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MFJ 259D 280 kHz - 230 MHz plus 220 MHz (1.25 Meter) Antenna SWR Analyzers are compact, battery-powered RF impedance analyzers. They combine four basic circuits; a 100-140 kHz and 280 kHz to 230 MHz variable frequency oscillator, a frequency counter, a 50 ohm RF-bridge, and an 8-bit micro-controller. These analyzers make a wide variety of useful antenna or impedance measurements, including coaxial cable loss and distance to an open or short. Although primarily designed for analyzing 50 ohm antenna and transmission line systems, MFJ 259D Analyzers also measure RF impedances between a few ohms and several hundred ohms.
They also function as a signal source and frequency counter! Their frequency range of impedance measurement is done with several overlapping bands. The accuracy of the analyzers is enhanced by the use of special microwave zero-bias Schottky detectors with matching compensating diodes. They are compensated to provide the best possible linearity with both high and low impedance loads, making the A/D converter's 0.5 percent resolution the primary limitation.
This Antenna Analyzer has two frequency-range knobs. The new lower-frequency coverage allows analysis of 137 kHz, 472-479 kHz and 160 through 1.25 meter antennas, including MW (AM broadcast) and shortwave frequencies. The extended coverage for the new 630 and 220 meter bands is a very worthwhile addition!
MFJ 259Ds may be used to test:
*Antennas: SWR, impedance, reactance, resistance, resonant frequency, and bandwidth
* Antenna tuners: SWR, bandwidth, frequency
* Amplifiers: input and output matching networks, chokes, suppressors, traps, and components
* Coaxial transmission lines: SWR, length, velocity factor, approximate Q and loss, resonant frequency, and impedance
* Filters: SWR, attenuation, and frequency range
* Matching or tuning stubs: SWR, approximate Q, resonant frequency, bandwidth, impedance
* Traps: Resonant frequency and approximate Q
* Tunes circuits: Resonant frequency and approximate Q
* Small capacitors: Value and self-resonant frequency