MFJ 934 Manual Antenna Tuner Artificial Ground

User Manual: Pdf MFJ--934 Antenna Tuner Artificial Ground

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General Information
- Meter Lamp
Using The MFJ-934
Adjustment Procedure
Tuning Chart
In Case Of Difficulty
Grounding Hints
Antenna Hints
- Location
- Matching Problems
MFJ-934 Artificial Ground
Adjusting The Artificial Ground
Tuning Out Reactance of Long Ground Leads
Tuning Chart

MFJ-934 Tuner/Artificial Ground Instruction Manual 1 MFJ-934 Antenna Tuner/Artificial Ground IMPORTANT: PLEASE READ ENTIRE MANUAL BEFORE ATTEMPTING TO OPERATE THIS EQUIPMENT. THIS UNIT DOES NOT PROVIDE A DC OR LOW FREQUENCY EARTH GROUND FROM THE COUNTERPOISE TERMINAL. A SEPARATE WIRE MUST BE CONNECTED FROM THE STATION GROUND BUS TO AN ELECTRIC GROUND. THE LONG WIRE AND BALANCED LINE TERMINALS ON THE BACK MAY HAVE AREA. DO NOT PLACE ANY COUNTERPOISE OR NON-COAXIAL FEED WIRES NEAR METALLIC OR RF SENSITIVE DEVICES. General Information The MFJ-934 is a 300 watt (175 watts on 160 meters) RF output power antenna tuner and artificial ground system that will match any transmitter or transceiver to virtually any antenna. A special circuit in this tuner cancels the reactance of a ground lead or counterpoise, and reduces problems caused by RF "in the shack". Forward power, reflected power, ground current, and SWR can be read on the wattmeter's illuminated cross-needle meter. The MFJ-934 tuner section uses a "T" network and covers all bands between 160 and 10 meters. This network will work with dipoles, inverted-vees, verticals, mobile whips, beams, random wires, and many other antennas. The MFJ-934 has rear panel connectors for coaxial, single wire or two wire feedlines. A built-in 4:1 balun allows the use of balanced open wire, twinlead, or twin-axial feedlines. SWR/Wattmeter and Ground Current Meter An illuminated cross-needle meter measures the FORWARD and REFLECTED power, ground current, and the SWR. The meter's full scale forward and reflected power range is controlled by the right METER RANGE switch. If your transmitter has more than 30 watts of output power, set this switch to the 300W (button in). If your transmitter has less than 30 watts of output, use the 30W switch position (button out). Forward power is displayed on the left-hand FORWARD meter scale when the FORWARD CURRENT button is out. Read directly from the scale in the 300 watt position. In the 30W position the forward power scale must be divided by 10. Reflected power is read on the right-hand REFLECTED meter scale. This scale indicates 60 watts full scale when the 300W power sensitivity is selected, and 6 watts when the 30W forward power range is selected. This scale must be divided by 10 when using the 30W power range position. The most accurate power readings occur in the upper half of the meter scales. To accurately measure power with a less than perfect match, the reflected power should be subtracted from the forward power reading.

MFJ -934 Instruction Manual 2 SWR is measured by observing the crossing point of the forward and reflected power needles. No cumbersome or time consuming SWR sensitivity adjustments are required with this type of meter. The SWR is read directly from eight red SWR curves ranging from 1:1 to infinity. Simply observe the red SWR curve closest to where both needles cross, and read the SWR value of the curve. Ground current is indicated on the Forward meter scale when the FORWARD CURRENT meter switch is depressed and locked. Interconnections

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