Note
The MFJ-989D is a major overhaul of the 989 tuners, and was the last in the series. Improvements include new 500 uF air variable capacitors, a new AirCore roller inductor with a new fast-tune crank knob, a new TrueActive peak-reading cross-needle SWR/Wattmeter with brighter illumination, an improved high-voltage current balun, and a larger cabinet to help maintain hi-Q.
New large 500 pF air variable capacitors provide twice the capacitance for more efficient operation on 160 and 80 Meters. Specially shaped plates give low minimum capacitance resulting in an extremely wide matching range from 160 thru 10 Meters.
MFJ's AirCoreTM Roller Inductor with new fast-tune Crank Knob
New and improved AirCore Roller Inductor gives you lower losses, higher Q and handles more power with no self-resonances. Large, self-cleaning wiping contact gives excellent low-resistance connection without contact arcing or burning. The new fast-tune crank knob lets you reset your roller inductor quickly, smoothly and accurately. A precision gear driven 3-digit turns counter lets you accurately reset your roller inductor for quick band changing.
The TrueActive peak reading SWR/Wattmeter lets you read true peak or average power on all modes. Large, easy-to-read super-bright LED lighted cross needle meter lets you read SWR and forward/reflected (3000/300 watt ranges) power at a single glance. Uses 9-Volt battery and/or 12 VDC or 110 VAC with MFJ-1312D.
The new high voltage current balun lets you tune high and low impedance balanced lines without core saturation or voltage breakdown. It is constructed with two large 2 1/2 inch toroid cores and wound with high voltage wire connected to high-voltage glazed ceramic feedthrough insulators.
The antenna switch is made of two individual ceramic wafers wired in parallel. Extra wide spaced, heavy duty contacts handle extreme voltages and currents. You can select two coax antennas (directly or through tuner), balanced line/random wire, or built-in dummy load.
The 989D includes a full-size 300 watt non-inductive 50 ohm dummy load.
The more roomy cabinet helps maintain high Q. Vent holes keeps components cool. Non-stripping PEM nuts, wing-nut ground post, fire-retardant epoxy glass PC board, and heavy gauge wire throughout.
The MFJ-989D has a new nearly indestructable multi-color Lexan front panel. Its detailed logging scales and legends will be legible for a lifetime.
The tuner uses a wide range T-matching network. It gives you the widest matching range and is the easiest to use of all matching networks.
