Sandbanks

[Mr.Jaick]

You need to go to the Tech Forum.

there are so many threads
maybe i can find something relevant
or start new one for more complex questions
thanks

[Mr.Jaick]

dig all. this is first rule.

oh that one of course
but i don't want it for that
currently i'm working on felezjoo and wanted to find the best setting for gold
kinda calibrate the damn thing, any ideas?

[waltr]

As was stated in the 'find arrow' thread. Gold is very variable with detector's response.

The Alloy and size and shape and take part in how a detector responds to gold.

Therefore, Dig All.

The last Gold ring (14K with four diamonds) ID'ed as a small piece of Can Slaw.
A small gold locket (14K) id'ed in the Brass range (gun shells).

But since I was digging all I found them.

[Mr.Jaick]

As was stated in the 'find arrow' thread. Gold is very variable with detector's response.

The Alloy and size and shape and take part in how a detector responds to gold.

Therefore, Dig All.

The last Gold ring (14K with four diamonds) ID'ed as a small piece of Can Slaw.
A small gold locket (14K) id'ed in the Brass range (gun shells).

But since I was digging all I found them.

i'm a dig-all guy too
but i want that to test pi detectors
as you know often pi detectors doesn't detect gold so well including sandbanks
the last time i tried to detect a thin 14k gold ring with a 30cm (12in) coil i almost had to place the ring on the coil cover
to be able to detect the ring. ***\ Atrocious /***
hopefully they can detect a big chunk of gold at least...

[samir3]

its good send me the cercuit

[surfdetector]

its good send me the cercuit

The Sandbank project is here:
https://www.geotech1.com/cgi-bin/pag...anks/index.dat

[gerson]

Corected schematic

Hi Strujas. Could you make the PCP/PB diagram for this version of your sandbank schematic available here? I found the separate circuit you posted in the schematic very interesting. I would greatly appreciate it if you could publish it here, or send it to my email address: [email protected]

[GeoMax]

Hello Gerson,

Here is some information regarding the Sandbanks PI. The Sandbanks PI refers to the original circuit design that was published in Practical Wireless magazine in 1979. Later, someone made minor modifications to the power supply section and named the circuit "ProScan." Subsequently, another individual from Poland redrew the circuit using modern, readily available components, resulting in the "PI-Polones." While other names for this same detector do circulate online, they are all fundamentally based on that original Sandbanks PI from 1979.

[Orbit]

My opinion is that you do not change the pcb that is in the magazine from the link provided by Geo Max because a different layout can affect the stability of the device! It is only necessary to make a good transformer, nothing more!Sand detector original version, works best transformer can be easily made best use ferrite round transformer which raises voltage from oscillator 4011 to some 24 to 28v and then 7812 lowers it to 12v. Power supply ic is a total of 17v. I made about 5 or 6 pieces very stable in operation! The changes made by Strujas are my changes for quick reaction, I also used them in real search.Replace R31 with a 50k Potentiometer to be able to sample from 15us - 25us earlier I used a 32cm diameter coil and 17 turns of 0.45mm or 0.50mm copper wire the resistance of R31 would be somewhere around 17k if I remember correctly they would have sampled at 15us..Buy a ferrite core to fit on the original pcb, those transformers are somewhere around 1.5cm in size. wind two coils simultaneously and 100 rounds of thin wire 0.025mm or similar, when you have wound 100 rounds on those 100 rounds, wind another 8 rounds to 10, but only one wire and the transformer just need to be put and connected in place, sometimes you may need a capacitor on cd 4011 change to achieve if I remember some 32 or more khz for the transformer to deliver a stable 24v.

[scs-bg]

It is difficult to make a better pulse detector. From experience I know that at 220 hertz it works perfectly. There is only a problem in the temperature drift of the JFET transistor of the VSO.

[gerson]

Hello Gerson,

Here is some information regarding the Sandbanks PI. The Sandbanks PI refers to the original circuit design that was published in Practical Wireless magazine in 1979. Later, someone made minor modifications to the power supply section and named the circuit "ProScan." Subsequently, another individual from Poland redrew the circuit using modern, readily available components, resulting in the "PI-Polones." While other names for this same detector do circulate online, they are all fundamentally based on that original Sandbanks PI from 1979.

Thanks Geo for the information.

[gerson]

My opinion is that you do not change the pcb that is in the magazine from the link provided by Geo Max because a different layout can affect the stability of the device! It is only necessary to make a good transformer, nothing more!Sand detector original version, works best transformer can be easily made best use ferrite round transformer which raises voltage from oscillator 4011 to some 24 to 28v and then 7812 lowers it to 12v. Power supply ic is a total of 17v. I made about 5 or 6 pieces very stable in operation! The changes made by Strujas are my changes for quick reaction, I also used them in real search.Replace R31 with a 50k Potentiometer to be able to sample from 15us - 25us earlier I used a 32cm diameter coil and 17 turns of 0.45mm or 0.50mm copper wire the resistance of R31 would be somewhere around 17k if I remember correctly they would have sampled at 15us..Buy a ferrite core to fit on the original pcb, those transformers are somewhere around 1.5cm in size. wind two coils simultaneously and 100 rounds of thin wire 0.025mm or similar, when you have wound 100 rounds on those 100 rounds, wind another 8 rounds to 10, but only one wire and the transformer just need to be put and connected in place, sometimes you may need a capacitor on cd 4011 change to achieve if I remember some 32 or more khz for the transformer to deliver a stable 24v.

I also thank you, Orbita, for giving me more details about this project. I will try to reproduce it as you instructed.