NE555 VLF transmitter

[WM6]

Simple VLF transmitter with aerial coil wire antenna and changeable frequency can be build using wide available NE555. Not with ideal sine wave but usable.

Potentiometer should be, for more precise frequency selection, multi-turn one (if possible), but not required.

Antenna coil data: outer coil diameter >22cm, wire diameter 0.25mm, coil resistance >33 Ohm, number of turns approx 111, inductance about 5mH, wire length needed about 80meters.

PCB dimension 2.1" x 1.6".

[WM6]

Proposed circuit generate bursts of selected frequency.
This can be usable if we select frequency out of human audible range (say > 22kHz) which can be then on RX side demodulated to make bursts audible. We can lower C2 to 10uF.

[Fred]

Hi WM6,
May i ask what is the purpose of the circuit, (except scaring mosquitoes) ?

[WM6]

Originally Posted by Fred

Hi WM6,
May i ask what is the purpose of the circuit, (except scaring mosquitoes) ?

Hi Fred,

purpose of this circuit is, as previous stated, VLF transmitter (very important thing in some sort of electronic dowsing).

DO not be fooled by a weak signal, it is even too strong and need to be limited (limiter not included in circuit yet, but is very simple to apply one) for best sensing results.

You are free to use this circuit for scaring mosquitoes, if your mosquitoes warriors believe in electronic dowsing.

[morsuvari]

Originally Posted by WM6

tHi Fred,

purpose of this circuit is, as previous stated, VLF transmitter (very important thing in some sort of electronic dowsing).

DO not be fooled by a weak signal, it is even too strong and need to be limited (limiter not included in circuit yet, but is very simple to apply one) for best sensing results.

You are free to use this circuit for scaring mosquitoes, if your mosquitoes warriors believe in electronic dowsing.

Thanks WM6,it is very nice.
-morsuvari-

[Metaldude]

What is the VLF transmitter used for? (Forgive my primitive knowledge), that is, how is it used to find minerals?

[Dave J.]

Originally Posted by Metaldude

What is the VLF transmitter used for? (Forgive my primitive knowledge), that is, how is it used to find minerals?

Finds minerals through the use of lots of imagination.

Like a 5 year old kid fending off space invaders with a ray gun comprising his mother's keychain flashlight.

No matter where you go, there are no space invaders, and there are minerals. So it appears that both methods are effective.

--Dave J.

[J_Player]

Originally Posted by Fred

Hi WM6,
May i ask what is the purpose of the circuit, (except scaring mosquitoes) ?

Hi Fred,
Mosquitoes are not scared from VLF transmissions.
But if you want to use this circuit for mosquito scaring, you can make a modification to the output at the antenna coil.
By adding a single transistor and resistor plus a piezoelectric transducer, you can make audible sounds which follow the bursts that are being sent at the coil.
Of course, you want to choose sound frequencies that mosquitoes hate, so they will stay away.
This can be good for a dowser when he is treasure hunting, or for a non-dowser for when he is at a picnic lunch during mosquito season.
But be careful... do not adjust to frequencies that attract mosquitoes.

Of course, do not publish what kind of transistor or buzzer ... (spies are watching).


Best wishes,
J_P

[zixelll]

Originally Posted by WM6

Simple VLF transmitter with aerial coil wire antenna and changeable frequency can be build using wide available NE555. Not with ideal sine wave but usable.

Potentiometer should be, for more precise frequency selection, multi-turn one (if possible), but not required.

Antenna coil data: outer coil diameter >22cm, wire diameter 0.25mm, coil resistance >33 Ohm, number of turns approx 111, inductance about 5mH, wire length needed about 80meters.

PCB dimension 2.1" x 1.6".

Hi, after further explain for winding machine