fisher f2 32 dd coil

[kuzen]

hi friends,ı have fisher f2 detector.ı want maked for detector 32cm dd coil,fisher f2 coil parametres do not know,,tx coil R ohm and mh.,,rx coil R ohm and mh ? and friends Does the coil have a schematic? thnx best regards

[Skippy]

Receive coil (pins 1 and 2) is 2.4 mH , R = 5 Ohms.
Transmit coil (pins 3 and 4) is 2.4 mH in parallel with (220 nF + 22nF), resonant at 6.6 KHz. DC resistance of coil is 8 Ohms.
An alternative TX would be 220nF and 2.65 mH, though I haven't tried it.
Capacitors: the 220 nF would be best if polypropylene, though polyester/mylar would be OK. The 22 nF will be fine in polyester (and could be 20 nF)

[kuzen]

thnx friends skippy,

you Say tx mh. and rx mh the same ? Are the capacitors in the coil ? can you send a photographs for fisher f2 coil?

thnx best regards

[kt315]

http://www.metdet.ru/Sensor_F2.htm

[Skippy]

Ah...I forgot to say, Pin 5 is a screen/shield, though I don't know what shielding arrangements are used inside the coil (DD or concentric)

The RX coil resistance is not critical, I'm sure R = 10 Ohms would make no real difference.

The TX caps are internal to the coil, regular wire-leaded ones.
And in case you were wondering, the F2 / F4 have an additional 47 nF capacitor inside the control box, connected across the TX coil. This extra capacitance drops the operating freq down from the original (Bounty Hunter) 6.6 KHz to 6 KHz (5.9 maybe).

Here's some online pics inside the small 4.5" 'nugget' concentric coil:
http://www.whiteriverprep.com/vintag...ch/bhtech.html

[Skippy]

Update: I forgot, there's two different connectors used on the F2, the 240 degrees DIN, and the "CB-radio mic" screw-on.

For the earlier DIN version, pinouts are:

Transmit coil: Cold end = Pin 2, hot end = Pin 5.

Receive coil: Cold end = Pin 1, hot end = Pin 4.

Shield is Pin 3, and is not connected to the other wires.

I may have the other connector pin numbers wrong, I can't remember where I got the info. Hopefully you can work it out using your own coil as a guide.

[kt315]

http://www.treasurenet.com/forums/tr...connector.html
same like BH

[Skippy]

Yeah, that's correct, they used BH coils on early F2's, then changed to the screw-on connector. I prefer the DIN connector myself, the quality of the screw-on connectors is terrible, you don't get much for 50 cents.