IDX-PRO+VDI

[dfbowers]

Hi Don, what is your stock coil on your IDX? Is it the 10" DD?


If so, and you have both coils available, is it possible to do a coil swap comparison on the same afternoon..??

If the small concentric is better than the larger DD I would make it my next coil project - If I could get a shell !!

S

I have 5 coils to experiment with. a 9" DD, 10"DD, 7.5" concentric (all home built) plus a BM600 and 9.5" off of my XLT.

I took my 7.5" concentric hunting today, and once I got away from all power sources, I could run the IDX sensitivity at max and the coil was rock stable. Not so with my home built DD coils as I had to drop the sensitivity a bit for them to run quiet. Maybe that demonstrates my ability to build DD coils (or lack thereof).

I need to do a comparison run with both of my stock coils.

Don

[dfbowers]

Mefisto,

Nice work.. How did you shield your coils?

Don

[Koala]

Hi just a few quick question. Does the PCB have to be shielded and is it best to use a metal box. Do you have to be careful of ground loops. The PCB is the one by silverdog.

[Daxxin]

Hi just a few quick question. Does the PCB have to be shielded and is it best to use a metal box. Do you have to be careful of ground loops. The PCB is the one by silverdog.

I think that the working frequency is very low so not necessary the shields around the pcb ..anyway you can use the metal box that will give only small benefits against rf interferences.

[Davor]

Exactly. You don't have to stick with metal boxes, and even if you do - you still have to take care about the common ground point, and avoid the ground loops. A safe bet is to pronounce the cable connector ground the common point, and take care that there are no loops.

[golfnut]

Hi just a few quick question. Does the PCB have to be shielded and is it best to use a metal box. Do you have to be careful of ground loops. The PCB is the one by silverdog.

Do you have to be careful of ground loops?

Ive not tried to avoid them and got away with it.



Does the PCB have to be shielded?

If your away from electrical noise then its probably not required.

Although, I DO use a metal box for mine - Habit as RF background

Most of the opamps on these dont see above a few MHz, So Tv, Cell, FM radio, Taxis, police, hams etc are not a big issue.

Your most likely to have issues with the floating wires to your Geb and Disc pots - These have lots of Tx signal all over them and you can port this into your board at an unwanted place if unlucky.

I like pots mounted on the PCB edge - removing the threat of unwanted effects. Plus you cant wire them backwards which we all do on here!

Take great care in what you think is ground on IDX as its effective -4v rail is the Battery 0v. Odd isnt it. Does work though.



S

[Koala]

Your most likely to have issues with the floating wires to your Geb and Disc pots - These have lots of Tx signal all over them and you can port this into your board at an unwanted place if unlucky.

S

what is the best way to connect the pots. I have made twisted cables would it be better if they were shielded?

[Davor]

It is all the same, as long as they are not connected to each other by some short-cut. As long as you keep the star configuration you are golden.

[golfnut]

what is the best way to connect the pots. I have made twisted cables would it be better if they were shielded?

Twisting all three is a good solution. IDx is less prone to oscillation here.

Some receivers use two op amps in series for the Geb or Disc gating driver and have a 360deg phase difference between in and out with massive gain - these tend to oscillate - you can see this with a scope - you can get multiple decaying Gates of the mixer / det.

S

[onuba]

circuit board medidas

circuit board medidas en cm.. vdi.y idx pro someone can tell me

[konan]

Hello,

I made idx pro without display and its performance was pure. 1€ coin detect on about 15cm in the air, I made coil as founder give data for it (RX 35,6 mh, 92ohms and TX 0,587 mh, 1,8ohms) TX operate at 6,5 khz. I really don know what is wrong, pinpoint work perfect with them I can detect 1€ at 28 cm so I think that coil is good set. What can be reason for that pure performance ? Any sugestion?

I make from this pcb, from attachment

[Davor]

Don't know what your problem is - daj po naški.

[konan]

This is PCB :

[eduardo1979]

Hello,

I made idx pro without display and its performance was pure. 1€ coin detect on about 15cm in the air, I made coil as founder give data for it (RX 35,6 mh, 92ohms and TX 0,587 mh, 1,8ohms) TX operate at 6,5 khz. I really don know what is wrong, pinpoint work perfect with them I can detect 1€ at 28 cm so I think that coil is good set. What can be reason for that pure performance ? Any sugestion?

I make from this pcb, from attachment

If the cancellation of the coils is good, then you have to change the LF347 and U4 (LM393). You have to get some IC with more gain. The rejection of the ferrite and iron as they are?. Many factors can influence. The PCB is not very clean. Try what I said and tell us what happened. Regards.

[konan]

The coil is DD, when I override coils I get _____________________ on oscilloscope on RX coil. The rejection of iron is not good. I will clean my pcb. I will inform you about.