MFJ VersaTuner III -962D Manuals

INSTRUCTION MANUAL CAUTION: Read All Instructions Before Operating Equipment COPYRIGHT 2013 MFJ ENTERPRISES, INC. C Model MFJ-962D VERSION 5B MFJ ENTERPRISES, INC. 300 Industrial Park Road Starkville, MS 39759 USA Tel: 662-323-5869 Fax: 662-323-6551 Requires 9VDC Battery or 12VDC Source for Meter Operation MFJ-962D Instruction Manual 2 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-962D Instruction Manual 3 Introduction The MFJ-962D is a "T" network roller inductor tuner with built-in antenna switching, RF power and SWR metering and a 1:1 balun. The largest amplifiers that can safely be used include the Heathkit SB- 200 and 201, Collins 30L1, and Ameritron's AL-600 and AL-811 series of amplifiers. This tuner is designed for maximum RF output power levels of 800 watts carrier or PEP on 80-10 meters, and 500 watts carrier or PEP on 160 meters. It is designed to match 50 ohm output amplifiers, transmitters or transceivers to virtually any antenna. Peak and average forward power, reflected power, and SWR are displayed on the wattmeter's illuminated cross-needle meter. The MFJ-962D uses a roller inductor "T" matching network. It continuously tunes all frequencies from 1.8 through 30 MHz. It will match dipoles, inverted-vee's, verticals, mobile whips, beams, random wires, and many other antennas. The built-in balun will work with balanced open wire, twinlead, or twin-axial feedlines. An internal six position antenna-selector switch selects two separate coaxial line outputs either in tuned (with tuner's matching network in line) or direct (no matching circuit) configurations, a balanced line output, and a coax bypass position for accessories such as an external dummy load. Long wire antennas can be connected to the center connector of the coax connector. Understanding Power Ratings There are no standardized power rating systems for tuners. The names used (i.e. 3 kW Tuner) carry over from the time when amplifiers were rated by peak power input, and not the true RF power output. For example, the one thousand watt Johnson Matchbox was rated to handle a 1000 watt plate modulated AM transmitter (four kilowatts PEP transmitter input and 3000 watts PEP RF output). The Heathkit SB-220 was called a two kilowatt amplifier, and the rated CW output was approximately 600 watts. Matching tuners were called 2 kilowatt tuners, and these tuners safely handled 600 watts of CW power and 1200 watts PEP SSB. The FCC has changed the power rating system of amplifiers, and tuners no longer follow amplifier power ratings. Most typical 1500 watt tuners remain able to safely handle 400-600 watts CW, and 600- 900 watts PEP SSB. Load conditions and control settings also greatly affect the power handling capability of the tuner. T- networks typically handle more power on higher frequency bands into higher load impedances. The worst operating condition for T-network tuners are low impedance capacitive reactance loads. T- network tuners always handle the least power when operated on 160 meters into low impedance capacitive reactive loads. Power Requirement The upgraded MFJ-962D requires a power source to run its SWR/Wattmeter circuitry. Power may come from one of two sources: 1.) 9-Volt Battery: To install a 9-volt battery, access the internal holder and snap clip by removing the 12 cabinet screws and lifting off the tuner cover. The holder is mounted on the upper right corner of the front panel. We strongly recommend installing a battery, even if you intend to use an external power source. Doing so provides backup voltage to operate the meter and also prevents the battery snap clip from floating loose inside the cabinet where it could contact high RF potentials. If you elect to omit the MFJ-962D Instruction Manual 4 battery, make sure the snap clip is anchored solidly to the battery holder where it was wedged for shipping. To extend battery life, the tuner has built-in RF-sensing that applies power to the meter electronics only when a transmit signal is applied. After a short period of transmitter inactivity, power is removed automatically. Important Note: The 9-V battery powers only the meter electronics. It does not power the meter LEDs. You must supply external DC to illuminate the SWR meter. 2.) 12-VDC External Power: The Meter Lamp power jack is located above the Transmitter connector on the rear panel. Apply power from any filtered dc wall adapter (MFJ-1312D or equivalent), or use your station's 13.8-Vdc supply. A cord fitted with a 2.1-mm plug is supplied with the tuner for this purpose. If you make your own supply cord, connect +12 volts to the center pin and ground the outer sleeve, as shown below: + - + - 2.1 mm Important Note: You don't need to disconnect the battery when using external dc power. It is protected from back-feed and won't be damaged by the other source. Important Warning: Never connect an ac-voltage or positive-ground source to the Meter Lamp jack or permanent damage may result! Peak Reading SWR/Wattmeter The cross-needle meter measures the peak or average FORWARD power, REFLECTED power, and SWR. The illuminated cross-needle meter operates with the antenna tuning circuit in or out of line. The wattmeter can be used without the tuning network by setting the ANTENNA SELECTOR to either of the two COAX DIRECT positions of the antenna selector. The wattmeter is active in all positions of the ANTENNA SELECTOR. The meter's full scale forward and reflected power range is controlled by the left POWER switch that selects 2000W (HI) or 200W (LO). If your transmitter runs more than 200 watts of output power, set this switch to the 2000W HI (in) position. If your transmitter has less than 200 watts of output, set this switch to the 200W LO switch position (out). Peak envelope power (PEP) is measured when the PEAK or AVG POWER push button (right-hand side) in placed in the PEAK (in) position. Peak power and average power values are equal with steady unmodulated carriers, FSK, or FM. The meter reading on these modes will be the same whether the PEAK / AVG button is pressed or released. On SSB, the PEP meter reading should be twice the average power with two tone test modulation. On SSB, the ratio of PEP to average power varies with different voice characteristics. With most voices, the PEP reading is three to five times higher than the average voice power reading. The most accurate peak envelope power readings are obtained only with sustained carrier, voice or two tone test modulation. During normal voice modulation, the wattmeter will typically indicates only 70% of the true peak envelope power. Forward power is displayed on the left-hand FORWARD meter scale. This scale is calibrated from 0 to 200 watts and is read directly in the 200 watt position. Each picket (scale mark) represents 5 watts