IDX-PRO+VDI

[golfnut]

"golfnut: Soe how do You set your ground balance without all metal channel now? Earlier i tried too to cut all metal channel while using a discrimination by a switch. but i haven`t noticed any differents."

There are 3 ch on IDX

PP,
Disc
GEB

I cut the PP out.

Geb as normal

S

[golfnut]

Ive had a chance to use this idx with 20V Tx.

Although deeper, I found the machine quieter and not so responsive on a real site containing a reasonable qty of iron.

It did work and pulled a small coin and a tiny bronze button and a cloak clasp from a small heavily worked area.


The downside to having more Tx is the Iron returns get significantly louder and longer - So the recovery time after an iron target is a little longer.

The impact to the user in this iron rich site is the swing speed needs to come down to allow reovery after every chunk of nail etc.



If you want to go deeper and have a quiet area with little iron this is a valid mod. If you are meticulous winkler or you have a concentric - this is a valid mod.

If you have a 10" + DD and want to crack on, this works fine without the iron infestation. My lawn I get upwards of 10 iron hits in a full swing!!!

I get between 1 to 1 1/2" extra (on testbed) using 20V Tx rather than 8V.


I may add a flip switch to toggle Tx power when i know the Iron content of a site.


Im looking at a pair of precision 1/2 wave rectifiers to cut off the large negative signals from Iron - in attempt to assess if the recovery speed is linked to large -ve traversals from Fe signals saturating the opamps in filter chain.

If true I should be able to keep the high Tx power and retain a higher sweep rate as we only use the positive going half for target Id anyway there should not be too much detriment to normal targets.

S

[reiv]

As always there is some plus and minus of any mod. I will try this too.
To disconect pp channel is it necessary delete those R3 and R5 resistors, it can`t be done deleting only C16 ? I`m asking because i want to use double switch of chosing all metal/discrimiantion mode, and he can also at the same time cut of C16 when you are using discrimination mode. But in all metal channell PP will works too. What do You think?

[golfnut]

As always there is some plus and minus of any mod. I will try this too.

The man good effect was raising the Tx rail.


To disconect pp channel is it necessary delete those R3 and R5 resistors, it can`t be done deleting only C16 ?




I dont get much advantage removing PP - it was there, I dont use it so I took it out.

A small amout of Rx signal was being consumed needlessly, as preamp signal was being shared into 3 loads - now 2. A small amount of noise is added by PP circuit when Disc mode.

The PP circuit is no longer clocked/gated, consumes no Rx signal, contributes no noise.





I`m asking because i want to use double switch of chosing all metal/discrimiantion mode, and he can also at the same time cut of C16 when you are using discrimination mode.

But in all metal channell PP will works too. What do You think?


I think you believe there is an ALL Metal Channel - there isnt.

There is Geb, Disc and PP


In normal Disc use all there CH are on. The PP channel is backed off a little and contributed almost nothing.

In PP mode the Geb and Disc outputs are isolated using the cmos switch - So in PP there is only PP running.


I would leave all the same just try the supply mod to Tx cct.

S

[ashefr10]

Hi, after having wired and boxed I can no longer adjust to ground effect.
Before rewire everything I could fine tune my ground effect with ferrite now when I want to adjust the knob 22K it nothing happens. Still it beep whatsoever to the max knob, middle or mini.

[reiv]

Ok I tried this. For me it is total unmisunderstanding. Sensitivity for small object is more than worst, for example a 15mm coin at 25cm in air gives only a humb...,on original tx voltage clear signal up to 32cm. Can`t see any "extra deep" in air, maybe in soil it will go deeper. But where is the point when You get inch or two and maybe find any deeper signal, bu You will miss thousends of small signals like thiny silvers..
And I really don`t know how do You set up your ground balance now in terrain. Normal procedure is to switch to pp, pump the coil etc... but with those cuts there will by no reaction to the ground, and adjusting ground balance in dscr. mode i think is not soe precise.

[reiv]

Hi, after having wired and boxed I can no longer adjust to ground effect.
Before rewire everything I could fine tune my ground effect with ferrite now when I want to adjust the knob 22K it nothing happens. Still it beep whatsoever to the max knob, middle or mini.

Because You cut the pp

[ashefr10]

to adjust my ground effect I use a ferrite bar, I put any metal and I it varied the adjustable 22 k, but it has no influence. in my case the pp is connected to a push button .it is so inactive as long as I do not support.

[golfnut]

Is it an easy job to remove from box and retest?

Are your wires to pots short as possible and twisted.

Be aware that the Battey -Ve is not the ground on these. The copper around the edge of the pcb is at +4v wrt the battery -ve terminal.


Your right PP is not Geb, Riev thinks it is.

S

[ashefr10]

everything is ok now. I reversed the pine TX. thanks

[reiv]

Your right PP is not Geb, Riev thinks it is.

S

Man You don`t understand me at all. I know where are all channels in circut

I asked You twice about something else with no answer. How do You want to set up properly your Ground Balance potentiometer now in the field/terrain without working channell PP (call as you want) ?? Because we all IDX users adjusting it like this: switch to pp mode,turn the treshold to min heard, pump the coil up and down, and adjust the GEB pot. to get the same voice pumping it up and down.. and as You see without PP it is imposible.

[golfnut]

Your right, I dont get what your on about.

"golfnut: Soe how do You set your ground balance without all metal channel now? Earlier i tried too to cut all metal channel while using a discrimination by a switch. but i haven`t noticed any differents."

This dont mean jack to me, sorry.


The top Ch in the drawing does get all metals - its function is for Pin Pointing.

The Disc Ch with pot rotated to one extreme is the ALL Metal mode on this kit.


to tune up - In Disc mode, Turn Disc pot to all metal, lower the threshold for detect on Sens pot, pump now will sound if Geb not set to average out the ground return. Or another way rest tip of coil on ground and adjust geb for minimum chatter, again have threshold for detect low so you hear the ever smaller chatter.

PP ch is not really adding anything in normal use, as its gain is lower - the main contribution is the other 2 ch's. Which I call disc and geb.


when u req PP mode you flip the switch and raise the pot so the PP CH becomes live, - in this state, disc and geb ch outputs are isolated.

You wouldnt search in pinpoint mode for all metal as its filter is wide noisey and slow.


"Because we all IDX users adjusting it like this: switch to pp mode,turn the treshold to min heard, pump the coil up and down, and adjust the GEB pot. to get the same voice pumping it up and down.. and as You see without PP it is imposible."

I dont. Im not saying Im right either. My machine ground balances really well and No PP CH. Like any other 2 CH machine e.g. golden sabre.

S

[reiv]

Now it is clear

Your right, I dont get what your on about.

"golfnut: Soe how do You set your ground balance without all metal channel now? Earlier i tried too to cut all metal channel while using a discrimination by a switch. but i haven`t noticed any differents."

This dont mean jack to me, sorry.

Here i just wanted to say that also tried to cut off PP while using DSCR. I put switch here:


But i can`t saw any difference, less noise or something, just it.

Your method to set up GB is new for me and for sure will try it outdoor. Just i`m not sure if i will be able to here something, now when turn tresh. and sens. to full in disc mode is silent in speaker, but maybe pumping at the ground it apears some chatter.

On top of that don`t You noticed less sensitivity for small object with higher Tx voltage?

[golfnut]

Now it is clear


Here i just wanted to say that also tried to cut off PP while using DSCR. I put switch here:


But i can`t saw any difference, less noise or something, just it.

I didnt observe any tangible difference either - but I never tried to measure it either.


Your method to set up GB is new for me and for sure will try it outdoor. Just i`m not sure if i will be able to here something, now when turn tresh. and sens. to full in disc mode is silent in speaker, but maybe pumping at the ground it apears some chatter.

Yes give it a try ground balancing really works.



On top of that don`t You noticed less sensitivity for small object with higher Tx voltage?

Not observed that, found some tiny lead and bronze with 30Vpp on Tx coil.


S

[ashefr10]

hello, having finished my idx, here some photographs of my detector. it is thus the initial version without the multi mode tons and without the bill-poster and with a head D 27 CM house doubles.