The CIA-HF complex impedance analyser represents AEA's latest innovation in wireless communications test instruments. The CIA-HF is housed in a portable, battery-operated, custom plastic package with graphical LCD presentation. Operating within a frequency range of 400 kHz to 54 MHz, the company says it provides virtually all of the capabilities of its SWR-121 HF Analyst, plus a number of features that are unparalleled in this price range.
The CIA-HF combines a sweep frequency generator, impedance bridge and liquid crystal graphical display in a rugged and compact package. For convenient field use, it can be powered by internal AA alkaline, Nicad batteries or an optional wall charger. An optional softcase is also available for unit storage or hands-free operation using the swivel hook or neck strap.
The CIA-HF analyser was primarily designed to assist technicians in designing, tuning, and troubleshooting RF communications antennas, baluns, tuned feedlines, filters and duplexers. In the RF design laboratory, the CIA-HF also functions as a vector impedance analyser. Additional features include a direct reading capacitance meter, inductance meter, Q meter, graphical grid-dipper and stable single or sweep frequency signal generator. The insertion loss of a filter or cable can be determined using the return loss readout at any frequency in the unit's 400 kHz to 54 MHz range. The instrument also helps the user understand impedance characteristics, specifically in the relationship of antenna impedance below, through and above resonance.
The instrument offers new measurement modes:
* Absolute impedance graphical mode - similar to the SWR graphical display mode, this mode indicates the absolute impedance of an antenna or tuned circuit relative to frequency. For example, where the minimum point of a resonant yagi antenna would equal approximately 50 y, a U-shaped curve indicating the 'real' value of impedance at resonance would be displayed. This curve is useful in tuning an antenna or evaluating a non-functioning antenna.
* Reactance graphical mode -the X reactance graphical mode displays the reactance component of impedance relative to frequency over a user-selected frequency range. This curve is useful for quickly identifying the true resonance (not just the 50 y impedance point) of an antenna or tuned circuit. A multiple parameter digital display mode can be selected to demonstrate the inductance or capacitance of an antenna at a given frequency, as well as the conjugate match value of the inductance or capacitance needed to tune the antenna to resonance.
* Resistance display mode - in this mode, the R (real) resistance component of impedance is graphically displayed relative to frequency. This is useful in determining the effects of frequency changes on the resistance of an antenna match.
* Vector impedance mode - here a graphical presentation of an actual impedance vector is shown. The real and imaginary (reactive) components of the vector are shifted 90°, with the real component represented on the Y axis and the imaginary component on the X axis. This display mode allows the user to gain enough resolving power to find the true resonance of an antenna or tuned circuit. At a glance, the relative magnitudes of the real and imaginary components of impedance and especially the phase angle, can be determined at any given frequency.
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