MFJ-974B – Balanced Line Tuner – 300W 6-80M


The MFJ-974B is a fully balanced true balanced line antenna tuner. The MFJ-974B gives you excellent current balance, a very wide matching range(12-2000 Ohms) and covers 10-80M continuously including all WARC bands. Handles 300 watts SSB PEP and 150 watts CW.

SKU: 53-449 Category:


For decades, the Johnson Matchbox has been the standard of comparison for balanced line tuners. But, it had a severely limited matching range and covered only 80, 40, 20, 15 and 10 meters. The MFJ-974B is its successor. It meets today’s needs and even surpasses the Johnson Matchbox’s outstanding performance.

MFJ-974B - Balanced Line Tuner - 300W 6-80M
MFJ-974B - Balanced Line Tuner - 300W 6-80M

Tuning is fast and easy – just three tuning controls. You can even adjust for highly efficient broadband low-Q operation or use higher Q when you encounter extreme loads.

The MFJ-974B tunes any balanced lines including 600 Ohm open wire line, 450/300 Ohm ladder lines, and 300/72 Ohm twin lead – shielded or unshielded.

The MFJ-974B is a fully balanced wide-range T-Network using four gear driven 1000 Volt air variable capacitors and a high-quality air wound tapped inductor for 80-10 meters and a separate inductor for 6 meters. The tuning components are mounted symmetrically to ensure electrical balance. A 1:1 current balun is placed on the low impedance 50 input side to convert the balanced T-Network to an unbalanced operation.

MFJ-974B - Balanced Line Tuner - 300W 6-80M
  • 10-80M
  • Handles 300W PEP, 150W CW
  • Fully balanced ‘T’ match network
  • 1:1 current balun
  • Cross needle SWR/Wattmeter 30/300W ranges
  • High-quality air wound tapped inductor
  • 4 gear 1000V air variable capacitors
  • 3 tuning controls
  • 12V DC illuminated meter
  • Size: 190 x 152 x 203 mm 
  • Matches 600 Ohm open wire, 450, 300 Ohm ladder lines, 300/72 Ohm twin, coax & random wires

Additional information

Weight 1.5 kg