Well here we go

[Largesarge]

The Eagle dropped a package in my mailbox today and lo and behold there was a circuit card in it. I got it back in the case and all hooked up, now I have to make sure the batteries are charged up and hook up a coil and I'll be ready.

Ahh but wait, there's that little thing called the weather. If somebody would kindly turn off the bloody sprinkler and turn on the heat maybe I could get out and do a bit of test swinging.

[Largesarge]

Well folksies since I got the board back from gary we have had rain, rain and more rain. When you think things are going to dry out it starts up again.

Then several weeks ago I drop my copious weight on my right knee severly it and straining the musculature around it.


The is now all healed and I wake up this morning to 2 inches of snow on the ground. This can't be happening to me, I feel star crossed. Maybe this weekend will warmup and dry out enough to do some testing.

[MojaveRed]

Damn Sarge,

You have to move down here to the Mojave Desert.

Hope your knee's healed.

Let us know how your machine works -- if you ever make it out the door! I'm just starting the adjustment/calibration phase on my first, a Hammerhead, so I'm interested in hearing about the experiences of other builders, regardless of machine.

Best of luck.

[Largesarge]

If it weren't for the heat Red I'd do it, but I'm afraid my MS would give me fits. I do need to get to someplace drier though, this rain is driving me nuts.


I did get it out for just a little bit the other day but results weren't spectacular. It picked up the nails in my deck at about 3 inches and the cast iron umbrella base and the step ladder from fourteen to sixteen inches but they are large items. I've got to spend more time working with the PW, Delay and RT, I'm sure I'll find the right combo.

BTW the above was done with a rectangular coil, Gary says he didn't design it with a rect. in mind, so I need to do up a circular coil and work from there.

[MojaveRed]

Rectangular coils are an interest of mine. I'd be interested in hearing about your coil, the specs and such; size, inductance , resistance, etc.

[Largesarge]

Red, the coil is about 28 turns of 22ga. mag wire for a 16X4 shell that I got fron Charles (NY) so it's a little bit smaller than that. It measures out at 410uH and 1.35 Ohms. Its' unshielded as Gary suggested not to.


I've got an 8" scrmble wound coil that Gary suggested for testing the head before I sent it off to him to fix my screw ups. I'm going to mount that on something and see how that works.

TTFN

[chemelec]

Dennis, I did make one large Rectangular Coil, Outside dimensions measuring 9" X 36".

It had 20 turns 18AWG wire with a measured inductance of 566 uH.
It was Flat Wound simular to the way I make my Radial Coils.
DC Resistance is about 0.7 Ohms

But I was Not pleased with the results at all.
Possibly I should have reduced the turns for a Lower Inductance and tried it again.

Take care..........Gary

[chemelec]

Here is a Picture of that coil I made.I Just added Taps to the coil to try different numbers of turns and Inductance values.
I will test it out in a few days.

I Previously did this experiment with one of my flat Round coils. It worked quite well to determine Optimum turns and inductance for a particular coil size.

And since the Unused turns don't connect to anything they don't appear to interfer with the final test results. At least Not on a PI Detector

Gary

[chemelec]

Doing a Quick test with this coil suspended 3 feet from my basement ceiling and connected to my pulse-1 detector, here are some results.

Both the 315uH and the 394uH taps gave the Best and roughly Equil results.

A Canadian Quarter (Made of Nickel Metal) at only 5 Inches.
A 5 inch by 6 inch aluminum square at 16 Inches.
A 24 Inch by 24 Inch piece of Raw PCB material at 50 Inches.
A Rectangular 4 liter Steel Can (Area parallel to coil was 6 Inches by 10 Inches) and the detection Distance was 26 Inches.

Still not really impressed.......Gary

[MojaveRed]

Gary,

What is the "width" of the windings, that is, the distance from the outer winding to the inner winding of your flat rectangular coil? Presumably, 9" X 36" refers to the "outer" dimensions.

Is there any spacing between the windings or are they adjacent, with the thickness of the enamel separating them?

Are you able to say anything about resonant frequency and inferred capacitance at this point?

Thanks.

[chemelec]

Gary,

What is the "width" of the windings, that is, the distance from the outer winding to the inner winding of your flat rectangular coil? Presumably, 9" X 36" refers to the "outer" dimensions.

Is there any spacing between the windings or are they adjacent, with the thickness of the enamel separating them?

Are you able to say anything about resonant frequency and inferred capacitance at this point?

Thanks.

Presumably, 9" X 36" refers to the "outer" dimensions.

Not quite sure what you mean by "Presumably".
"It is those dimensions".

The typical Coil width is .875 inches. I Tried to wind each turn Tight together, but there are small gaps in some places.

Free Air Resonance between the inner-most lead to the outer lead (568 uH winding) is 902 Khz. That represents an internal Capacitance of 54.8 Pf.

The Backing Plate for this coil is a piece of .030 inch, Glass Epoxy PCB Material with the Copper Removed.

Gary

[chemelec]

Just for Curosity, I wound another rectangular coil, 4.5 inches by 18 inches.
21 1/2 turns # 20 AWG, Flat Wound like the other one.
Inductance was 255uH and Free Air Resonance was 2.048 Mhz.
Doing a Quick test with this coil also suspended fom my basement ceiling and connected to my pulse-1 detector, here are the results.

A Canadian Quarter (Made of Nickel Metal) at about 8 Inches.
A 24 Inch by 24 Inch piece of Raw PCB material at 28 Inches.
A Rectangular 4 liter Steel Can (Area parallel to coil was 6 Inches by 10 Inches) and the detection Distance was 23 Inches.

Gary

[MojaveRed]

Gary,

By 'presumably' I was refering to the fact that in some discussions of spiral wound coils the dimensions are given as a "mean" length and width, measured from center-to-center of the windings.

I presumed you didn't do that - and I am correct.

[chemelec]

Gary,

By 'presumably' I was refering to the fact that in some discussions of spiral wound coils the dimensions are given as a "mean" length and width, measured from center-to-center of the windings.

I presumed you didn't do that - and I am correct.

I always use the Outer Most Dimensions.....Gary

[J_Player]

Coil size? Doh.....

.