Differential-T Antenna Tuner
MFJs innovative Differential-T Tuner uses a differential capacitor that makes tuning easier than ever. It gives minimum SWR at only one setting. Broadband coverage ends constant re-tuning. The MFJ-986 is a rugged roller inductor antenna tuner that handles 3KW PEP SSB amplifier input power (1500 Watts PEP SSB output power). It tunes 1.8 - 30 MHz continuously, including MARS and WARC bands.
MFJs exclusive AirCore Roller Inductor gives absolute minimum SWR -- something tapped inductors just cant do. 3-digit turns counter plus a spinner knob gives precise inductance control so you can quickly retune your frequency. A lighted peak and average reading Cross-Needle meter shows SWR, forward and reflected power at a single glance!
You get 6-position antenna switch that lets you select two coax lines and/or random wires (direct or through tuner), balanced line and external dummy load. The MFJ TrueCurrentBalun for balanced lines minimizes feedline radiation that causes field pattern distortion, TVI and RF in you shack. Ceramic feedthru insulators for balanced lines withstand high voltages and temperatures.
Replacing two variable capacitors with a single differential capacitor gives a wide range T-Network tuner with only two controls -- a tuning capacitor and a roller inductor. Simple 2-knob tuning makes tuning easier than ever. You get minimum SWR at only one setting a broadband response that ends constant re-tuning. Youll spend your time QSOing instead of fooling with your tuner. The compact cabinet has plenty of room to mount the roller inductor away from metal surfaces for highest Q -- you get high efficiency and more power into your antenna.
Wide-spaced tuning capacitor plates let you run high power without arcing. MFJs lighted Cross-Needle Meter shows you SWR, forward and reflected power simultaneously. It reads peak or average power on 2000 or 200 Watt ranges. The lamp has on/off switch nd uses 12 VDC or 110 VAC with MFJ-1312D, $14.95.
More tuners use a voltage balun that forces equal voltages on the two antenna halves. It minimizes unbalanced currents only if the antenna is perfectly balanced -- not the case with practical antennas. The MFJ-986 uses a true current balun to force equal currents in the two antenna halves -- even if the antenna is not perfectly balanced! The MFJ TrueCurrentBalun gives superior balance over voltage baluns and minimizes unbalanced current. This reduces field pattern distortion, concentrates your power for a stronger signal plus it reduces TVI and RF in your shack caused by feedline radiation.