MFJ MFJ-842 Manual de usuario

INSTRUCTION MANUAL

CAUTION: Read All Instructions Before Operatin

Equipment

MFJ ENTERPRISES, INC.

300 Industrial Park Road

Starkville, MS 39759 USA

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

Model MFJ-842

VERSION 1A

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-842 Mobile VHF/UHF SWR/Wattmeter Instruction Manual

MFJ-842 Mobile HF/VHF SWR/Wattmeter

Introduction

The MFJ-842 Mobile VHF/UHF SWR/Wattmeter measures forward and reflected power

and SWR simultaneously and is designed to operate on 140-525 MHz. The MFJ-842 has

two power scales, which are selected with a push button switch. The high power scale

measures 0-150 Watts forward power and 0- 50 Watts reflected power. The low power

scale measures 0-15 Watts forward power and 0-5 Watts reflected power. The MFJ-842

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: 140-525 MHz

Input Impedance: 50 Ohms

Power Range: 15 and 150 Watts Forward Power

5 and 50 Watts Reflected Power

Power Accuracy: 10% at full scale

Minimum Input Power: 1 Watts

Connectors: UHF (M type)

Dimensions: 3.35”W x 3.43”H x 3.74”D

Weight: 0.62 lb

Lamp Input Power: 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-842.

MFJ-842 Mobile VHF/UHF 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 150 Watts and the reflected power scale is on 50 Watts. When the

button is pushed out, the forward power scale is on 15 Watts and the reflected

power scale is on 5 Watts. If your transmitter/amplifier runs more than 15 Watts

of output power, push the button in for 150 Watts. If your transmitter runs less

than 15 Watts of output power, push the button out for 15 Watts.

2. Forward power is displayed on the left-hand FORWARD meter scale. This scale

is calibrated from 0 to 150 Watts and is read directly in the 150W (in) position.

Each picket (scale mark) represents 5 Watts below 30 Watts, 10 Watts between 30

and 150 Watts. In the 15W (out) position, the forward power scale must be

divided by 10. Each picket represents 0.5 Watt below 3 Watts, 1 Watts from 3 to

15 Watts.

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

Reflected power is 50 Watts full scale when the 150W (in) power scale is

selected, and 5 Watts full scale when the 15W (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. NOTE: In the case of 220 MHz band measurement, both forward and

reflected power must be converted with the following formula:

DIRECT READOUT X 0.7 = ACTUAL 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.

MFJ-842 Mobile VHF/UHF SWR/Wattmeter Instruction Manual

Calibration

The MFJ-842 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 140 or 525 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 a mid-band frequency.

3. With the POWER RANGE button pushed in for the 150 Watt scale, transmit 150

Watts as indicated on the reference meter. Adjust the HI FWD trim pot to set the

forward power scale to 150 Watts.

4. With the POWER RANGE button pushed out for the 15 Watt scale, Transmit 15

Watts as indicated on the reference meter. Adjust the LO FWD trim pot to set the

forward power scale to 15 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.

6. With the POWER RANGE button pushed in for the 50 Watt reflected scale,

Transmit 50 Watts as indicated on the reference meter. Adjust the HI REF trim

pot to set the reflected power scale to 50 Watts.

MFJ-842 Mobile VHF/UHF SWR/Wattmeter Instruction Manual

Meter Calibration (cont.)

7. With the POWER RANGE button pushed out for the 5 Watt reflected scale,

Transmit 5 Watts as indicated on the reference meter. Adjust the LO REF trim

pot to set the reflected power scale to 5 Watts.

8. SWR requires no calibration. Read SWR directly from the crossing point of the

forward and reflected needles.

Figure 2: Test Setup

Figure 3: Trim Pot Location (Bottom View of MFJ-842)

Transmitter/

Transceiver

Standard

Reference

Wattmeter

MFJ-842

Mobile

SWR/

Wattmeter

50-Ohm

Dummy Load

LO REF

HI FWD HI REF

LO FWD

MFJ-842 Mobile VHF/UHF 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.

MFJ-842 Manual

Version 1A

Printed In U.S.A.

300 Industrial Park Road

Starkville, MS 39759

Tabla de contenidos

Otros manuales de Instrumento de medición de MFJ

Manuales populares de Instrumento de medición de otras marcas

Suaoki

Suaoki D40 Manual de usuario

Elster

Elster BK-G1.6 Manual de usuario

Endress+Hauser

Endress+Hauser Deltabar FMD71 Manual

Duratool

Duratool D03128 Manual de usuario

Vega

Vega VEGAPULS 65 Manual de usuario

Tonghui

Tonghui TH2618B Manual de usuario

Tenmars

Tenmars TM-801 Manual de usuario

MSR

MSR 145 Manual de usuario

TPS

TPS WP-82 Manual de usuario

ELMETRON

ELMETRON CP-511 Manual de usuario

PCB Piezotronics

PCB Piezotronics 003C30 Manual de usuario

Tenma

Tenma 72-10465 Manual de usuario

Endress+Hauser

Endress+Hauser Proline Promag 50 Especificaciones técnicas

Siemens

Siemens SITRANS F Coriolis FCT030 Manual de lista de piezas

KLINGER

KLINGER CMF V Series Manual de usuario

EXFO

EXFO FTB-2 Manual de operación y mantenimiento

Keysight

Keysight M8290A Manual de usuario

ADTEK

ADTEK MW-5 Manual de usuario