Bounty Hunter Outlaw TR/BFO

A general theory discussion might be in order. Those coils are part of the detector's internal oscillator circuit in both the receiver and transmitter and an open circuit will cause a tone because the tuned circuit is simply missing a component. In both cases, they do double duty as an antenna. The power in a transmitter coil is very high compared to the receiver and that's why the single coil would be the TX coil. The receiver needs to have a very large sensitivity to its circuitry so more surface area and more windings normally result. It's designed in and internal components inside your detector are set to optimize tuning.

When an open circuit occurs, that will throw one or both into a tailspin and the rest of the detector sees the de-tuning as a target which cause the beep.

The 5 to 7 ohms you are reading might just be a coil itself rather than a short circuit. Thus, an open coil condition may exist on the other coils. The receiver coils are probably wound and wired in a position that gives an out of phase reception of the return field. This is how a Double D coil is wound and how it compensates for 70-80% of ground imbalance issues. It's not perfect but it does compensate.

What you now have to look for is any indication of which wire is open between your coil and your connector. Most certainly one is judging by what you are seeing at the pins. I suggest that you carefully peel back some of the black insulation from the cable and pick apart the shielding to see all of the wires. The weakest point in the circuit is where the wire goes into the coil and the next weakest is near the connector. Pay attention to both areas and use a pin to carefully prick into each wire to read it from the coil side to the connector. Some of the wires are going to be shorted together because of the coil receiver windings so be prepared to diagram everything as you take your readings.

Like I said, I wish I was there. It's a lot easier to point and show you than to theorize this stuff and make guesses. Frustrating, eh?

Posted on: June 07, 2011, 05:07:33 AM

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		Quote:			Posted by Big-Al
	I do not see a conductor used for a ground.

The Faraday shields that are wired to the connector are the ground leads. The coils are not normally grounded when a Faraday shield is used.

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The Faraday shields that are wired to the connector are the ground leads. The coils are not normally grounded when a Faraday shield is used.



He only has three wires.   Two plus shield.

Are you saying the Two are providing the TX and RX signal.   The Inductive Diverance between the two ?   That would not a be True TR!

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That was my first suggestion.   Check out the Connector end.

Got to admit!   It's a strange set up for sure.

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Well Gentlemen, the dissection has begun.

A 2 inch section of cable on the coil end has been opened up, revealing the following (SEE pHOTOS)

1) The cable has two center conductors, each with it's own individual shield. The two center conductors and shield are then covered by a main cable shield.

2) on the connector end and coil end, all the shields are connected together

3) There does not seem to be any corrosion other than some yellow flux on the shield attached to the coil. The cable has a thick jacket and looks in good shape.

How do you suggest that I test this cable? I would assume that I should sever it and test for shorts / open on the cable / coils

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Here's a circuit diagram of a simple BFO Detector with a Faraday shielded coil.

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, the design of the coil is a Faraday type.

Maybe this would be useful..

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