northwest f1a4 coil
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Some software and hardware updates now available for the QED.More  QED firmware updates (inc Auto GB  option) just announced here. New  QED hardware updates/options and pictures will be posted  first here  as they become available.

Another satisfied QED user! QED user report for 9 days detecting! User loves it, found it easy to use,found gold with it and he prefers it to his 5000! Also a report on a QED used at the beach for coin shooting.QED users reporting in with their multi ounce gold finds with the QED!
From  another QED user today:"Been out and about today testing and comparing against other machines etc in ground that has been horrible in the past.Bround balancing Ive found very simple and easy.'m using the Nokia booster but need a little more sound/threshold.Otherwise no complaints from me, very impressed."
and :"My QED with the 8” commander on it, out performed my SDC Got bits that don't register on my scales SDC has since been sold"
"My QED is terrific. Lightweight, very sensitive and screams at me when it hits any target. The Detect shaft and the 11" ultra sensing coil is a top quality fitout. I attached an external speaker which added under 200gms of weight in total and still remains very well balanced so i never feel fatigued after many hours of swinging."

Stinky  Pete :http://www.detech-metaldetectorsaustralia.com.au/ is the  Australian distributor for the QED.
This is the only forum where you can talk directly with the designer/ manufacturer of the QED and  also some very experienced QED users.
Jrbeatty and Reg Wilson  and  Yellowfin  (or Doug here for that matter!)have NO vested  or pecuniary interests(or secret deals or cash for comment or any other undisclosed benefits )in the QED other than using it to find gold which it is doing very successfully! The ONLY people deriving  an income from the QED(other than finding good gold) are the approved retailer and Bugwhiskers! The ONLY investor in the QED is Bugwhiskers!
I have never met Jrbeatty or Reg Wilson at Howards house or ANY other location!

australian electronic gold prospecting forum.com  |  DIY forum  |  DIY forum  |  Topic: f1a4 coil 0 Members and 1 Guest are viewing this topic. « previous next »
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authere
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« Reply #40 on: Thursday December 15 2016 18:37:54 AEDT PM »

Hi Alex,

To explain a little more, I drilled and tapped for 4mm metric bolts into my verandah posts and the bolts stuck out horizontally to which I wound the enamelled wire to and then applied the tape to one side first using the guide as I went along, then applied thee other side of the tape to seal it off and like Ian bout 6m was it

I went to all that trouble but could never get the hang of setting up the testing equipment to find out how my coils were(fast)

Cheers Ron
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Alex
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« Reply #41 on: Thursday December 15 2016 19:05:00 AEDT PM »

Thanks Ron Iwas unable to test how fast my last coil was so i just use a 6x6mm aluminium from a beer can and try to compere it with that.I did find the last coil a bit noisy in the gold fields
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Alex
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« Reply #42 on: Monday December 19 2016 22:33:22 AEDT PM »

Hi guys .While learning to construct coils i have noticed how the coil to shield capacidence can  be reduced a lot by increasing the spacer between coil and shield . Could this have a reverse effect on the coil speed by increasing the ground capacidence thanks
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greylourie
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« Reply #43 on: Tuesday December 20 2016 10:46:24 AEDT AM »

I don't know about influencing coil speed. Maybe some more experienced can explain.

But by increasing spacing between bundle and shield, a greater amount of shielding is used - in the case of wrap-around type shielding.. And that would lead to greater coil-shield capacitance and ground to shield capacitance too. So use lower strand count in the shield. I think Ron experienced this when shielding larger coils, and found things worked out by reducing capacitance/shield strand.

I wonder what the spec for shielding is on the new generation of commercial flat wound coils ? Whats the biggest one they make ?
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Alex
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« Reply #44 on: Tuesday December 20 2016 20:29:37 AEDT PM »

Thanks for your reply greylourie .mary xmas
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IBGold
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IBGold at home.


« Reply #45 on: Wednesday December 21 2016 16:44:55 AEDT PM »

The less capacitance the faster the coil shown by the self resonance both methods of shielding have their uses for your coil use bolts with 1.2 mm pitch thread and if it were me I would try for around 10 mm coil bundle to shield spacing.

Regards, Ian. happy face
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Regards, Ian.
authere
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« Reply #46 on: Wednesday December 21 2016 20:45:25 AEDT PM »

Hi All,

When I made Stefan's shielding I made a standard shielding tape and soldered this to the coil and by trial and error by snipping one strand of wire at a time from the shielding, I checked this against depth and noise thru the phones and chose a happy medium

Problem for me was my test bed was nowhere near real life conditions and since I had already glassed the coil..i failed

Cheers Ron
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Alex
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« Reply #47 on: Wednesday December 21 2016 21:45:24 AEDT PM »

Thanks for the help guys .have a mary xmas
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greylourie
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« Reply #48 on: Wednesday December 21 2016 23:25:17 AEDT PM »

  
Hi All,

When I made Stefan's shielding I made a standard shielding tape and soldered this to the coil and by trial and error by snipping one strand of wire at a time from the shielding, I checked this against depth and noise thru the phones and chose a happy medium

Problem for me was my test bed was nowhere near real life conditions and since I had already glassed the coil..i failed

Cheers Ron

Hi Ron,

You could have tried changing the coax to one with different specs. Seems like quite a challenge, building coils.

Regards Jon.
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Alex
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« Reply #49 on: Saturday January 7 2017 17:50:26 AEDT PM »

Hi After reading posts by authere on geotech regarding shieldi minlab coils using Stefarns methord and altering the strand count .Has anyone found a way to get a good strand count using the coil to sheild capacindence and could the coil to shield spacer thickness play a part in altering the strand count
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authere
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« Reply #50 on: Saturday January 7 2017 20:51:28 AEDT PM »

Hi Jon,

Missed this one, I used to make my own coax which used the same wire as in the coil that I was making and then wrapped several rolls(six) of Teflon plumbing tape then spiral wound .15 wire until covered the Teflon, then heatshrink over that....I was told how to go about it by Digger

Alex,

From memory you had to keep the cap below 400 and by adding more shielding space would lower the cap so in some cercumstances you would have to increase the strand count to compensate but the main idea was to overall lower the cap to as low as possible...its all trial and error

Woody was working on this very thing and was using some sought of wire cloth or sheet but I didn't go there

Cheers Ron
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greylourie
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« Reply #51 on: Saturday January 7 2017 23:06:19 AEDT PM »

Hello Alex,

I think Ian gave you optimum guidelines on strands and insulator spacing (a few posts above), for the size of the latest coil you were trying to build. You are asking a lot of questions, and I bet there must be a way to plug figures into a calculator to come up with recommended figures for a given shield type/coil-to-shield spacing/coil bundle thickness.

One important thing you should remember, is these words posted  by Stefan...... "One further point , if you minimize the shield to coil capacitance without making an appropriate reduction in the Q then the coil will be noisy. ie to much coil gain." (   )

It will be interesting to hear detailed info on your success on any of your experiments.


Hello Ron,

Sounds like a good idea to use the continuation of the coil wire as the centre conductor for your coax. I guess you were trying to get rid of solder balls/joints.

But I think it makes for a harder job for a novice to make final fine tune "Q" adjustments to get the coil performing on hard ground. You could sleeve the conductor with varying thicknesses of insulating tube, and vary cable capacitance, but what about impedance/resistance fine adjustment ? Snip wires ? And end up with disconnected 20m long strands sitting inside the bundle ? This is advanced stuff. Most people interested in trying to build their own coils don't have the time,space or facilities to make their own tailored conductor wire.

At least if we use a separate length of coax, we can change it to another type with different capacitance and resistance to gauge differences in coil behaviour and response on hard ground. And save from throwing away a coil as being useless. If solder joints are a concern, then use ferrite beads. I'm just trying to look at this experience through the eyes of someone new to m/l coil construction. The whole experience can be littered with pitfalls.

Regards Jon.
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Alex
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« Reply #52 on: Saturday January 7 2017 23:25:18 AEDT PM »

Thanks Ron.Reading the posts between you and digger .On diggers 3 foot coil he found at wire spacings of 12mm the coil was quite and you found your 6 inch was quite with 20 strands .I thought based on a spoked wheel digger would have about 238 strands ,you may have 1.2 mm spacings on a 6 inch on a 20mm tape .and based on this i was going to try a see if the spacings increased like wheel spokes on a 12 inch coil im about to shield.Also like you i calculate the Q by formula , my first coil was 3.5 and a bit noisy my next 18 inch i dropped Q to 3.3 the same as the military coil it came with so far its an improvement .thanks again
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Alex
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« Reply #53 on: Saturday January 7 2017 23:32:26 AEDT PM »

Thanks Jon. It is a challenge
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authere
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« Reply #54 on: Sunday January 8 2017 00:54:24 AEDT AM »

Hi Guys,

It all became a bit too much for my poor little ole brainbox, I still have a quite a few unfinished coils for the simple reason of not being able to check the finished product. They are all in a box with their shielding wrapped around

I'll stick to finishing off my 5.8m ali boat, just got to finish welding the gunnals and chequer plate deck and a centre console, fit a motor and I'm out there

Cheers,Ron
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greylourie
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« Reply #55 on: Sunday January 8 2017 07:36:12 AEDT AM »

Wow. 5.8 metres. Thats a big one, be plenty room for mates to come along.
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Alex
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« Reply #56 on: Sunday January 8 2017 09:54:27 AEDT AM »

way to go Ron ;fishing surfing all good for brain strain
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