Model MFJ-822

INSTRUCTION MANUAL

CAUTION: Read All Instructions Before Operating Equipment

VERSION 1A

MFJ ENTERPRISES, INC.

300 Industrial Park Road

Starkville, MS 39759 USA

Tel: 662-323-5869 Fax: 662-323-6551

DISCLAIMER

Information in this manual is designed for user purposes only and is not intended to supersede information contained in customer regulations, technical manuals/documents, positional handbooks, or other official publications. The copy of this manual provided to the customer will not be updated to reflect current data.

Customers using this manual should report errors or omissions, recommendations for improvements, or other comments to MFJ Enterprises, 300 Industrial Park Road,

Starkville, MS 39759. Phone: (662) 323-5869; FAX: (662) 323-6551. Business hours:

M-F 8-4:30 CST.

MFJ-822 Mobile HF/VHF SWR/Wattmeter Instruction Manual

MFJ-822 Mobile HF/VHF SWR/Wattmeter

Introduction

The MFJ-822 Mobile HF/VHF SWR/Wattmeter measures forward and reflected power and SWR simultaneously and is designed to operate on 1.8-200 MHz. The MFJ-822 has two power scales, which are selected with a push button switch. The high power scale measures 0-300 Watts forward power and 0-100 Watts reflected power. The low power scale measures 0-30 Watts forward power and 0-10 Watts reflected power. The MFJ-822 utilizes an illuminated Cross-Needle meter to read the SWR from 1:1 to

∞. This compact

SWR/Wattmeter is rugged enough to take the abuse of brutal mobile and portable operation.

Specifications

Frequency Range:

Power Range:

1.8-200 MHz

Input Impedance: 50

30 and 300 Watts Forward Power

10 and 100 Watts Reflected Power

Power Accuracy: 10% at full scale

Dimensions:

Lamp Input Power:

UHF (M type)

3.35”W x 3.43”H x 3.74”D

12 VDC

Installation

1. Connect your transmitter to the connector labeled TX. on the back of the unit and connect your antenna to the connector labeled ANT. on the back of the unit. It is important that you use good quality coax and properly installed connectors.

2. An internal lamp backlights the meter scale. The lamp circuit requires 12 VDC supply such as the MFJ-1312B. Use a 2.1 mm coaxial plug with the center conductor positive and the sleeve ground.

3. To measure the power output capability of a transmitter/amplifier you should connect a quality 50-ohm dummy load to the ANT. connector of the MFJ-822.

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MFJ-822 Mobile HF/VHF SWR/Wattmeter Instruction Manual

Operation

1. The meter’s full-scale forward and reflected power range is controlled by the

POWER RANGE button. When the button is pushed in, the forward power scale is on 300 Watts and the reflected power scale is on 100 Watts. When the button is pushed out, the forward power scale is on 30 Watts and the reflected power scale is on 10 Watts. If your transmitter/amplifier runs more than 30

Watts of output power, push the button in for 300 Watts. If your transmitter runs less than 30 Watts of output power, push the button out for 30 Watts.

2. Forward power is displayed on the left-hand FORWARD meter scale. This scale is calibrated from 0 to 300 Watts and is read directly in the 300W (in) position.

Each picket (scale mark) represents 10 Watts below 60 Watts, 20 Watts between

60 and 300 Watts. In the 30W (out) position, the forward power scale must be divided by 10. Each picket represents 1 Watt below 6 Watts, 2 Watts from 6 to

30 Watts.

3. Reflected power is displayed on the right-hand REFLECTED meter scale.

Reflected power is 100 Watts full scale when the 300W (in) power scale is selected, and 10 Watts full scale when the 30W (out) power scale is selected.

4. The most accurate power readings occur in the upper half of the meter scales.

When trying to measure power with a less than perfect match, the reflected power should be subtracted from the forward power reading in order to find the true power.

5. The SWR is read directly from nine red SWR curves that range from 1:1 to

∞.

SWR is measured by observing the point where the forward and reflected power needles cross. The SWR is indicated by the red curve closest to the needle crossing point.

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MFJ-822 Mobile HF/VHF SWR/Wattmeter Instruction Manual

Calibration

The MFJ-822 has been calibrated at the factory. If it should ever need to be recalibrated, then follow this procedure:

Equipment Needed

1. Transmitter capable of supplying enough power to obtain ½ to full-scale reading at 14 or 21 MHz.

2. 50-ohm dummy load that is capable of handling full transmitter output power and has better than a 1.15:1 SWR.

3. Power meter of know accuracy. The calibration will only be as good as the standard reference meter.

4. 50-ohm cables capable of handling the power. RG-58/u is recommended. DO

NOT USE RG-59 or RG-11.

Meter Calibration

1. In order to calibrate the meter, you must remove the rear panel of the meter by removing the screw located in between the ANT. and TX. connectors. The trim pots used to set the needles are located on the bottom. Refer to Figure 2 for the

Test Setup and refer to the Trim Pot Location in Figure 3 for trim pot location.

2. Connect the Test Setup equipment as shown in Figure 2. Use a 50-ohm dummy load for the antenna. Set the Transmitter to the 14 MHz in the 20-meter band.

Watts as indicated on the reference meter. Adjust the HI FWD trim pot to set the forward power scale to 100 Watts.

Watts as indicated on the reference meter. Adjust the LO FWD trim pot to set the forward power scale to 100 Watts.

5. To set the reflected power, interchange the TRANSMITTER and ANTENNA coax cables so that the transmitter is connected to the ANTENNA connector and the dummy load is connected to the TRANSMITTER connector.

Transmit 100 Watts as indicated on the reference meter. Adjust the HI REF trim pot to set the reflected power scale to 100 Watts.

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MFJ-822 Mobile HF/VHF SWR/Wattmeter Instruction Manual

Meter Calibration (cont.)

Transmit 10 Watts as indicated on the reference meter. Adjust the LO REF trim pot to set the reflected power scale to 10 Watts.

8. SWR requires no calibration. Read SWR directly from the crossing point of the forward and reflected needles.

Transmitter/

Transceiver

Standard

Reference

Wattmeter

MFJ-822

Mobile

SWR/

Wattmeter

50-Ohm

Dummy Load

Figure 2: Test Setup

HI FWD

LO FWD

HI REF

LO REF

Figure 3: Trim Pot Location (Bottom View of MFJ-822)

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MFJ-822 Mobile HF/VHF SWR/Wattmeter Instruction Manual

Technical Assistance

If you have any problem with this unit first check the appropriate section of this manual.

If the manual does not reference your problem or reading the manual does not solve your problem, you may call MFJ Technical Service at 662-323-0549 or the MFJ Factory at

662-323-5869. You will be best helped if you have your unit, manual and all information on your station handy so you can answer any questions the technicians may ask.

You can also send questions by mail to MFJ Enterprises, Inc., 300 Industrial Park Road,

Starkville, MS 39759; by Facsimile (FAX) to 662-323-6551; or by email to [email protected]. Send a complete description of your problem, an explanation of exactly how you are using your unit, and a complete description of your station.

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300 Industrial Park Road

Starkville, MS 39759

MFJ-822 Manual

Version 1A

Printed In U.S.A.