MEASALL KC980B

A wideband 20–200MHz hybrid-loop directional antenna for transmitter hunting, radio direction finding, interference investigation and signal-source location with spectrum analysers and reconnaissance receivers.

The MEASALL KC980B is the lower-frequency hybrid-loop model in the KC980X directional antenna family, designed to provide useful directionality across the 20–200MHz range.

Its handheld format makes it particularly useful for locating unknown transmitters, tracking down sources of radio interference, investigating electromagnetic interference and carrying out portable signal surveys both indoors and outdoors.

Find Where a Signal Is Coming From

Used with a suitable spectrum analyser, monitoring receiver or other RF measurement instrument, the KC980B allows the operator to physically rotate the antenna while observing the received signal level.

This makes it useful for transmitter hunting, radio direction finding, interference source location, near-field EMI troubleshooting and general RF reconnaissance.

More Directional Than a Simple Loop

A conventional electrically small loop primarily responds to the magnetic field and normally produces a figure-eight radiation pattern with two opposing lobes.

The KC980B uses a split loop with additional resistive loading so that the structure also responds to the electric field. Because the electric and magnetic responses have different phase characteristics, the two combine to create a predominantly cardioid directional pattern across the intended operating range.

The result is a handheld antenna that can provide a more useful indication of which direction a signal source lies in.

The Largest Hybrid Loop in the KC980X Range

Of the KC980B, KC980S and KC980C hybrid-loop antennas, the B model has the largest loop circumference. This makes it the version specifically intended for the lower part of the range.

MEASALL specifies useful directionality from 20 to 200MHz, making the KC980B the natural choice when your work is concentrated below the ranges covered by the smaller KC980S and KC980C.

Sweep the Antenna and Watch the Signal Level

The KC980B's main lobe is intentionally fairly broad, so accurate direction finding is best carried out by slowly sweeping the antenna and carefully observing the signal level on the connected instrument.

Where the peak is difficult to judge directly, compare the positions on either side of the suspected bearing where the signal falls by a similar amount. The centre point between them provides a useful estimate of the main-lobe direction.

Designed for Field Use

The antenna measures approximately 430 × 295 × 90 mm excluding the cable and weighs approximately 800 g including the cable. A permanently attached cable approximately 1.35 m long, measured from the handle, gives the operator room to move the antenna independently of the connected analyser or receiver.

For direction-finding work, use the KC980B within its specified 20–200MHz range. Outside the intended range the radiation pattern changes and directionality progressively deteriorates, so another KC980X antenna may be more appropriate.

KC980X Series User Manual

View the MEASALL KC980X manual for further information on antenna theory, direction-finding technique, radiation patterns, VSWR and the complete KC980X range.