MFJ-941B VERSA TUNER II INSTRUCTIONS Thank you very much for purcha sing the MFJ-941B Versa Tuner II. GENERAL INFORMATION The MFJ-941B is desig ned t o match virtuall y any transmitter to a lmost any antenna, includi ng dipoles , inverted vee s, verticals, mobil e whips, beams, random wires, and othe rs fed by c oax 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 transmi tter from 160 through 10 meters. The MFJ-941B will m onitor 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 a ntenna selector is swi tched to BYPASS , DIRECT COAX 1 or DIRECT COAX 2 positi ons. CAU TION! Do not use the MFJ -941B for over 300 watts of RF output power, e ven in the b ypass or direct positions. Do not ope rate t he ante nna selector while transmitting . THE SWR/WATTMETER The SWR/wattmeter of the MFJ-941B can be used with the tuner or by itself. T he SWR/wattmeter is between the transmitter and t he tuner when the a ntenna swi tch is in the COAX 1, COAX 2, or WIRE/BAL position. The SWR meter is sensi tive down to approximately 5 watts RF output , The SWR reading wi ll not be a ccurate for a transmitter power of less than 5 wat ts. To read RF transmitter output power, simply pus h the SWR/WATT control i n and set t o either 30 or 300, At positi on 30, t he meter wil l read a maximum of 30 watt s. At position 300, the mete r will read a maximum of300 watts. To read SWR, turn the SWR/WATT control, wi th the control pushed in, for a full-scale deflection and when pull the control out for the SWR reading . Note: The SWR sensiti vity must be reset fo r each power level to obtain an accurate reading. INSTALLATION 1. Install the MFJ -941B between the transmitter and the antennas, A coax line i s connected between the transmitter and the SO-239 coax connector marked TRANSMITTER on the tuner. 2. One or two coax f ed antennas may be connected to the SO-23 9 coax connector s 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 rando m wire antenn a may be con nected to the fiv e-way b ind ing post marked WIRE. The rand om wire should be long, hi gh, and as c lear of surrounding objects as possibl e. Do no t ground the random wire antenna a nd make sure tha t the t uner is well g rounded to th e transmitter. A five-way bindi ng post, marked GND, is provided for ground connec tion 4. A bal anced li ne fed antenna may be connected to the two fiv e-way bi ndi ng p osts mark ed BALANCED LINE, along with a jumper wire from the WIRE binding post to th e adjace nt BALANCED LINE binding pos t, as indicated by a dot ted line on t he MFJ-941B, This couples the MFJ -941B to the balanced line through a 1:4 balun. NOTE: Either a balanced line or random wire MFJ-941B Instruction Sheets http:/ /members.aceweb.com/ n6mm/tech/MFJ941B.htm 1 of 3 4/1/2011 2:19 PM
