MFJ MFJ-870 User Manual

MFJ Enterprises, Inc.

300 Industrial Park Rd

Starkville, MS 39759 USA

MFJ-870 SWR & Power Meter Instruction Manual

This SWR & Power meter is a highly accurate RF meter for measuring Forward Power, Reflected Power, and VSWR.

Main Features:

∙Large meter display for easy reading.

∙Forward RF power readings, switchable to indicate either average power of Peak Envelop Power (PEP) for SSB and AM transmitters.

∙Reflected RF power readings.

∙VSWR ratios.

∙Illuminated meter.

∙Convenient control for easy operation.

Model	MFJ-870
Frequency Range	1.6 - 60 MHz
Power Range	1W to 3KW
Power Scale	30W, 300W, 3KW
Maximum Power	3KW (up to 1 minunte maximum)
Accuracy	+/- 10% (AVG)
VSWR	Min Power required = 3 Watt for F.S.D.
Input/Output Impedance	50 Ohms
Input/Output Connectors	SO-239
Dimensions (W/H/D) in	7.5 X 4.25 X 3
Weight (lbs)	1 lb 11oz
Accessories	Instruction Manual & Lead wire with DC Plug
Front Panel

Back Panel

Explanation of Features:

1.Meter Display: Indicates Forward/Reflected Power in Watts and SWR ratio.

2.Function Switch: Selects Forward Power, Reflected Power, SWR SET, and SWR.

3.Range Switch: Selects RF Power Ranges of 30W, 300W, and 3KW.

4.SWR SET Control Knob: Sets full scale deflection when measuring SWR.

5.AVG/PEP Monitor: Selects Average or PEP RF Power Readings.

6.Meter Zero adjust: Mechanical zero adjustment for meter needle.

7.TX Connector: Coax connector to transmitter 50 OhmRF output.

8.ANT Connector: Coax connector to 50 Ohm antenna system.

9.13.8V DC connection for meter illumination.

Note: If meter lighting is required, use the DC cable enclosed and connect it to a 13.8V DC source.

FORWARD POWER MEASUREMENT

1.Set the FUNCTION switch to the ‘FWD’ position.

2.Set the radio transceiver to transmit and read the scale corresponding to the Power range selected (30W, 300W, or 3KW)

3.When the AVG/PEP button is ‘out’ the meter reads average RF power. When the AVG/PEP button is depressed the meter reads Peak Envelope Power for use with SSB and AM transmissions. In this mode there will be a slow rise and decay time.

REFLECTED POWER MEASUREMENT

1.Set the FUNCTION switch to the ‘REF’ position.

2.Set the radio transceiver to transmit and read the scale corresponding to the Power range selected (30W, 300W, or 3KW)

3.When the AVG/PEP button is ‘out’ the meter reads average RF power. When the AVG/PEP button is depressed the meter reads Peak Envelope Power for use with SSB and AM transmissions. In this mode there will be a slow rise and decay time.