XP deus coil modification

[golfnut]

Do you put the turns thru with straight pipe and then bend up?

[Skippy]

If you make that 4 inch coil, with the coil shape shown you should only expect a 2% inductance drop (from circular), so only aim for +2% extra L when using the coil calculator.

[Henrikras]

That will Be funny to see what Inductance it ends up with... I will tell you later this week.
(If this tube Project will work.) (I sure it will take long time to do the Winding).
Henrik.

[golfnut]

Its a shame the stock 3030 6" probably wouldnt work for your project - it would be so much quicker S

[Henrikras]

yeah... That had been nice Golfnut. And a little exspensive buying a CTX coil just to open it up and use the Shell.
I will find out a way to make a 6" shell, Maybee by two coil covers ! Could work.
Henrik.

[Henrikras]

Hi.
So much for the theoretical calculations and ideas. Did a test with 0.25 wire.
To get 10.4 mH it should had been 246 turns + 2-4% - I only got space in the plastic tube to 255 turns and ended with 9.8 mH and 25.2 ohm. One size bigger Plastic tube and 0.28 wire will Be needed. Back to the order office.
It must Be this small coil size, there is causing that I must add 5-6%.
No Big deal I'm in no hurry with this project.
Henrik

[Skippy]

It could be the fine detail that's causing the error, things like the radius actually is 49mm, not the 50mm (or whatever) you did calculations for. Binding up the bundle tightly increases coupling between each strand, increasing L by 1 or 2%. Also, is your L meter actually a good accurate one? Have you checked it on known inductors, etc, or compared it to a quality lab one? That might account for theory and practice not agreeing. I found Brooks formula worked pretty well, though it is actually for a rectangular/square section coil, with the wires in neat rows, not for a round bundle, with the wires taking on a 'hexagonal close packed' arrangement.
Edit: I've just laboriously resized your pics of the 4 inch coil, blu-tacked wire to my monitor screen, and worked out a mean circumference of 252mm. This gives a mean radius of 40mm for the circular coil. putting into the Qoil Qalculator: inner radius=38mm, (mean =40, outside=42) with 0.25mm wire, 258 Turns gives 10.65mH (=10.4mH + 2%). Whaddya think?
Just an idea - could you cut slots part-way into the outer edge of your plexiglass tubes at 8 points, then bind up the wire bundle with cotton thread through these slots (if that makes sense)

[Henrikras]

You nailed Skippy... Small error by me causing it.
1. It was Very hard to take off the coil of the Wooden form..( Lower diameter.)
2. the windings got a little lose and had to use tape to hold them, after it got off.
3. The plastic tube must Be made 1-2 mm larger next time, because all the wires do pres the plastic, and it ends up with smaller diameter.
But good to learn all this.
Do you agree that I should try to hold the TX down close to the 21 ohm or even less If its posible ! 19-22 ohm will Be my target.. I dont like it going up like this test today (25.2 ohm) and it had properly ended with 27-28 ohm, with some more windings to reach 10.4 mH.
I know what to do... A. Order some 0.28 mm wire or B. make a new plastic tube form a little larger and with sharper corners to get a little more circumference. It depent what you will say ! Is it worth a try with a TX ending up at 24-25 ohm ? (Properly limit with 0.25)
Going on a Detector trip saturday and Maybee sunday.. Thats why I off line. (Late answers).
Ps. My instrument is okay... And If I make a LC resonans / scope and tone generator test and use this: http://www.siversima.com/rf-calculat...FfB3cAodsAgAzg. - its close to same result.
Henrik.

[Skippy]

I don't know. That's one reason i suggested making the RX first, it's not so critical on the R measurement. Then you can make the more-critical TX better, by learning from the RX experiment. Here's an experiment - accurately measure the winding resistance. Calculate what lenght of wire this is equivalent to, then divide that by the number of turns, gives you the mean circumference. See how that differs from 252mm.

[Henrikras]

I found this : http://www.pronine.ca/qbw.htm
Can give a little idea to the Q factor.

[Henrikras]

Hi all.
Some scope with TX 1-2-3 at the 11 khz and the 17 khz area. (See pictures).
One Very good thing to know; The TX adjustment will only work in middle Freq. (11.494 - 17.241).. and the Deus will only use TX2 if someone try to change Freq. at the Expert menu. (See the 11 khz scope pictures right and left, the same amplitude at the lower and the highest Freq.. But at the middle Freq. the TX is working. (This coil properly got its peak at 11.494 khz.)
But at 17 khz is different ; The 17.123 / 17.241 is closely the same high peak like TX3. And the high Freq. 17.361 got similar like TX 1.8 or something like that.
I hope this could Be usefull to other Deus owners. (TX power is not linear - Freq. got a issue)
Henrik.

[Henrikras]

Step 5 is ready... Electronic and battery is in a box, and Cable from Stock coil with plug is done.
The best of all... Ist working pretty good. . To Dark out side now, but in lab no problem at all. Even sens. 99 still calm and pretty good airtest depht. All the disc. Settings and the ID perfect like the Stock coil wireless.
Tomorrow out to the testbed.. So fare so good.
Henrik.

[Henrikras]

Hi Once more.
Step 6. Been out testing the Stock 11x13" coil with electronic at the stem.. First try GB gave some problems, then back to the lab and shortne the cable. That help a lot. Somebody recommend short cable and that was true.
The coil is working really good. Made some compair with my other coils and Very small lose If any.
picture shows where I had place the electronic and the coil sizes to give a look how small 6" and 5x8" is.
Henrik

[Funfinder]

Step 5 is ready... Electronic and battery is in a box, and Cable from Stock coil with plug is done.
The best of all... Ist working pretty good. . To Dark out side now, but in lab no problem at all. Even sens. 99 still calm and pretty good airtest depht. All the disc. Settings and the ID perfect like the Stock coil wireless.
Tomorrow out to the testbed.. So fare so good.
Henrik.

Good job, Henrikas incl. all who gave you some tips.
A smaller coil will be always more stable compared to larger ones which always will pick up more "interference" from soil or electro-smog.

Of course for me the question remains how useful is this "wireless"-coil at all if the weight including the accu of this box is already almost the
same "heavy" as a complete usual detection-electronic? 100-300 grams more and you could attach a complete unit there instead this transceiver unit.

With this small coil you will get a real good detection-signal-stability if you use a stable compound-glue and hard-cover or whatever for the coil
but the coil-cable will disturb this a bit if touched by grass or other stuff and: this 3,7v accu is absolutly not really THE high-coil-power solution.

How much mA drags (consumes) the coil-circuit and how much the transceiver- and signal-processing-unit?!

The much better solution for the XP Deus would be if it contains 4x 5000mA LiPo accus directly at the handle because placed there it gives
the lightest weight while sweeping the coil! This way the coil really would get a reasonable enough amount of power.
For the little coil it doesn't matter alot but for the 35cm XP-Deus coil this single accu for shure is much too weak for real depth-penetration.

The larger the coil the stronger the coils-EM-field gets thinned out or disturbed if it is not powerful enough - no matter how highly sensitive
(and therefore even more prone to electro-smog etc.) the analysis-circuit is. Compare it with the shine of a lighthouse through thick fog and rain,
a little candle you won't see very far if there is fog, no matter how good your field-glasses (= the analysis circuit) is.

But of course you can't modify the coils-EM-field-strenght so you have to stick with the default values.
At least your work could be a very good inspriation for the XP-company to throw such a small coil onto the market.
Its imaginable that around 15% of all XP-deus users would be interested in having such a coil. But you are the first now! Congrats.

[Henrikras]

Thanks Funfinder....
Its Very good to get some feed back.
I'll Be back with some more work and test.
Henrik