Description

KC980X represents a series of directional antennas featuring a consistent handle design. They are primarily used as accessories for spectrum analyzers and reconnaissance receivers, supporting applications such as transmitter detection, radio direction finding, near-field electromagnetic interference (EMI) troubleshooting, and, for certain models, field strength measurement. This series is characterized by a wide frequency range, moderate size, ease of portability, and robust construction, making it well suited for handheld use in both indoor and outdoor environments.

As of now, the KC980X series includes the following models:

1.KC980A and KC980R Both are pure magnetic field antennas with minimal response to electric fields. The main difference between the two extended models, A and R, lies in the size of the loop. Shielded loop antennas respond to magnetic fields over a broad frequency range and perform better at low frequencies (e.g., below 30 MHz) than hybrid loops or other types. However, at higher frequencies, magnetic field antennas generally have lower gain than electric field antennas. Therefore, the KC980A and KC980R are mainly used for detecting low-frequency electromagnetic waves.

Shielded loop antennas do not have a strictly defined nominal frequency range. Their usable frequency depends on the strength of the original electromagnetic field, required sensitivity, and the desired antenna directionality. At low frequencies, because they behave as “small antennas,” their gain decreases as frequency decreases; however, when electromagnetic radiation is strong enough, sufficient reception levels can still be achieved. This type of antenna exhibits a high standing wave ratio (SWR) and is not suitable for transmission.

Directionality

At low frequencies, in the direction parallel to the antenna plane, the KC980A/R behaves nearly as an omnidirectional antenna, with a disc-shaped radiation pattern. When used for direction finding, attention must be paid to distinguishing the front from the back. Starting at around 15 MHz, the radiation pattern in the antenna plane begins to split, with a larger front lobe and smaller rear lobe, which is advantageous for direction finding. In the direction perpendicular to the antenna plane, the pattern takes on a figure-eight shape, with the main lobes pointing radially outward. Therefore, when the antenna is used in a vertical orientation, it can be used for horizontal direction finding, while when laid flat, it can be used to roughly estimate the signal’s elevation angle.

Gain

The table below presents the near-field received signal levels (in dBm) of the KC980S, KC980A, and KC980R antennas when receiving signals from the same electrically small transmitting antenna. Measurements were taken in a typical large indoor environment. It is evident that the KC980A and KC980R demonstrate a clear advantage at low frequencies.

The KC980X series is primarily used for direction finding. Except for the KC980D, when used for field strength measurement, please note that the above data represent the antenna gain in the antenna’s direct forward direction and may not reflect the maximum gain.

Mechanical Parameters

Note: Parameters have random errors and are for reference only.