IDX-PRO+VDI

[paku]

i have buy silverdog board yesterday arrived at my home
now i need parts of component for installation

[silverdog]

I did not read the whole thread so I can repeat. When I start idx'a I found a bug on the PCB from silverdog. It is short circuit X and Y signal:

[ATTACH]24871[/ATTACH]

Unfortunately this is true, the latest batch seems to have larger pads and have caused a short - I fixed mine easily with a craft knife, just sliced through the edge of the pad and lifted it , no more short
I will get some corrected pcbs made with smaller pads
I have put this boards in my bargain bin at just £1 each to clear - if you have a knife grab a bargain !

http://www.silverdog.co.uk/shop/index.php?route=product/product&path=37&product_id=123

[Davor]

You can always fine tune the null with a small piece of ferrite and a small chip cut off of a milk carton.

[golfnut]

Nulling,

If your Tx coil has 15V on it

and Your Preamp has 45dB gain

Preamp output is 100mV.


Is your Tx to Rx isolation, Null Job = 89dB ?

S

[golfnut]

i have make DD coil For TGSl
Can I Use It For IDX Pro Or i Need Make New Coil For IDX Pro

It is worth a try.

I suspect it will air test ok - in use, depending on soil type - you wont be able to ground balance it properly.


The reason it wont GEB properly is that the phase shifter affected by frequency - Change freq and the phasing slides.


So, the GEB will not 'average out the GND signal as it will be sampling or gating the GEB CH mixer/detector at the wrong place in time or 'Phase' - and you wont have enough control range to pull it to the correct phase or gating 'Time' wrt to Tx signal.


- I needed to alter my GEB pot to run IDX at higher frequency - Do a simple model in lt spice and pick a pot that gives you similar phase shift and control range at the higher frequency that the original pot gave at 6.5kHz.

Its a fairly easy tweak and works fine.



I dont know where the recurring wyths come from that your Tx has to be correct to 3 decimal places...



General..
I found I got better sens and usability with the Rx tank on Low side rather than the high side. Theres no good reason for that, just what I got at the time.


If you find it sounding off a lot - The Rx tank may too close in freq to the Tx freq.


A rough guide for delta in freq from Rx to Tx is about 75%
So Tx of 12kHz - - - Rx would be at 8kHz. This should give an easy to use machine with reasonable sens.


All open to discussion and years of relentless to'ing and fro'ing ...

S

[Davor]

It is basically the same thing. You know, or you can measure the inductances of your Tx and Rx coils so you can adjust respective capacitors to work properly.

[paku]

i have make DD coil For TGSl
Can I Use It For IDX Pro Or i Need Make New Coil For IDX Pro

[golfnut]

Can I replace mpsa13 with mpsa14 ?

PRO ..Yes you will get more punchy audio as more gain.

Con.. Worst case you could run into instability, and oscillation in or out of audio band.


Suspect it will be fine.

S

[golfnut]

How are the performance of IDX-PRO+VDI i.e depth range...
Fe and non Fe metal... And other.....

Low mineralised Europe soil, damp.
Disc set to reject Iron
10" homemade DD Tx at 11.6kHz .. Rx tank 8.5kHz
12.5mm diam lead ball target

4" loud punchy clear tone
5" for clear tone
6" no response


Silver disc 99% pure silver
15mm diam
6.5" weak tone - digable


DISC open to ALL metal

Same test conditions

4,5,6 inches clear loud tone

7" tone digable

8" partial tone - would not dig

9" no response


Silver coin at 6 1/2" slightly louder tone


S

[konan]

Can I replace mpsa13 with mpsa14 ?

[Schatztaucher]

You can find this information in the thread

[mahavir]

How are the performance of IDX-PRO+VDI i.e depth range...
Fe and non Fe metal... And other.....

[Schatztaucher]

my silverdog pcb was ok....but it was one of the first pcb´s....without the changes....

[pepe]

Mistake on silverdog's PCB

I did not read the whole thread so I can repeat. When I start idx'a I found a bug on the PCB from silverdog. It is short circuit X and Y signal:

[Schatztaucher]

http://www.youtube.com/watch?v=uaJNBRG0aQM

idx with lugatek