MFJ-986
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| Frequency | 1.8-30 MHz (incl. MARS/WARC) |
| TX power | 1500 W (Rated 3 kW PEP SSB amplifier INPUT = 1500 W PEP SSB OUTPUT (MFJ's own figures). A true legal-limit-output tuner) |
| Modes | SSB, CW, AM, FM, digital |
| rf in | SO-239 (transmitter) |
| rf out coax1 | SO-239 (coax 1) |
| rf out coax2 | SO-239 (coax 2) |
| balanced | ceramic feedthroughs (via TrueCurrentBalun) |
| ground | wing-nut |
| dummy load | external (selected by antenna switch) |
| power req | None (passive); meter lamp 12 V DC / 9 V battery |
The easy-tuning legal-limit MFJ manual tuner: its differential capacitor collapses the usual three-knob T-network down to two controls and gives a single, broadband minimum-SWR point, so you spend far less time re-tuning. It handles 1500 watts output, has a current balun on ceramic feedthroughs for balanced line, and uses an AirCore roller for low-loss matching.
It is still a manual tuner you adjust by hand, just with fewer knobs, and the roller contact wears over time. No 6-meter coverage, and (unlike the 989D) no built-in dummy load - the antenna switch selects an external one. As an MFJ product it is now discontinued (manufacturing ended 2024), so units are new-old-stock.
The simplest-tuning legal-limit MFJ manual tuner: the differential-capacitor design means two-knob operation and a single broadband match point at 1500 watts output. For an operator who wants legal-limit hand-tuning with less fiddling than a conventional T-network, the 986 is the pick; the conventional-T 989D adds a built-in dummy load, and the Palstar AT2K is the premium route.
The MFJ-986 is MFJ's 'Differential-T' tuner, and its defining trick is the differential capacitor: a single component replaces the two variable capacitors of a normal T-network, so the whole tuner comes down to just two controls - one capacitor and the roller inductor. That gives a single, broadband minimum-SWR setting rather than the interacting three-knob hunt a conventional T-network demands, which means much less constant re-tuning as you move around a band.
On power it is, despite the '3 kW' in its name, a 1500-watt-output tuner: MFJ's own specification reads '3 kW PEP SSB amplifier input power (1500 watts PEP SSB output power)' - the old input-versus-output convention, stated plainly. It covers 1.8 to 30 MHz including MARS and WARC, uses an AirCore roller inductor with a 3-digit turns counter, reads power on a lighted peak/average cross-needle meter (2000/200-watt ranges), and brings balanced line out through a TrueCurrentBalun on high-voltage ceramic feedthroughs. Wide-spaced capacitor plates let it run full power without arcing.
It is still a manual tuner - you adjust it by hand, just with fewer knobs - and the roller's wiping contact wears over time. Unlike the 989D it has no built-in dummy load (its antenna switch selects an external one), and there is no 6-meter coverage. MFJ stopped manufacturing in 2024, so the 986 is now a new-old-stock item around its last $480 list price. For an operator who wants legal-limit hand-tuning with the least fiddling, the differential-T design is genuinely easier to live with than a conventional T-network.