Printed spiral coil

[giuhalftrack]

good mornig everybody

Do you know the printed spiral coil in Tesoro PI detectors ?

I want know if the same can apply to a monocoil of BFO detector.

I'm asking this because I came across an old magazine that give instruction to build a coil like this (square) from a PCB...

I've study phisics long time ago and don't remember so much can you explain the advantages of this method.

Thank you

[Thomas]

There is no advantage to it, or we all would be doing it. I heard that there is an advantage with fractal cell phone antennas, but I don't know much about that.

[6666]

Is it possible that you can scan the old article and post here please ?

[Thomas]

I don't know who you were directing you question to, but here is what I think he is talking about. http://makezine.com/2014/03/27/quick...onductive-ink/

[sinclairuser]

this subject has been done to death before, do a search and you will find lots of reasons why its a bad idea.

[6666]

Sorry Thomas the question about the old article was directed at giuhalftrack
interesting link that you posted, thanks.

[giuhalftrack]

Sorry Thomas the question about the old article was directed at giuhalftrack
interesting link that you posted, thanks.

ok, as soon as i can i give you links (all bfo '60 '70 projects) or post the article

@Thomas
your link is very interesting, probabli this method of test have advantages beacause you can test a "real pcb" prototipe, I want it

[giuhalftrack]

ok this is the link, look at page 35 of .pdf

www.introni.it/pdf/Radio%20Elettronica%201976_03.pdf

if you are into old design of unstable and useless BFO this magazines contains lot of that:

www.introni.it/ (menu at left hit "vecchie riviste" - old magazines)

other two interesting links:

www.introni.it/pdf/Fare_30_59.pdf
american WWII metal detector schematics

www.introni.it/pdf/Sistema%20Pratico%201969_10.pdf
bfo with quartz reference

unfortunately they are all in Italian but i think is not a problem for schematics, if you have some trouble contact me in PM i provide some help in spare time.

[Thomas]

A gold mine, the Bob Pease Lab Notes are great. thanks for the links.

[6666]

Thank you giuhalftrack