ARADO 120 SCH& PCB

[Carl-NC]

I didn't know that had so many models. I've only heard of the 120(B), which I have one.

[daluka]

History of Arado since 1975.

[ivconic]

In 1987 when I was 21, I went to London and bought my first detector.
That was the Arado 120 you are talking about here.
I used it until 1991/2 when I sold it and bought a White's Eagle IIc.
Ah... the good old days! Brings back so many memories!

[kt315]

daluka

Geotech Metal Detectors - Patents (geotech1.com)

[daluka]

Patent 4096432, Arado Electronics, Paul Anthony Spencer

[GeoMax]

Just in case if someone is interested....

I see a Classic Arado 120B with meter discriminating metal detector currently offered on eBay UK.
Here is the link https://www.ebay.co.uk/itm/126670959733?

[Malospelos]

Good morning colleagues, yesterday I received an original Arado 120B, after maintenance, I have brought it back to life, everything works, it came with an original coil, the only thing is what depth should I put?
It has an 8" coil and accepts a 1 euro coin at approximately 25 cm.
I would like to know if making a coil could increase or improve the performance. I have heard that it was very deep, but it doesn't seem that way to me, I don't know if it should be tuned, part of the board comes with Epoxy so you can't see the components.

I also wanted to ask if it is possible to set a Ground Balance.

[Toros]

Andreas has not been here for a long time.

Apparently I'll have to redraw the board myself.

[aft_72005]

Can you post the files in "Express pcb" format. In PDF format I can't edit the board trace.

Andreas has not been here for a long time.

[Toros]

Hi all
All you have heard for "Myth " arado120.
I make this two years ago, with fine results and new design PCB . This machine has voice for all metals and Ameter for discrimination. With this method, we can heard a detection target and with eyes, we can see dicrimination
Here is sch diagram without errors and full analytical PCB (101,60mm X 81,28mm) without errors too. The next post i publish infos for (how make Tx-Rx coil). My machine work with O-O coils 20cm diametre and detect a euro 36cm distance on air, a box 20cm X 20CM 95cm distance on air . Maybe with D-D coil is better... we want try for this. In practice never i use, only inside laboratory. Easy make PCB, with easy coils and difficult calibration "null".
I don't answer questions, why I believe this is very analytical, only you want make PCB.. put parts and finish
In next post I will present photo's, Method of calculations coilsand method calibration "null"
I wish good success
best regards
Andreas

Can you post the files in "Express pcb" format. In PDF format I can't edit the board trace.

[daluka]

Like this



but controlled by DC voltage, not your fingers.

https://www.usefulcomponents.com/mai...iable_cap.html

Variable Capacitor

[Pete61]

What is it?

Like this



but controlled by DC voltage, not your fingers.

https://www.usefulcomponents.com/mai...iable_cap.html

[daluka]

This quote from Andreas #30
you must build a electronic-cap

HAS ANYBODY A SCHEMATIC FOR ELECTRONIC-CAP PLS?

What is it?

[nimalgr]

HAS ANYBODY A SCHEMATIC FOR ELECTRONIC-CAP PLS?

[Pete61]

Pete61 I CONNECT ONLY THE TX COIL ON PCB AND PARALLEL CONNECT THE FMETER.....I PUT 4.650 THE FREQ.......AND AT TX TURNS PUT 45 TURNS PLUS AT RX COIL. DO YOU KNOW HOW I 'II SEE THE FREQUENCY OF RX COIL?THANKS

From what Ive read, you connect the Rx coil and its capacitor to the TX position on the pcb to read its frequency. Then instead of adding or taking away Rx coil loops, you change the vari cap to get the right freq and then read the vari cap's value to choose a correct fixed cap for C17 or C18, which ever one it is.

I havent built one, so Im just forming an opinion based on what Ive read in these forums.


This quote from Andreas #32

C17,C18 you don't put now your PCB. After resonate Tx coil, you know if C17,C18 are right or not

#30

My method is simple for your all. After you build PCB , you must build a electronic-cap with range 50-300n. With this electronic-cap we can make a fine tune Rx coil.If you find this parts (example 101,5n) then replace with normal capacitor/capacitors and only difficult point is a "null" Tx/Rx. With this method we don't need variable capacitor between Tx/Rx
best regards