Help to make a eliptical DD coil design.

[dfbowers]

Nice video. Very impressive on the VDI. I will have to give that shell a try on the IDX.

[golfnut]

You will be working contract for XP next !!!

Really well done on this work - top effort

[Henrikras]

Thanks - but with out your help Golfnut, Don and Skippy, this couldn't had Be made.
But Don... This Shell you made is in a perfect balance, Not to narrow and not to long. You will love it at your IDX.
I got no idea about this, but because the TX got 0.31 mm wire and the RX 0.18 mm wire, and they are made from same form, the TX is a little larger.. I got 1-2 mm air from the TX to the Shell and 3-4 mm air at the RX side.. That little off balance size could Be my lucky punch.. Dont know but why else is this coil working so nice, and I had to stroggle so much with the 7" coil !!!
Allso look at the distance in the middle... 1 cm between the RX and the TX, thats a awesome sharpness.
Maybee my Deus electronic unit just love to go smaller, and it all comes how it is programed at the XP factory !! Never mind I'm got a Big smile now and keep that until the shielding problems start. LOL.
Thanks for your support.
Henrik.

[mohandes]

It did raise the bar a little on trimming though.

hi Don
can you teach me to make it.
regards

[dfbowers]

Mohandes,
Sure.. I can post any details here. Just let me know what you would like me to share.
Basically I traced Henrik's pattern onto wood and cut it with a Sabre saw. I made one copy on
my vacuum table out of plastic, epoxy filled that one and used it as a pattern for the bottom half.
That way, the bottom half is a perfect fit. I can post some pics of the process when I make
another run of shells in a few days.
Don.

[mohandes]

Mohandes,
Sure.. I can post any details here. Just let me know what you would like me to share.
Basically I traced Henrik's pattern onto wood and cut it with a Sabre saw. I made one copy on
my vacuum table out of plastic, epoxy filled that one and used it as a pattern for the bottom half.
That way, the bottom half is a perfect fit. I can post some pics of the process when I make
another run of shells in a few days.
Don.

thanks Don
if you can put your teaching in PDF file more better .
regards

[dfbowers]

thanks Don
if you can put your teaching in PDF file more better .
regards

You can download some details here: https://sites.google.com/site/dbcoil...vacuum-forming Also, see the .pdf on building a vacuum forming table and two stage vacuum forming. Don

[beerguy]

I would buy a couple once they are on your site.

[Henrikras]

Ready to go out to the hot spot.
This DB shell eliptical 5.5"x7" Deus coil is made with same shielding like my 7" Deus coil allso made in a DB Shell.
I hope it will work.. Some test at Home looks good, but you never know... Reel invoirment is different.
See you later.
Henrik

[golfnut]

That could be the most useful detector in the world at the moment for iron contaminated sites. We saw it here!

[Henrikras]

Thanks Gulfnut... .
Here is the days result and my honest opinion.
The benefit to use a smaller coil, going down from a 9" coil to a 7" coil and like to day a eliptical 5.5"-7" coil, (using a Deus Detector) ISN'T much. I made a test Very similar to the signals I'm getting at my field, and came to that conclusion.
This coil size quenstretion Its a balance; coverage / dept / masking / clear signals / respond - you know what try to say.
Yes my new smaller coil will find more, but not much, because the iron is masking more that I thought. Remember allso this theory ! Smaller coil less dept and therefore less iron / masking problems, but allso less good objects.
Made a video.. and that will show you what I'm trying to say.. Injoy and any comments are mustly Welcome.
http://www.youtube.com/watch?v=nMXHncRvL9w&sns=em

Henrik

[golfnut]

I see it is a trade off. Im unsure why the masking was like it was.. I have seen a demo from freinds deus and he had iron and coin in his hand and a wave gave both tones.

Not sure which program it was - but it got the coin and the nail.. Burrrr Bip


I got the impression the new coil was not so deep. You would expect that


I use elliptical and the depth in the ground is about 80% of the narrow dimension of coil - so you may expect 5" max withthe deus ~approx


I get about 7" max on an 8 1/2 Hunter.


With the hunter I do get more signals in iron due to blade illumination - if I get a squeak, I rotate 90 and look for a way into the target.


I agree your 9 sounded best.


But the ellipse should find surface coins 1,2,3 inch down - very close to iron.. and be more in line with some of your initial requirements - just not the depth ( most stuff air tests real well, but out there its tough ) as you well know


Try a retest with coin 2" down, and put the stones on the nails again,

I think the deus makes people swing like an axe murderer - cut this right back to slow - you can afford this time due to relatively small area and you may get a few more - should get you to 100 coins !


I do some roman work with same contamination , easily get 5 irons in single sweep - machines were never considered for this especially outside of europe

On the river thames in london they use 3" coils as there is lots of iron, but they are only allowed to dig 4" down - so OK.

Small is good, just keep at it and slow it up a little and tell us what happens, dont be too dissappointed.


There may only be 5 coins left in there!!!
S

[Skippy]

"any comments are mustly Welcome"
The two obvious ones:
Your iron contamination isn't that severe, so the standard 9 inch coil probably manages OK.

You should consider increasing the pre-amp gain, x2 would be a decent start. Problem is you wan't to use the electronics with big 15 inch coils as well. Plus you may have null problems, though these could be sorted out.

[Henrikras]

"any comments are mustly Welcome"
The two obvious ones:
Your iron contamination isn't that severe, so the standard 9 inch coil probably manages OK.

You should consider increasing the pre-amp gain, x2 would be a decent start. Problem is you wan't to use the electronics with big 15 inch coils as well. Plus you may have null problems, though these could be sorted out.

NO NULL problems - this coil ended close to a perfect Null even better than the 7" coil some weeks ago. ( >10mv PP)
Yes Maybee electronic issue ! That is made to the Big coil.

Playing with the preamp wouldn't Be easy.. SMD component and need a microscope to do this kind of work.

[Skippy]

"Yes Maybee electronic issue ! That is made to the Big coil."
I think you misunderstood. I meant that if you were ONLY intending to use this electronics with the small 7 x 5 / 7 inch coils, you could permanently increase the gain.....but you are also trying to make a 15 inch coil, are you not? For this, you DON'T want extra gain. And making the gain switchable is not really easy to do, though not impossible, I have a few ideas...