MFJ-267 1.5kW Dry Dummy Load and SWR/Wattmeter Instruction Manual

1. Introduction

This manual provides detailed instructions for the proper use and maintenance of your MFJ-267 1.5kW Dry Dummy Load with Built-in Precision, True Peak-Reading SWR/Wattmeter. This device is designed for testing and tuning radio equipment, offering both a high-power dummy load and an accurate SWR/wattmeter for frequencies from DC to 60 MHz.

2. Safety Information

• High Power Warning: This unit is capable of handling up to 1.5kW. Always ensure proper connections and never exceed the specified power rating.
• Heat Dissipation: When used as a dummy load, the unit will generate significant heat. Allow adequate ventilation and avoid touching the unit during or immediately after high-power operation.
• Electrical Safety: Ensure all connections are secure before applying power. Do not operate the unit in wet or damp conditions.
• Proper Grounding: For optimal performance and safety, ensure your radio equipment and the MFJ-267 are properly grounded.

3. Product Overview

The MFJ-267 combines a non-radiating dummy load with a precision SWR/wattmeter. It features SO-239 connectors for easy integration into your antenna system.

Figure 1: Front view of the MFJ-267 unit, showing the meter display, controls, and SO-239 connectors.

3.1 Controls and Indicators

• Meter Display: Analog meter for SWR and power readings.
• Power Range Switch: Selects appropriate power range for accurate readings.
• SWR/Watt Switch: Toggles between SWR and Wattmeter functions.
• SO-239 Connectors: Input and output ports for RF connections.
• DC Input Jack: For optional external power supply to illuminate the meter backlight.

4. Setup

4.1 Initial Inspection

Before connecting, inspect the unit for any visible damage. Ensure all connectors are clean and free of debris.

4.2 Connecting to a Transceiver

1. Connect the output of your transceiver to the input SO-239 connector on the MFJ-267 using a high-quality 50-ohm coaxial cable.
2. If using the unit as a dummy load only, ensure no antenna is connected to the output of the MFJ-267.
3. If using the SWR/Wattmeter in-line with an antenna, connect the antenna to the output SO-239 connector of the MFJ-267.

4.3 Powering the Display Backlight

The meter display is functional without external power. However, for improved visibility in low-light conditions, an optional 12V DC power supply (not included) can be connected to the DC input jack to illuminate the backlight.

5. Operating Instructions

5.1 Using as a Dry Dummy Load

The MFJ-267 functions as a 50-ohm non-radiating dummy load, capable of handling up to 1.5kW. It is suitable for testing transmitters, tuning, and performing maintenance without radiating an RF signal. Ensure the unit is properly ventilated during high-power transmissions.

5.2 Using the SWR/Wattmeter

1. Select Function: Use the SWR/Watt switch to select either SWR or Wattmeter mode.
2. Select Power Range: Choose the appropriate power range (e.g., 300W, 1500W) using the power range switch. Always start with a higher range to avoid damaging the meter.
3. Transmit: Apply a low-power RF signal from your transceiver.
4. Readings: Observe the meter for SWR or power readings. The meter provides true peak-reading capabilities for accurate power measurement.
5. Frequency Range: The SWR/Wattmeter is accurate for frequencies from DC to 60 MHz.

6. Maintenance

• Cleaning: Clean the exterior of the unit with a soft, dry cloth. Do not use abrasive cleaners or solvents.
• Storage: Store the unit in a dry, dust-free environment when not in use.
• Inspection: Periodically check all connectors and cables for wear or damage.

7. Troubleshooting

• No Meter Backlight: The backlight requires an optional 12V DC power supply. Ensure it is connected and functioning if you desire illumination. The meter itself operates without external power.
• Inaccurate Readings: Verify all connections are secure and that you are using the correct power range setting. Ensure your coaxial cables are in good condition.
• Unit Overheating: Reduce transmit power or duration. Ensure adequate ventilation around the unit.
• No Readings: Check the SWR/Watt switch position and ensure RF power is being applied to the input.

8. Specifications

9. Warranty and Support

For warranty information, technical support, or service, please refer to the official MFJ Enterprises, Inc. website or contact their customer service department directly. Keep your purchase receipt for warranty claims.

MFJ Website: www.mfjenterprises.com