MFJ-818 Mobile SWR/Wattmeter
Instruction Manual
1
MFJ-818 Mobile SWR/Wattmeter
Introduction
The MFJ-818 Mobile SWR/Wattmeter measures forward and reflected power and SWR
simultaneously and is designed to operate on 1.8-30 MHz. The MFJ-818 has two power
scales, which are selected with the top panel push button switch. The high power scale
measures 0-300 Watts forward power and 0-60 Watts reflected power. The low power
scale measures 0-30 Watts forward power and 0-6 Watts reflected power. The MFJ-818
utilizes a large illuminated three-inch Cross-Needle meter to read the SWR from 1:1 to
∞
. A slide switch turns the back light on or off. This compact SWR/Wattmeter is rugged
enough to take the abuse of brutal mobile and portable operation.
Figure 1
: MFJ Mobile SWR/Wattmeter
Installation
1. Connect your transmitter to the connector labeled TRANSMITTER and your
antenna to the connector labeled ANTENNA. 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. A slide switch turns the internal lamp
on or off.
3. To measure the power output capability of a transmitter/amplifier you should
connect a quality 50-ohm dummy load to the ANTENNA connector of the MFJ-
818.
