Subassembly Pretest

To run a test on ihe device, follow these sieps:

1. Turn pots R5 to full counterclockwise (CCW), R4 trimpot to midrange, and SI to off (down position).

2. Connect a 10- to 25-watt, 500-ohm testing power resistor to the output leads. If you have a scope. it is suggested that you connect it to the drain of Ql.

3. Apply a 12-voll DC to the input leads, and turn Si on (to the up position). Adjust R5 full clockwise (CW) and note that the input cur­rent does not exceed 2.5 amps. Adjust trimpot R4 to limit this maximum value with R5 at full CW. Check for wave shapes as shown with R5 at full CW and CCW. Do not operate into the

test resistor for too long as the resistor may overheat.

4. Verify D4 LED lighting when S1 is energized.

Final Rssembly

To complete the assembly, follow these steps:

1. Cut a 10-inch piece of З’/мпсЬ OD schedule 40 PVC tubing for the enclosure (EN1). Rework the 3’/2-ineh plastic end caps by sim­ply poking two small holes for the output leads (CAPl). Cut out the eemer of cap CAP2 by placing it onto a suitable form and remove the center with an x-acto knife using the wall of the form lube as a guide.

2. Retest using a load resistor and verify all the controls before actually using the device. It is a good idea to attach suitable connection clips to the input leads tor battery terminals.

3. Connect the output leads to a suitable probe scheme and study the instructions section of these plans.

4. Place a high-voltage warning label on the enclosure (see Figure 24-7).


Your fish stunner is intended for survey tagging and population evaluation of certain species. The system is designed to operate from a 12-volt battery and draws 3 amps at maximum output. The unit is shock circuit protected and utilizes our highly efficient induction charging and switching to obtain the high — peak currents necessary for the high conductivity often found in brackish waters. A power adjuster con­trols the duration of the pulse, therefore controlling the current flowing in the water. The pulse repetition rate is factory set at 25 pulses per second. The ratio of the pulse’s “on” to “off” time is controlled by the power adjuster control. The output voltage with a load of 500 ohms is over 300 volts at its peak at a cor­responding current of over half an amp. No load volt­age rises to a high value and open-circuit operation must be avoided. Five hundred ohms correspond to a water resistance representing a typical freshwater pond found in southern New Hampshire.

At these parameters, the power dissipated into the water is around 25 watts and is effective up to 10 feet from the boat.

The effectiveness of the system is dependent on the following:

• Is the target fish within the area?

• Are the fish bottom dwellers?

• The fish size. Larger fish are easier to stun than the smaller ones.

• The water temperature may be too cold. This is important for proper operation.

Subassembly Pretest

Figure 24-7 Fully assembled unit

Intended for bottom fish such as catfish.

Preferred Method

Subassembly Pretest

May not work that well for
scale fish Water
temperature should be

above 70 F for best



Subassembly Pretest

Subassembly Pretest

• Use of ihe correct dragline, chains, wire mesh, and weights for the particular fish. Several examples are shown in Figure 24-8.

Please nole that the system utilizes a floating out­put, which means you do not have to use the electri­

Separate drag leads about 3 to 10 feet.

Will depend on water properties. Experiment for best results.

The area between the electrodes is where the fish will be affected Most fish will swim towards the positive electrode where as they get closer they become stupefied and stunned The above sketch shows the use of the floating output approach where no ground is required either to the boat or externally

You may ground the negative lead using the boat or motor as the contact now requiring only the use of one drag line electrode.

Chains must be allowed to drag on bottom

A multidrag line may be made by using a Insulated boom and eyeboltsto attach the chains. Electrical contact can now be made to each chain by the two output leads creating an electnc field between the chains Any fish between the chains will experience the effect. A tether bndle is made from nylon гора with voltage lead taped or tie wrapped to secure Note thet thle approach

should not be used in waters with a lot of bottom debris that can snag the device.

Boom may be mounted to transom using longer nylon father tines as shown in preferred method

An electrified survey is made by attaching 2 conductive loopa mounted at the ends of a wooden boom piece Our test model was made as shown with a separation of approx 3 feet between loops. One loop is connected to the positive output lead and the other to the negative There is no grounding U6ed as current must only flow between the loops The hendte was made from a 6-foot length of 1 x 3 pine with 4 screws attaching It to the boom section The bare wire loops were press-fitted into pre-drilled holes through the boom whare they ware epoxied in place. We used yfe" copper tube With approx 16“ diameter for our model as it is reasonably self-supporting and can be easily reformed if accidentally bent.

The voltage feed wires can also be slid into the holes for the loopa or can be attached to the loopa by soldenng or using a wi cismp The voltage leads are run up along the sides of the handle where they are connected to the shocker We actually mounted the shocker and 8 D cell betteries to the handle, making a completely self-contained system The voltage leads are tapad or clamped Into place.

cal system ot the boat or the boat itself as an elec­trode. If it is metal, you may choose to do this for cer­tain applications. This is simply done by connecting the negative output lead to the -12 VDC input or craft common, forcing a grounded return.

Figure 2Ч-В Electric fishing probes

A floating output provides a certain degree of safety for the operator because he or she must make actual contact with both output leads simultaneously to get shocked. If you now ground one of the output leads, it is possible to get shocked just by being in water that may be inside the boat and making acci­dental contact with only one of the output leads.

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