Fisher F2/F4 coil

[Geo]

Hi.
Does anyone has details from the Fisher F2/F4 coil ???

Thanks

[WM6]

Hi.
Does anyone has details from the Fisher F2/F4 coil ???

Thanks

Also interesting.

Planning to open one for inspection but still "lack of time". Days are so short.

[Geo]

Also interesting.

Planning to open one for inspection but still "lack of time". Days are so short.

No need to open one!!!.
If you know the inductance then is OK for me.

[WM6]

No need to open one!!!.
If you know the inductance then is OK for me.

Geo, to measure inductance is not problem. Measured at two different frequencies (1kHz and 10kHz).
As you can see from data there is not only "inductance" in coil.
I do not know which is TX and which RX, without coil TX oscillator do not oscillate and I haven't such connector by hand to test oscillator with such inductance.
Maybe you know contact configuration?

[Geo]

WM6, thanks for info!.
I have not any info about it. I found some small coils 4" at very low price and i say to give at one a try as head of my lrl. I will open it to play with the tuning but i need small inductance. From 0.5 to 2 mH it is OK.

Regards

[Skippy]

The coil spec is the same as this one, apart from the receive coil resistance being a little different( 5 ohms instead of 8 ):http://www.geotech1.com/forums/showthread.php?t=17905

[Geo]

The coil spec is the same as this one, apart from the receive coil resistance being a little different( 5 ohms instead of 8 ):http://www.geotech1.com/forums/showthread.php?t=17905

Thank you

[WM6]

The coil spec is the same as this one, apart from the receive coil resistance being a little different( 5 ohms instead of 8 ):http://www.geotech1.com/forums/showthread.php?t=17905

Thanks Skippy. Then B* pins are TX, cause A* pins (windings) do not change inductance related to frequency. Capacitance is then added to B* windings.

[Dave J.]

The F2/4 coils are electrically the same series as the regular Bounty Hunter coils. Don't have the exact data in front of me at the moment, but both the transmitter and receiver windings are approx. 2.4 mH. The transmitter is parallel resonated with a .22 uF capacitor to resonate at about 6.7 kHz. Therefore at 10 kHz the transmitter reactance is capacitive whereas the receiver is still inductive.

To get good induction balance, the windings must be phased correctly. Sorry, don't have a connector pinout handy.

For playing around, BH searchcoils are a good deal because they're inexpensive and widely available. Building your own induction balance searchcoil and getting it right is a tough job that most experimenters are going to fail at. Better to buy the searchcoil ready-made and spend your time playing with electronics.

--Dave J.

[Geo]

The F2/4 coils are electrically the same series as the regular Bounty Hunter coils. Don't have the exact data in front of me at the moment, but both the transmitter and receiver windings are approx. 2.4 mH. The transmitter is parallel resonated with a .22 uF capacitor to resonate at about 6.7 kHz. Therefore at 10 kHz the transmitter reactance is capacitive whereas the receiver is still inductive.

To get good induction balance, the windings must be phased correctly. Sorry, don't have a connector pinout handy.

For playing around, BH searchcoils are a good deal because they're inexpensive and widely available. Building your own induction balance searchcoil and getting it right is a tough job that most experimenters are going to fail at. Better to buy the searchcoil ready-made and spend your time playing with electronics.

--Dave J.

Hi.
I am plan to buy it new and to play with electronics (with capacitors for better tuning)