prism detectors with the stand up feet.
If you want the metal arm cuff, its an extra $10US. If you rear mount a box, the feet get in the way, so I opt for the metal cuff.


Also, the Gold Mountain control boxes can be purchased from Keith Wills, he will not ship outside the USA.
Think he had about 200 of them along with matching s-handles etc.
http://www.brokendetector.com/

Very good to know SVEN1, I will want the metal arm cuff - I agree - it's all around better. Thx for the link to that site also.

I'm in the process of a difficult move, so it may be a bit before I order any stuff and get back to the MPP project. I really want to get the MPP field functional and experiment with the basket weave coils some more, as well as experiment with some mods to the MPP.

I'm going to be camping on a gold claim soon that I have access to, an area where fine gold to 7 gram little nuggets are supposed to be present, will have my GMT and Classic ID with me, really wish I had the MPP also...

[Davor]

You could use an ice scraper as a stick;
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I'm lurking for some time to get some on a discount

[6666]

Hi KRinAZ, from post #77 "I've discussed this coil with Don Bowers and suggested that if a number of us build these coils and would like a housing he could make housings for us. Currently it looks like the housing would be about 8.25" x 10.25" x 1", could be any mount we all agree on (he usually uses the 19mm Whites/Tesoro/Minelab mount tabs unless otherwise specified) We will need to get the cost per housing from him when we are ready, it appears they would be around $15 each (US Dollars) "

Count me in for two housings; I would prefer the Minelab 24mm spacing on the mount tabs. The wider base is stronger and is the standard for most Pulse Induction after market coils except for Whites. Spacers/washers can be used to fit with the 19mm shafts. He may be able to make both widths by having interchangeable tabs on his mold form. The inside height should be a minimum of 1".

Did anything come from this ?

[Chet]

I think KRinAZ is off digging gold so I just ordered to round Clam Shell coil housings from Don Bowers. He is increasing the inside height to accommodate the fatter winding of the Basket Weave coil.
Chet

[6666]

Thanks Chet

[baum7154]

Hi KRinAZ, when I built mine I didn't even think to check the DC voltages on TP3. The scope is the way to go on most checks. Looks like you are well on the way to completing yours. The coils are very sensitive to any metal in the work area. Two solutions for this. Suspend the coil by cord from the ceiling away from the bench, or place it on a plastic wastebasket on the floor away from the bench.

I measured a 4' length of twisted # 22 Teflon wires with thinner insulation than yours. It measured 39pf on the capacitance meter.

Great job on the new coil. Looks like for others using your template that it should be a little greater in width and the slots should be a little deeper. This would help on the inside turns to keep them anchored better. I had a problem with this and it looked like baum7154 had a similar problem with his coil.

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Just came across this thread and have enjoyed reading your progress in making your CHance PI basket coils. As you mention above I did run into slot depth issues and this is partly because I intentionally wound more turns on the oval coil in order to do close comparison tests against my 335uh round coil. Once the tests are completed I will reduce turns to have a 300uh coil and test results. Especially on the oval coil my inner slots will be .450 to .500" deep only on the rounded ends. These mono coils are the best I know of and are the only ones I now build after three years of optimizing them. The self resonant frequency of my 335uh coils with twisted pair feeds are in excess of 1 MHz and they are critically damped at 1000 to 1100 ohms.
Good luck with your builds!
Regards,

Dan

[6666]

Dan have you ever tried your coils on wet beach sand ?

[baum7154]

Not on salt water beach but have used them on wet mineralized stream side sand and at 8us sampling delay. They behave pretty well but at that short delay I get lots of small aluminum bits as targets.

Dan