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DIY forum => DIY forum => Topic started by: Alex on Sunday June 5 2016 12:31:22 AEST PM



Title: f1a4 coil
Post by: Alex on Sunday June 5 2016 12:31:22 AEST PM
Hi all have wound my first coil for  a minelab f1a4  wound similar to IB gold and Stephans method. same self wound litz and used polyporylene pallet straping for a spacer between 5 turns  11 inch with i think 23 turns  results are  305uh 1.139mhz .4 ohms. I have enough cable to continue straight to the control box . Is this a good idea should  the lead be sheilded or would i be better of with a coax cable


Title: Re: f1a4 coil
Post by: IBGold on Sunday June 5 2016 17:27:31 AEST PM
Hi I have been using the coil bundle start wire as the centre conductor and making my own coax using a combination of heat shrink and spiral wrap as the coax insulator then using the coil end wire as the shield spiral winding the separated strands it as the shield wire with a couple of extra strands to connect to the coil shield then cover the lot with heat shrink the more gap you can get between the centre conductor and shielding the lower the capacitance will be and the faster the coil will end up this also applies to the coil shielding.

Regards, Ian. ::62::


Title: Re: f1a4 coil
Post by: Alex on Sunday June 5 2016 18:18:00 AEST PM
Thanks Ian dos it make much difference whether the start coil wire or the end one is used in the centre conductor


Title: Re: f1a4 coil
Post by: WM6 on Sunday June 5 2016 23:12:22 AEST PM
  

 1.139mhz


Probably you mean Mega-Hertz (MHz)  and not mili-Hertz (mHz)?

Is this coil self resonant frequency?


Title: Re: f1a4 coil
Post by: Alex on Monday June 6 2016 15:57:59 AEST PM
Sorry my mistake and yes self resonant


Title: Re: f1a4 coil
Post by: IBGold on Monday June 6 2016 16:15:13 AEST PM
  
Thanks Ian dos it make much difference whether the start coil wire or the end one is used in the centre conductor
I really don't know I have always used the start of winding to coax center and always wind in a clockwise direction whether it makes any difference I don't know it is just what I have always done I have asked the Guru's and never got an answer maybe Techno Bob could make a comment.

Regards, Ian ::62::


Title: Re: f1a4 coil
Post by: Alex on Monday June 6 2016 19:29:44 AEST PM
thanks Ian .I thought i would ask i have one lead to short


Title: Re: f1a4 coil
Post by: Alex on Sunday June 12 2016 19:19:27 AEST PM
Hello again .Ill take off my hat to all the sucssesfull minelab coil builders. My first attempt i wasnt happy with . second one no good third one was a real dogs breakfast .My fourth attempt reads .4 ohms 1441 Mhz but i only have 275 uh i could tighten it up a bit but do you think it would work . the coil size is 9 inch   thanks.


Title: Re: f1a4 coil
Post by: IBGold on Monday June 13 2016 16:14:31 AEST PM
Hi that should work fine and should be very sensitive on small nuggets some of the sensitive commercial coils have inductances down to 260 uh so you are in the ball park.

Regards, Ian  ::62::


Title: Re: f1a4 coil
Post by: Alex on Monday June 13 2016 19:57:09 AEST PM
Thanks again Ian ill try to construct the shield described by Stefan if successful ill attempt a larger one . like the chalenge


Title: Re: f1a4 coil
Post by: IBGold on Tuesday June 14 2016 17:12:50 AEST PM
My condolences You are hooked that is how I started out. ::402::

Regards, Ian. ::62::


Title: Re: f1a4 coil
Post by: gef12 on Tuesday June 14 2016 17:28:11 AEST PM
LIKE???? ????


Title: Re: f1a4 coil
Post by: Alex on Monday July 4 2016 17:07:46 AEST PM
Hi all I need some advise. After reading a post by stefarn about a coil to sensitive for WA goldfeilds i felt the coil i just wound may be the same so i wound another 1.380Mhz 286uh . after winding the sheild i thought that would drop the resonate frequency to about 800Khz .however i came to 1.333Mhz with 111pf coil to sheild. please correct me if i an wrong but from this point my only option would be to fit about 2 mt of coax 16 /per foot pf to bring the resonate frequency to aprox 600 to700 Khz for WA gold fields .the military coil is 364uh 581Khz .the detector ran fine with a coiltech 323uh 693Khz thanks.


Title: Re: f1a4 coil
Post by: Alex on Sunday July 10 2016 21:50:17 AEST PM
Hi all Have had success with the coil .works well thanks to past experiments by members . Could someone explain why the inductance rose from 286uh to 324 after fitting the coax .is that normal.


Title: Re: f1a4 coil
Post by: WM6 on Monday July 11 2016 04:38:24 AEST AM
  
Could someone explain why the inductance rose from 286uh to 324 after fitting the coax .is that normal.

It is normal.
Cable is part of coil windings, it prolong coil wire and by this coil inductance go up somewhat.


Title: Re: f1a4 coil
Post by: Alex on Monday July 11 2016 18:39:41 AEST PM
Thanks WM6 that also explains why the military coils inductance is so high


Title: Re: f1a4 coil
Post by: Doug on Tuesday July 12 2016 12:00:13 AEST PM
Coax Inductance
Calculate the Inductance of a Coax Cable
https://www.eeweb.com/toolbox/coax-inductance
https://www.youtube.com/watch?v=WjHKcgOGdRc
doug ::419::


Title: Re: f1a4 coil
Post by: Stefan on Friday August 12 2016 12:03:54 AEST PM
Hi Alex,

Can’t explain why the resonant frequency  went up after the coax was connected.  Normally the resonant frequency will go down as you have added the capacitance of the coax to the coil.  I’ll get to that shortly.  Suggest you backtrack to what you did with the coil when you connected the coax to the coil leads. If you tightened up the coil bundle then there will be some increase in the inductance but not to the extent you noted.  Also make sure that when you measure the capacitance of the coil you keep the coil well clear of any metallic material especially steel.

Now back to the coax:
The capacitance of the coax will be much greater than the inductance, so capacitance effects on the coil with the introduction of the coax will have the greater effect and will lower the resonant frequency of a   coil. 
This is why us coil builders like to keep the inter-winding capacitance of the coil, the shield capacitance and coax capacitance to a minimum.  This is inherent to the coil construction practice used by the coil builder.

Next parameter you should consider is the Q of the coil. This is the quality or the gain of a coil at a measured frequency. Traditionally the Q of a coil was measured at a frequency of 1000 hz but many capacitance meters will measure at 100khz or higher.  The Q of a coil is defined as the reactive resistance of the coil divided by the dc ohms resistance of the coil.

The measured  Q helps you construct coils with the same gain irrespective of the size of the coil.  The total coil resistance R is equal to the actual resistance of the coil plus the resistance introduced by the  coax.  Increasing the total resistance decreases  the  Q of the coil.
The original Minelab mono coils had a Q of 4.5 measured at 1Khz. The current coils probably have a   Q much less than this.

I hope this info helps you in your coil endeavours.

Stefan


Title: Re: f1a4 coil
Post by: Alex on Friday August 12 2016 22:15:58 AEST PM
Thanks Stefarn .Ill give that some thought .I recently tried the coil in WA goldfields and it seemed to work well even though no luck .In a few weeks ill start attempting an 18 inch . I did notice the coil preformed much better on the small settings than on the large setting .This f1a4 is a mod 2 Jack Lange


Title: Re: f1a4 coil
Post by: WM6 on Friday August 12 2016 23:50:55 AEST PM
Hi Alex

How did you measure coil resonant frequency? By galvanic coupling testing probe to coil or loosely by inductive coupling?
By galvanic coupling you can add test probe leads capacitance to your measurement and get improper results.
You need to take in consideration that in some cases cable capacitance (depend on cable used and sort of its connection to coil)
can be in serial to coil parasitic capacitance and not in parallel as well that with improper measurement we can easy measure
some of parasitic frequency instead of right resonant one.


Title: Re: f1a4 coil
Post by: Alex on Saturday August 13 2016 21:16:50 AEST PM
Thanks WM6 . i feel the rise in the inductance may be from incorrect measuring inside the house on a wood table with metal frame and tightening of the coil after wrapping the shield tape .The measuring devices i used was a Lc 100a meter ebay and  http://www.robkalmeijer.nl/techniek/...e48/index.html circuit connected to a Vichy vc97 frequency meter . I have since measured the coil in the paddock away from everything keeping the leads apart and got 686.1 khz 323.1uh .I havent measured the Q i dont have a meter. Perhaps its a good idea for the next coil .any suggestions .Im going away on tuesday for 3 weeks so ill start when i get back.


Title: Re: f1a4 coil
Post by: Alex on Saturday August 13 2016 22:21:42 AEST PM
Sorry link didn't work try  http://www.robkalmeijer.nl/techniek/electronica/radiotechniek/hambladen/73/1990/09/page48/index.html   


Title: Re: f1a4 coil
Post by: Alex on Wednesday November 9 2016 14:16:12 AEDT PM
Hello again just used the coil recently constructed in the wa gold fields with some  success 9.5 gram nugget. I feel the coil is a bit noisy, ground balancing about every min and at times i had to wind the gain dial back from full to about half . I don't have a Q meter so i calculated the Q with 2 pi Fr I/ohms then compared it with other coils on geotech plus a coiltech coil and the original army coil. From this i think the coil Q could be about 4.5 The army coil could be about 4.3 I plan to use this method i want to construct an 18 inch to the same Q as the original army coil. Do members think this will work


Title: Re: f1a4 coil
Post by: WM6 on Wednesday November 9 2016 20:40:15 AEDT PM
Hi Alex
It is hard to say how your new 18" coil will perform.
Coil Q is not only factor to imply, there is total resistance and parasitic coil capacitance too.
And coil should be well adapted to detector input circuit (properly damped).
You need to try and see outcome.


Title: Re: f1a4 coil
Post by: Alex on Wednesday November 9 2016 21:16:28 AEDT PM
Thanks WM6 .I thought if i mached the inductance resonate frequency capacitance and ohms as close as possible to the original 8 inch coil;then use those results to calculate the Q factor to try and get the same  I dont have a oscillow scope .Im using .2mm x36 or so strands to adjust the ohms.I relise the ohms increase as frequency goes up but i thought this way might get it close.any thoughts? thanks


Title: Re: f1a4 coil
Post by: WM6 on Wednesday November 9 2016 22:35:05 AEDT PM
  

I relise the ohms increase as frequency goes up but i thought this way might get it close.any thoughts?


Generally this is due so called "skin effect".
Practically you need more wire surface to lower total resistance.
With more wire surface "parallel resistor" effect appear.
More wire surface you get with multi-strand wire (Litz wire).
This way you can somewhat control total resistance at given higher frequency (no effect at low frequency).


Title: Re: f1a4 coil
Post by: Alex on Wednesday November 9 2016 23:06:05 AEDT PM
Thanks Wm6  .So what your saying is because a f1a4 minelab detector operates at low frequencys .i have no need of a Q meter i could get away with calculating the Q with the known resonate frequency inductance and the ohms 2pi.f.l/ohms


Title: Re: f1a4 coil
Post by: WM6 on Thursday November 10 2016 00:12:24 AEDT AM
Q is important to get tank (LC) circuit to oscillate.
To low Q will not allow tank circuit to oscillate (depend on frequency of course).

With (most) PI technology we use pure (square like) pulses to drive our sensor (coil).
If sensor would be pure R, then no Q factor implied in its functionality.

But this is not the case, cause coil has inductive as well capacitive components - it is LC(R) tank circuit.

When we drive LC tank circuit with pulse, those pulse "fall apart" or become composed out of sinusoidal signals.
Those by pulse created sinusoidal signals are composed out of main resonant signal with many added low and high harmonics signals.

Resonant LC tank (coil) sinusoidal signal depend mainly of coil LC value and not so much on (mostly low) pulse changing rate.
This way we are back to coil Q, which become somewhat considerable working factor in more complex PI technology.

Practically speaking: you can drive your coil by 100pps (100"Hz") pulses rate, but your coil has self resonant frequency at 500kHz and this
is important to establish coil parasitic capacitance at least and by this correct coil damping and adapting to detector RX circuit.

So, from your f1a4 point of view, to correct accept you new coil, such coil should be made as much like original by parameters: L, C (coil own parasitic capacitance), Z (impedance) and coil Q factor. In this case new coil will be seen by f1a4 as genuine coil and no inner f1a4 circuit adaptation will be needed. How to do this is another story, very hard without instrument to perform different measurements. Without instruments, the only way is "try and error" way - most usual in amateur world.


Title: Re: f1a4 coil
Post by: IBGold on Thursday November 10 2016 16:05:28 AEDT PM
  
Thanks WM6 .I thought if i mached the inductance resonate frequency capacitance and ohms as close as possible to the original 8 inch coil;then use those results to calculate the Q factor to try and get the same  I dont have a oscillow scope .Im using .2mm x36 or so strands to adjust the ohms.I relise the ohms increase as frequency goes up but i thought this way might get it close.any thoughts? thanks

Hi Alex,
You are going about it the right way and your 36 strands of 0.2 mm is what I use for an 18" coil the trick is a tight coil bundle I lace mine at 10 mm centers and have a 12 mm spacing minimum to the shielding to minimize coil to shield capacitance I have not tried one of my coils on the F1A4 yet but when I get time when I have got the splint of my left hand and can use it again (4 more weeks) I will try and let you know how I go.

Regards, Ian. ::62::


Title: Re: f1a4 coil
Post by: Alex on Thursday November 10 2016 20:39:00 AEDT PM
Thanks Ian and Wm6 for your input. Ill look forward to hearing from you Ian. When i made the 11 inch i based the coil parameters on a coiltech 14 x9 from a gp3000 .i got all parameters very close . Maybe if i tried the coil tech in the goldfields it could be noisy with the f1a4.Ill copy the 8 inch army coil  for the 18 inch parameters.The army coil is 363 uh ,i thought that was high but every way i check it i get the same reading .Ian do you bulk wind your 18 inch or use a spacer as Stephan does with his 12 inch  thanks again.


Title: Re: f1a4 coil
Post by: WM6 on Thursday November 10 2016 23:22:04 AEDT PM
  

Hi Alex,
You are going about it the right way and your 36 strands of 0.2 mm is what I use for an 18" coil the trick is a tight coil bundle I lace mine at 10 mm centers and have a 12 mm spacing minimum to the shielding to minimize coil to shield capacitance I have not tried one of my coils on the F1A4 yet but when I get time when I have got the splint of my left hand and can use it again (4 more weeks) I will try and let you know how I go.

Regards, Ian. ::62::

Hi Ian

Curious, what would be resonant frequency of such 18" coil using 36 strands wire?

Have you ever been determined (measured) it?

Regards and best wishes to your great work with coils.


Title: Re: f1a4 coil
Post by: IBGold on Friday November 11 2016 17:14:27 AEDT PM
Alex, I make my wire from the required amount of .2 mm enameled copper wire when the wire is made I put 1 or two layers of  clear heat shrink tubing I buy it in 15 meter lengths very time consuming but it seems to do the job once the coil bundle is wound and tightly laced I put it in a Styrofoam former which I make in two halves and bond together I then apply the shielding over the former then put that in the housing which I either vacuum form or fabricate from ABS I hope that answers your question.

WM6, Yes I measure the resonant frequency of all my coils depending on the type of wind the resonant frequency of an 18" coil can be from 550 KHz to around 785 KHz as I said depending on construction method and type of winding.

Regards, Ian. ::62::


Title: Re: f1a4 coil
Post by: Alex on Friday November 11 2016 18:55:52 AEDT PM
thanks Ian


Title: Re: f1a4 coil
Post by: WM6 on Saturday November 12 2016 21:11:04 AEDT PM
  

WM6, Yes I measure the resonant frequency of all my coils depending on the type of wind the resonant frequency of an 18" coil can be from 550 KHz to around 785 KHz as I said depending on construction method and type of winding.

Regards, Ian. ::62::

Ian, thanks for info.


Title: Re: f1a4 coil
Post by: Alex on Wednesday December 14 2016 20:41:28 AEDT PM
HI guys I have a question perhaps for Stepharn . For say a 16 inch coil using a shielding tape with .2 mm wire spread evenly across 19 mm tape .Would it be better to wind one 18 meter length or say 6 x3 meter lengths


Title: Re: f1a4 coil
Post by: authere on Thursday December 15 2016 14:32:44 AEDT PM
Hi Alex,

I have made Stephan's shielding and it was quite easy to make it one length to do the job

I used my verandah posts which were 3m apart and to each post connected a bolt with the correct spacings in the thread for the spacings in the shielding

I then ran the wires along the verandah posts thru the threads

I then made a former which I travelled with along the tape to keep the spacings as I set it to the tape

Time consuming but you get there eventually,but to make it in three pieces it would have to have the ends connected and soldered joints build up eddy currents which would negate a lot of hard work

I think it would be a lot easier to do what ML do and coat a sheet of water proof paper and apply one to each side of the coil

Ron(but I am no expert)


Title: Re: f1a4 coil
Post by: IBGold on Thursday December 15 2016 17:24:50 AEDT PM
Hi Alex I use both Stefan's method and commercial Electrodag with Stefan's method I use 24 or 25 mm tape and use a 6.0 meter length of 50 x 25 RHS with the required pitch bolts set  on each end the RHS is held in two vices with one layer of tape held sticky side up on the top of the 25 mm side the wire is then strung and another layer of tape applied over the top time consuming but does the job and I have not needed any more than a six meter length I have even used masking tape with no problems at odd occasions.

Regards, Ian. ::62::


Title: Re: f1a4 coil
Post by: Alex on Thursday December 15 2016 17:35:47 AEDT PM
 Thanks Authere, I used Stepharns sheild on a 11 inch and i found trying to get even spaced wires on a 5 meter length difficult .Your idea using bolts sounds good .Thanks again ill go with the full length . one more thing ,roughly how wide would you space the shield wires on a 16 inch bundle wound about 10 mm with about 15 mm polystyrene spacer


Title: Re: f1a4 coil
Post by: Alex on Thursday December 15 2016 17:41:20 AEDT PM
Thanks Ian . Which is better aquadag or stepharns


Title: Re: f1a4 coil
Post by: Alex on Thursday December 15 2016 17:49:33 AEDT PM
opps  i meant electrodag


Title: Re: f1a4 coil
Post by: authere 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


Title: Re: f1a4 coil
Post by: Alex 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


Title: Re: f1a4 coil
Post by: Alex 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


Title: Re: f1a4 coil
Post by: greylourie 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 ?


Title: Re: f1a4 coil
Post by: Alex on Tuesday December 20 2016 20:29:37 AEDT PM
Thanks for your reply greylourie .mary xmas


Title: Re: f1a4 coil
Post by: IBGold 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. ::62::


Title: Re: f1a4 coil
Post by: authere 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


Title: Re: f1a4 coil
Post by: Alex on Wednesday December 21 2016 21:45:24 AEDT PM
Thanks for the help guys .have a mary xmas


Title: Re: f1a4 coil
Post by: greylourie 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.


Title: Re: f1a4 coil
Post by: Alex 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


Title: Re: f1a4 coil
Post by: authere 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


Title: Re: f1a4 coil
Post by: greylourie 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." (http://www.geotech1.com/forums/showthread.php?13124-Mono-Coil-construction-help&p=54935#post54935)

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.


Title: Re: f1a4 coil
Post by: Alex 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


Title: Re: f1a4 coil
Post by: Alex on Saturday January 7 2017 23:32:26 AEDT PM
Thanks Jon. It is a challenge


Title: Re: f1a4 coil
Post by: authere 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


Title: Re: f1a4 coil
Post by: greylourie 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.


Title: Re: f1a4 coil
Post by: Alex on Sunday January 8 2017 09:54:27 AEDT AM
way to go Ron ;fishing surfing all good for brain strain