MFJ-225 HF/VHF Two-Port Graphic Antenna Analyzer
MFJ-225 is a compact completely self-contained handheld analyzer. On the bench it becomes a full-fledged two-port (S21) desktop machine when teamed up with your PC. Using powerful IG-miniVNA freeware, you'll run detailed data analysis and then print out stunning color-graphic plots to document your work! All the basic analyzer functions you've come to depend on plus a host of advanced features like builtin LCD graphics, two-port VNA measurement, PC-Interface using IG-miniVNA freeware, and precise DDS frequency control . . . yet still easy-to-use!
Get a big picture every time with MFJ-225's built-in back-lighted 3-inch LCD graphic display. Make fine circuit adjustments using full-screen easy-to-view SWR bar graph, capture vivid swept displays for SWR, impedance, return loss, phase angle, more! Operation is simple, you can adjust the center frequency, tuning step, and sweep width instantly while viewing your plot, literally shaping it before your eyes. Tunes from 1.5 MHz to 179.9 MHz with rock-solid stability and no gaps. That's because the MFJ-225's VFO is a state-of-the-art programmable DDS (direct digital synthesis) generator with pin-point 1-kHz frequency resolution. DDS control means no mechanical band switches or tuning elements, just a reliable velvet-smooth optical encoder to glide across the spectrum.
The MFJ-225 DDS stimulus generator also gives you a leveled -5 dBm signal source for driving mixers, low-power amplifiers, filters, networks, diplexers, and antennas on the test range. And, your test signal is always clean, with over -50 dBc of harmonic and spur suppression. That's better than many precision lab generators costing thousands of dollars! Connect an external step attenuator, and it becomes a highquality signal generator for peaking sensitive receivers and preamplifiers.
The MFJ-225 simultaneously compiles and displays all important parameters you need on a single screen, giving you a wider range of results at a glance. You'll work faster and smarter without the inconvenience of scrolling through menus or making tedious conversions to get your data.
What the MFJ-225 Measures:
• SWR (1:1 to 9.9:1)
• Complex Impedance (R+jX)
• Impedance Magnitude (Z)
• Return Loss (RL, 0-30dB)
• Phase (0-180°)
• Capacitance (0-9999pF)
• Inductance (.1uH-80uH)
• Cable Length (0.5-45m)
• Cable Loss (0-30dB)
In addition to traditional single-port (S11) reflected-power measurements, MFJ features an invaluable advantage of making two-port (S21) forward-power measurements, essential for optimizing filters, diplexers, matching networks, etc. It bridges the gap between a simple scalar analyzer and true vector-analysis performance.
“Advanced features” conjure visions of greater complexity and more buttons to push . . . not true for MFJ-225! The graphic display is "advanced" because it places more information at your fingertips without needless scrolling and searching. Also, the layout is unique with three large soft-touch selector buttons located on the front panel next to the screen and a large side-mounted frequency control knob conveniently positioned for your right hand. Everything is located where it needs to be for intuitive operating and unobstructed screen view!
Easy To Power
The MFJ-225 runs from multiple power sources to suit almost any operating environment. In the field, it powers itself for up to four hours using three self-contained AAA NiMh cells. On the bench, it accepts any convenient external 12-volt DC power source or a good- quality 12-volt AC wall adapter like the MFJ-1312D. It also runs off your PC's USB jack. Connecting an external power source automatically initiates recharging of the internal NiMh batteries with a LED charge indicator that goes out when the charge cycle is complete.
In order to maintain out-of-the box accuracy, all analyzers require periodic calibration checks -- a potentially time-consuming operation that may require special RF loads and step-by-step procedures. However, the MFJ-225 uses built-in firmware to perform its entire calibration routine in less than a second! Simply initiate the "calibrate" command and you're done!
The MFJ-225 has the same tough all aluminum MFJ-style enclosure you've come to rely on in the field and on the bench. It's fully shielded and constructed to take its lumps while continuing to deliver dependable performance year after year.
MFJ-225 requires 4 NiMh AAAcells or optional power adapter MFJ-1312D
PC interface requires a USB Type-B cable.
Analyzer's OUT port is SO-239. IN port is SMA-female.
3 3/32 W x 6 1/8H x 1 1/2D inches.
Weight with batteries is 1-lb., 2-oz.
Typical 12V power consumption is 230 mA, increasing to 550 mA when batteries are recharging at max.