Dutch Metal Detektor with CD401

[Funfinder]

OK, that's it for now.

[kt315]

BFO again. i do not collect BFO schematics and you do not find them at the DVD-ROM with archive.
no deep sense in what does not have perspective.

[Teleno]

Translation:

Simple metal detector aroud a CD4011 conssiting of two oscillators.
The frequency of oscillator 1 is determined by the search coil (Zoek spoel).
Oscillator 2 is tuned with a 500p capacitor until a tone can be heard in the headphones.
Small metal parts next to the search coil will now cause a clearly audible change in tone
up to a distance of 30 - 120 cm depending on the composition and size of the object.
The Mg. socillator coil must be enclosed by a metallic screen.

[Funfinder]

thanks for the translation
120cm ??? WOW !!!

[ODM]

This same detector has been posted many times under many names. All BFOs using logic IC oscillators have about similar performance, 120cm is probably a realistic detection distance for a buried Tiger-tank made from wire grade copper...

Unless there is any particular interesting feature about it, it's much like posting the same PI/VLF detector over and over under a different name like some national clones seem to appear. Can you post all these old BFO schematics under a single thread? For a very good example, KT315 keeps a thread for his own schematic archive.
It is easier to read through an "archive" thread instead of many small cluttery threads that easily get lost in the forum. If you want to preserve these schematics I suggest you make them a single archive!

[homefire]

BFO still has it's uses. My First detector was a BFO from the back of a Rag Mag . You have NO Idea how long it took me to Con my mother into paying the $50.00 for it. Crusader it was called. Think it had a whole 6 transistors. Came in the mail and ten minutes later found a 1954 Silver Quarter not two feet from my front door. I was Screwed !!!!! Life would never be the same. Prospecting It could find me the Hidden Black Sands that at one time produced 1/2 oz from one spot. Never, Never Underestimate a BFO.

[Teleno]

BFO still has it's uses. My First detector was a BFO from the back of a Rag Mag . You have NO Idea how long it took me to Con my mother into paying the $50.00 for it. Crusader it was called. Think it had a whole 6 transistors. Came in the mail and ten minutes later found a 1954 Silver Quarter not two feet from my front door. I was Screwed !!!!! Life would never be the same. Prospecting It could find me the Hidden Black Sands that at one time produced 1/2 oz from one spot. Never, Never Underestimate a BFO.

Check this out: BFO ground balance - has this been done?

[Altra]

Another bfo variation for the collection. This one reads and outputs the phase shift.

From July 1978 Wireless World "Discriminative metal Detector". See page 43.


http://www.americanradiohistory.com/...ld-1978-07.pdf

[kt315]

take something from the lists and show up. if you would like to produce a noise so do that hard.

literatura nt wykrywaczy.pdf
literatura.pdf