IDX-PRO+VDI

[ampirate]

What I dont understand is that I only get a CHIRP (with a COIN or Target) - I never get a continuous Squelch - no matter how I adjust the settings.

[Koala]

I finished my IDX PRO from Silverdog last week. I just tested it with my 27cm D-coil yesterday.
But, I still only get a range of about 3-inches. Same results as my home-etched Board.
I assume that this is a Coil problem then.

I followed the instructions as close as I could. But, I do not have an InductanceMeter.

Does anybody have a clear Windings-# and Rx and TX individual Circumferences for 0.2mm and 0.7mm Wire for a 27cm Coil ?

The Instructions always specify the total Diameter of 27cm for example - which varies by opinion.

Use the data on the first page and the shape of the DD form the TGSL thread works very well

None sharp sound sound like a voltage fault I get that when the batteries are running low. Try in PP mode see if its the same.

Also if you coil is too far out of spec you will get a broken sound in disc mode but okay in pp mode(all metal)

[ampirate]

Use the data on the first page and the shape of the DD form the TGSL thread works very well

None sharp sound sound like a voltage fault I get that when the batteries are running low. Try in PP mode see if its the same.

Also if you coil is too far out of spec you will get a broken sound in disc mode but okay in pp mode(all metal)

Aah Thanks ! - that is helpful...
If I hold the PP mode - then I can get a solid whine.
Else, Targets only give the 'broken sound' - Chirps ...
So, its the Coil.

I do have an Oscili/Datascope - so I should be able to use this to adjust the Coils properly - right ?

[golfnut]

If you dont have a scope, it can be difficult

Dont use the small black sounder from the kit as they are not very good.

use small speaker or headphones and it may sound ok.


What range do you get in PP - still 3"

[Koala]

If I hold the PP mode - then I can get a solid whine.

Should go quite if you turn the threshold down does it?
PP mode only works if the is a very fain hum not a loud buzz

[ampirate]

In PP mode - the Range is more like 2".

On the Oscilliscope, I am looking for:
TX = 6500Hz ,
Rx = 5000Hz ,
correct ?

But my TX Coil on the Oscilliscope reads at 3KHz at about 1.5V P2P.
So, this is too many winds or too few winds on the TX Coil ?
- Seems far off to me ...

I add 1 winding from 35turns to 36turnson TX coil ,
now gives me 10KHz on tx coil.

[ampirate]

No, I still get 10KHz with either 34 or 35 or 36 Windings on TX Coil.

[ampirate]

If this is true :

> This works very well with my unmodified setup. Touch under 40cm on my setup same for iron clad and copper 2p.
> Very reliable signal to 37 to an occasional beep if you get the speed and directly over the center at 40cm. Not as deep in real ground.
> 27DD TX wire from 0.70 to 35 laps
> 27DD RX wire from 0.15 to 270 laps

Then, how do I convert 27DD RX Coil of 0.15 Wire of 270 Turns ,
to a 27DD RX Coil of 0.20 Wire of Turns = ???

[ampirate]

Okay,

For RX Coil, if I use 269 Turns for 0.2mm Wire ,
then following the 270 Turns for 0.15mm Wire.
I calculate comes to 41mH.

I added 15 Turns to my 255 Turn 27DD RX Coil of 0.2mm Wire - to give me 270 Turns.
(My mistake was to use only 255 Turns on my RX coil)

I get an improvement for coin Range of:
- Squeal at 6inch,
- Chirp at 8inch now.
Better, but still not great though.

[Koala]

In PP mode - the Range is more like 2".

On the Oscilliscope, I am looking for:
TX = 6500Hz ,
Rx = 5000Hz ,
correct ?

But my TX Coil on the Oscilliscope reads at 3KHz at about 1.5V P2P.
So, this is too many winds or too few winds on the TX Coil ?
- Seems far off to me ...

I add 1 winding from 35turns to 36turnson TX coil ,
now gives me 10KHz on tx coil.

No the Rx will always be the same as the Tx except it will be out of phase

[Koala]

easier to adjust the frequency by changing the capacitors

If you gave a good winding of 35t .7mm then then it will be close to correct frequency with a 1 mF capacitor

You then have to adjust the Rx capacitor trial an error for best distance and still disc and ground balance.

Sound like you are getting close good detector worth sorting out

[ampirate]

No the Rx will always be the same as the Tx except it will be out of phase

Ok, but my Scope does not have dual channel to see the Phase comparson.

You then have to adjust the Rx capacitor trial an error for best distance and still disc and ground balance.

Are you talking about the External 33nf Cap ?

[golfnut]

In PP mode - the Range is more like 2".

On the Oscilliscope, I am looking for:
TX = 6500Hz ,
Rx = 5000Hz ,
correct ?

But my TX Coil on the Oscilliscope reads at 3KHz at about 1.5V P2P.
So, this is too many winds or too few winds on the TX Coil ?
- Seems far off to me ...

I add 1 winding from 35turns to 36turnson TX coil ,
now gives me 10KHz on tx coil.

As Koala said the Rx signal is a leaked quantity of the Tx signal - the frequency is the same.

The Rx tuned cct is tuned off resonance away from the Tx .

Adding 1 turn will never make freq jump from 3k to 10k you made an error here some how..

If you got a solid Tx volts of 15vpp but your nervous the Tx is high for you, add 0.47uF across your Tx cap and should jump down closer, give that a try.

[golfnut]

try ferrite, when you can tune it out with geb control - your phasing has to be correct.

[Koala]

Are you talking about the External 33nf Cap ?

Yes

Small difference in capacitor value here can make a big difference to distance.