Barracuda Legend Kit Problems

[kt315]

ok i used a Fluke 87 True RMS meter is this multimeter to basic?

ok so i have this affect as i have no shielding yet

use this Fluke. was on my former job. perfect device.

[Koala]

ooooo and i noticed an old thread that a guy was having an issue with the coil moving in free air if i pick up the coil and swing it in free air i get a beep at the end of each swing? what is that about?

Easy to pick up any cable movement. Been several people with a slight beep at the end of sweep. Last time someone was swapping Q3 and Q4 but never got back with the result?

[Impulse]

Hey old cart i have a large ish gold chain and it was picking it up (very close) but now i cannot get it to work i really want this to work , i have the o-scope working now but it is a fluke 196c and i have no idea how to get it to where it should be, can you help? when i adjust the bottom (blue w203) delay pot it does not seem to make any odds where it is it doesnt make the tone louder.

I can borrow a Fluke 196e from work (while its still open) i do not have an idea how to set up it though

hey koala yer i know i would like some sort of answer just to close the thread mabe he gave up? (i will not)

[Old cart]

ok i used a Fluke 87 True RMS meter is this multimeter to basic?

ok so i have this affect as i have no shielding yet

Yes for a comparative measurement it is fine it has frequency response to 20KHz.

[Old cart]

is the sinusoidal signal clearly for you that I mean? i ask you again because I can not imagine how you measure rectangular 50us pulse with 1/600s period with the high accuracy by primitive chinese multimeter.

KT I do not use a cheap meter. I didn't say DC voltage and that is wrong, I should have said true RMS AC. It has frequency response to 20Khz at .4% accuracy.That is the spec for sine waves. A 50uS rectangular pulse has a sinx/ x spectrum with the first zero in the response at 20Khz and frequency components out at least 100KHz depending upon the rise time. I do NOT claim this is an accurate measurement, for that I use a 400 MHz scope. It was only to see what the approximate duty cycle of the pulse was because impulse did not have working scope handy at the time. By using Simple math it is easy to calculate the rough RMS voltage of a rectangular waveform.
For example a 1 volt 50uS pulse occurring every 1mS would have an duty cycle of 5% and therefor the average value would be 1x5% or 20mV. This would also have an RMS value of 20mV because of the rectangular shape. A true RMS DMM with a frequency response flat to 100KHz would read this pretty accurately. Though such a DMM is rare they do exist.

[Impulse]

hey old cart, ok thank you i thought i was using Chinese junk, if i buy the ebay scope is it going to to be ok for this application?

http://www.ebay.co.uk/itm/ARM-NANO-D...EAAOxy4c5RsZUd

[Old cart]

hey guys sorry i havent replyed i have had some work issues the whole site i work on is being shutdown . So i have ordered a roll of 0.5mm enamelled copper wire i will build a coil once it gets here and i will buy a scope once i get paid is this one any good?

http://www.ebay.co.uk/itm/ARM-NANO-D...EAAOxy4c5RsZUd

old cart i dont have an iphone or pad i can down load skype (thank you for being so generous as to help me like this!)

im going to build a 10" coil for coinage and wreckage

once i have bult the coil i will take pics and state the resistance then go from there, using the forum calc i get,

0.5mm Dia wire 124mm inner radius and 20 turns - 0.309mH inductance is this about right as i have read that 300 is about right for this board?

that scope should be Ok for many measurements but DO NOT put it directly across the coil with the probe in X11 position. It can take only 80 volts and the coil can easily reach hundreds of volts. Also it has an input impedance of 500K ohm which is non -standard. This means it will not work correctly with standard x10 probes. It does appear to come with a custom probe that can be switched to X11 or x10 so it should be fine.

[Impulse]

Hey guys I have just made a coil 24 wraps 0.5mm mono loop I have it all connected and I can get it to pick up my gold ring at 20 cm if I move the coil I get a detection tone so how do I shield the coil to stop this? Here's a pic of what I have so far

[Old cart]

Hey guys I have just made a coil 24 wraps 0.5mm mono loop I have it all connected and I can get it to pick up my gold ring at 20 cm if I move the coil I get a detection tone so how do I shield the coil to stop this? Here's a pic of what I have so far
[ATTACH]35204[/ATTACH]

Do you have the coil sitting on the floor? There are often metal bars in the floor so moving the coil can cause a tone. Put the coil on a wooden bench with no nails or screws or a cardboard box with no staples and try the test again. If the coils gets near any metal it can overload the circuit and ruin the response. You must perform all adjustments with the coil at least 40cm away from any metal. Even farther is better. Just moving the coil slowly, even it is not shielded, will not generally cause a response.

[Impulse]

I have the setup on floor at the moment as that was the only area i could find in the house that was out of the way, i will move to the garden once it stops raining. Even if i pick the coil up and move it i get a response the any small movement is enough to set it off.

[Impulse]

ok i have sorted the coil movement issue it was the coil cable movement causing the response issue yay something simple to fix!

[Impulse]

hey guys ok i thought i had solved the movement issue but i havent i took it all outside and the wind sets it off! any movement left right up down or twist or even a gust of wind! i dont understand what is happening?

[Old cart]

Is the cable still moving? I would not think the wind could case such an effect unless you have metal dust blowing in the air!��

[Impulse]

no the cable is taped to a length of wood! that’s what i do not understand, even if i leave it alone when the wind gusts the board BEEPS! (so close to throwing it over the fence at this point) I’m lost as to what to do with it now i even looked at off the shelf (££££) detectors i will set the coil in resin so it cannot move EVER again and i am going to buy one of these,

http://www.ebay.co.uk/itm/Hantek-602...gAAOSwyQtV39Im

so i can set the delay to the exact point where it is supposed to be rather than guessing.

[Old cart]

It could be a couple of things. Electrical interference, coil windings moving, sampling set too early. Sampling clock jitter or a noisy op amp. I would not pot the coil but you can tape the windings.
BTW that looks like a better scope.