OLD BFO

[aft_72005]

Hello
This is a BFO circuit from an old German magazine.
Does anyone have the schematic? Or does anyone know the name of the magazine and the year it was published? It seems to be Elector magazine.

[Qiaozhi]

Unless someone has a copy of the magazine I doubt you will find this freely available.
It appears to be called "Digitaler BFO-Detektor" from a 1987 Elektor magazine.
Their website has a full archive of all their past magazine, but you need to be a subscriber to Elektor magazine to get access.

[aft_72005]

Unless someone has a copy of the magazine I doubt you will find this freely available.
It appears to be called "Digitaler BFO-Detektor" from a 1987 Elektor magazine.
Their website has a full archive of all their past magazine, but you need to be a subscriber to Elektor magazine to get access.

Hello Qiaozhi
Thank you for your attention. I have the files of the Elektor magazine in my home archive. I will look for it with your guidance.

[moodz]

It might be on about p183 ..of Andreas Gatowski, Schatzsuche mit Metalldetektoren – Technik, Selbstbau, Geländeeinsatz, Elektor-Verlag, 1990 (reprinted 1993, ISBN 3-921608-81-3)

[Qiaozhi]

It might be on about p183 ..of Andreas Gatowski, Schatzsuche mit Metalldetektoren – Technik, Selbstbau, Geländeeinsatz, Elektor-Verlag, 1990 (reprinted 1993, ISBN 3-921608-81-3)

I have a copy of that book. It's an Elektor publication.
Yes, you're correct. The images that aft_72005 posted are exactly the same as the ones from the book. The schematic is on page 184.

[GeoMax]

Hi aft_72005,

if you have the archive from KT315, check out the folder "Andreas Gatowski_Schatzsuche mit Metalldetektoren_1990" there is a complete scan of the book. Below is the BFO project.

[aft_72005]

Hi aft_72005,

if you have the archive from KT315, check out the folder "Andreas Gatowski_Schatzsuche mit Metalldetektoren_1990" there is a complete scan of the book.

Hi Geomax

Thank you .

[Aziz]

Hi all,

the book "Andreas Gatowski_Schatzsuche mit Metalldetektoren_1990" was my first book on metal detectors and I loved it.
I have built the BFO. It is a toy and can not be compared to a serious metal detector for field use of course.
It is better to build the PI detector published in Elrad or so in the 80' - 90'th. This worked much better.
Aziz

[Aziz]

Hi all,

BTW, here is the PI metal detector I have mentioned published in Elrad dated to 1985/9.
Link: https://www.mikrocontroller.net/atta...AD_1985-09.pdf

Don't waste your time with BFO's. They are not useable in the field.
Aziz

[kt315]

make Barracuda. it is very small compact board with ground compensation. you waste a time on a BFO without result.

[aft_72005]

make Barracuda. it is very small compact board with ground compensation. you waste a time on a BFO without result.

Hello KT315
Yes, I know that the BFO system is an old metal detector.
I also work on the long range system... Years ago, Esteban said in the Long Range Farm that the BFO could operate in long range conditions.
Years ago, Wireless World magazine published a BFO design that showed 4 LEDs that could detect very small frequency changes of a few hertz. I don't remember the year and month of that magazine now. Maybe it was the 80s.
That circuit without the coil shield behaved strangely and was also non-metal detecting.
I thought a lot and realized that maybe I had unknowingly built a long range at that time!!! Of course, I had built that circuit on a breadboard.. Now I can't find that article on the BFO digital metal detector in Wireless World magazine.
Now I'm interested in reviewing and researching BFO again for this reason.

Unfortunately, Esteban went blind and left the Long Range site... He was very active and wrote about long range systems in his time... Many people did not believe it. I myself did not believe in long range detectors until 2010, when I built a circuit that had been detected by long range detectors several times under certain conditions, and I realized that there was a phenomenon around very old metals.

[aft_72005]

Hi all,

BTW, here is the PI metal detector I have mentioned published in Elrad dated to 1985/9.
Link: https://www.mikrocontroller.net/atta...AD_1985-09.pdf

Don't waste your time with BFO's. They are not useable in the field.
Aziz

Hello.
Thank you for the schematic you provided.