MFJ-259C HF/VHF SWR Analyzer
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| Frequency | 0.53-230 MHz (nine overlapping bands, no gaps) |
| Bands | MW through 230 MHz (530 kHz-230 MHz) |
| Power | Antenna analyzer - generates its own ~20 mW / 3 Vpp test signal into 50 ohm (a VFO, not synthesized; harmonics better than -25 dBc). Powered by 10 AA cells or external 11-16 V DC; built-in NiMH/NiCd charger. |
| Modes | SWR, resistance R, reactance X (magnitude only - no sign), impedance |Z| and phase, return loss / reflection coefficient, capacitance (pF), inductance (uH), coax loss / length / distance-to-fault, frequency counter, RF signal generator |
| Year | 2014 |
| rf | SO-239 (UHF female) test/antenna port, 50 ohm (used for all SWR/impedance measurements) |
| freq counter | BNC - frequency-counter input only (max 2 Vpp; never DC) |
| dc in | 2.1 mm coaxial, 13.8 V DC center positive |
| power req | 10 AA cells, or external 11-16 V DC (ideal 13.8 V at ~150 mA; max 18 V unloaded), 2.1 mm center positive |
Estimated (unverified): Weight is not published in the manual or by MFJ (community figures are roughly 1.5-1.9 lb with 10 AA cells). The original MFJ-259 dates to approximately 1996; the 259C specifically is 2013/2014.
A self-contained antenna test station in one battery-powered handheld: SWR, impedance, capacitance, inductance, coax loss, a frequency counter, and a signal generator, with no computer and no calibration routine. It connects directly via SO-239, works with the transmitter off, and its analog meters make dip-tuning easy. Coverage spans 530 kHz to 230 MHz, and for two decades it was the de-facto standard ham analyzer.
It shows the magnitude of reactance but not its sign, so you must tune to infer inductive vs capacitive (true of the 259D as well). It is single-port only - no transmission/S21 measurement - and the analog meters are less precise than digital. Inexpensive sweep analyzers like the NanoVNA now offer more, including reactance sign, for far less. It runs through AA cells quickly, and MFJ build quality varies. It is discontinued, so it is a used-market buy.
For two decades the standard ham antenna analyzer, and still a fast, no-computer way to check SWR and impedance, trim an antenna, or analyze a coax run in the field. Its big caveat is the magnitude-only reactance reading; a NanoVNA does more for less and shows the sign. But for quick, calibration-free measurements with real analog needles to watch, the 259C (or its 259D successor) is still a handy tool - now found used since MFJ closed.
For the better part of three decades, the MFJ-259 was the antenna analyzer most hams owned. The 259C is the third major version, and it does a job that used to take a bench full of instruments: connect it to an antenna or a length of coax, dial in a frequency, and it tells you the SWR, the impedance, and the resonant point - generating its own low-power test signal so your transmitter stays off the air the whole time.
It is more than an SWR meter. The 259C reads resistance and reactance, impedance magnitude and phase, capacitance in picofarads and inductance in microhenries, coax loss and length and distance to a fault, and it doubles as a frequency counter and a weak signal generator. Coverage runs from 530 kHz up to 230 MHz, split across nine overlapping bands selected by two switches, so there are no dead gaps - just a band knob to set. The readout is a two-line LCD backed by a pair of analog meters, one for SWR and one for impedance, which are easier to watch than digits when you are slowly tuning something for a dip.
One limitation is worth knowing before you trust a reading: the 259C shows the magnitude of reactance but not its sign, so it cannot by itself tell you whether a load is inductive or capacitive - you infer that by nudging the frequency and watching which way the number moves. This is a property of its bridge-and-diode design, not a defect, and it carried through even to the later 259D. Power comes from ten internal AA cells or an external 12-volt supply, with a built-in charger for rechargeables (set the internal jumper correctly, or it will cook non-rechargeable cells).
Unlike an in-line meter such as the Diamond SX-200, which reads while you transmit, the analyzer works with the radio off - exactly what you want when trimming a new antenna or matching a wire to a tuner like the MFJ-969. Inexpensive sweep instruments like the NanoVNA now do more for less and show the sign of reactance, but the 259C remains a fast, no-computer, no-calibration tool that many operators still prefer in the field. MFJ stopped manufacturing in 2024, so it - and its 259D successor - are now used-market items.