MFJ MFJ941B free download

File name MFJ941B.pdf

MFJ-941B VERSA TUNER II INSTRUCTIONS Thank you very much for purchasing the MFJ-941B Versa Tuner II. GENERAL INFORMATION The MFJ-941B is designed to match virtually any transmitter to almost any antenna, including dipoles, inverted vees, verticals, mobile whips, beams, random wires, and others fed by coax lines, balanced lines, or a single wire, A 1:4 balun is built in for connection to balanced lines. This unit will handle up to 300 watts of RF output power from the transmitter from 160 through 10 meters. The MFJ-941B will monitor either SWR or RF transmitter power in two ranges, 30W or 300W. The antenna selector switch allows switching to one of the two coax fed antennas (direct or through tuner) and either a balanced line antenna or random wire antenna. A bypass position allows switching to a dummy load or a direct coax antenna. The tuner is bypassed but not the meter circuit when antenna selector is switched to BYPASS, DIRECT COAX 1 or DIRECT COAX 2 positions. CAUTION! Do not use the MFJ-941B for over 300 watts of RF output power, even in the bypass or direct positions. Do not operate the antenna selector while transmitting. THE SWR/WATTMETER The SWR/wattmeter of the MFJ-941B can be used with the tuner or by itself. The SWR/wattmeter is between the transmitter and the tuner when the antenna switch is in the COAX 1, COAX 2, or WIRE/BAL position. The SWR meter is sensitive down to approximately 5 watts RF output, The SWR reading will not be accurate for a transmitter power of less than 5 watts. To read RF transmitter output power, simply push the SWR/WATT control in and set to either 30 or 300, At position 30, the meter will read a maximum of 30 watts. At position 300, the meter will read a maximum of 300 watts. To read SWR, turn the SWR/WATT control, with the control pushed in, for a full-scale deflection and when pull the control out for the SWR reading. Note: The SWR sensitivity must be reset for each power level to obtain an accurate reading. INSTALLATION 1. Install the MFJ-941B between the transmitter and the antennas, A coax line is connected between the transmitter and the SO-239 coax connector marked TRANSMITTER on the tuner. 2. One or two coax fed antennas may be connected to the SO-239 coax connectors marked COAX 1 and COAX 2. Note: Coax 1 and coax 2 antennas can be connected directly to the transmitter by turning the antenna selector to COAX 1 DIRECT OR COAX 2 DIRECT, 3. A random wire antenna may be connected to the five-way binding post marked WIRE. The random wire should be long, high, and as clear of surrounding objects as possible. Do not ground the random wire antenna and make sure that the tuner is well grounded to the transmitter. A five-way binding post, marked GND, is provided for ground connection 4. A balanced line fed antenna may be connected to the two five-way binding posts marked BALANCED LINE, along with a jumper wire from the WIRE binding post to the adjacent BALANCED LINE bi