Aquasound

[Altair]

Altair, how is your coil build coming along?

I have done some more experiments.

First , I cannot get the aquasound Hartley oscillator to work at all. I have the correct inductance of the tx coil, but it won't oscillate. I must understand why.

Secondly, the same coil with the Hartley oscillator scheme from the Fisher 1210/1212x is running from the start, and working very good.

For a better oscillator, have a look at the Fisher 1260x.

dbanner,
concerning coil, Im busy now, I hope to make some progress next days.
I have saw Fisher 1260x oscillator, I think could be a good alternative.
What are inductances, resistances and caps of your Aquasound coil?

[dbanner]

Altair, I made a coil 8 inches, with 4inch for feedback. 0.4mm wire 40-10-10-40. I tried with 10nF cap and with other cap values.
Does not oscillate with aquasound oscillator.

Same coil is working very good from start with Fisher oscillator both 1212x and 1260x. I tried both and they work very good. Peak to peak voltage is measured 36v~

[dbanner]

I must figure out why coil doesn't work with aquasound oscillator circuit. I checked and rechecked my circuit. But it won't work.
However the simulation works. Waiting to see if you have better luck.

So l don't know what could be wrong. I double checked everything.

[Altair]

It could be due to not enough mutual inductance value.

[Altair]

Altair, I made a coil 8 inches, with 4inch for feedback. 0.4mm wire 40-10-10-40. I tried with 10nF cap and with other cap values.
Does not oscillate with aquasound oscillator.

Same coil is working very good from start with Fisher oscillator both 1212x and 1260x. I tried both and they work very good. Peak to peak voltage is measured 36v~

I like the 1260x oscillator.
Simulation give more voltage on coil and seems me it have a better stability.

[dbanner]

I like the 1260x oscillator.
Simulation give more voltage on coil and seems me it have a better stability.

I made the 1260x tx circuit and tried it with my coil.

It works very good.

1N60 diode on your last Sprint layout needs rotation 180 degrees.

[Altair]

...

1N60 diode on your last Sprint layout needs rotation 180 degrees.

You right!
Here the correction:

[dbanner]

The coil plugs.

https://projectpoint.in/index.php?route=product/product&product_id=501711119279

[dbanner]

Underwater coil plugs.

https://www.amazon.com/Waterproof-Connector-2Screw-Voltage-Bulkhead/dp/B07BK35YZF

[dbanner]

Nautilus coils.... expensive!

http://www.relichuntersupply.com/NautilusDetectors.html

[Altair]

dbanner,
I have doing a rapid test with my TX coil, .... it oscillate with Aquasound circuit from first start!
Respect original schematic there are the following differences:
- no Buck coils connected
- BC327 instead of 2N2907
- two 47K resistors instead of 50K, 51K ones
- power supply: 10V at 100 ohm resistor

Results:
- frequency: 17.748 KHz
- output p-p voltage: 26V

Coil is connected as indicated in my previous post #54, with exclusion of bucks.

[dbanner]

dbanner,I have doing a rapid test with my TX coil, .... it oscillate with Aquasound circuit from first start!Respect original schematic there are the following differences:- no Buck coils connected- BC327 instead of 2N2907- two 47K resistors instead of 50K, 51K ones- power supply: 10V at 100 ohm resistorResults:- frequency: 17.748 KHz- output p-p voltage: 26V Coil is connected as indicated in my previous post #54, with exclusion of bucks.

Great! So it works.I have several questions.First, what inductance/ number of turns/ coil diameter did you use.Secondly, what is the value of the tuning capacitor you used.I did not put 50k resistor from collector to other end of coil( I suppose this is for simulation of the two 100k potentiometers) when I tested my coil. I wonder if this is why my circuit don't oscillate.

[dbanner]

PCB is gigantic ridiculous large Godzilla. I don't have big copper board for this monster.
I must try to make layout smaller.

[Altair]

Great! So it works.I have several questions.First, what inductance/ number of turns/ coil diameter did you use.Secondly, what is the value of the tuning capacitor you used.I did not put 50k resistor from collector to other end of coil( I suppose this is for simulation of the two 100k potentiometers) when I tested my coil. I wonder if this is why my circuit don't oscillate.

51 + 51 turns on 228mm diameter with 0.5mm wire
Measured resistance: 3.6 + 3.6 Ohm
Measured inductance: about 1500 + 1500 uH
Capacitor: 10nF

[Altair]

...
Results:
- frequency: 17.748 KHz
- output p-p voltage: 26V
...

Really, p-p voltage was not measured across the whole coil (at resonant cap terminals), if you do it voltage is about 52V!