CESTRON HQ

GENERAL DESCRIPTION

QUADRANT ANTENNAS

Omni-directional transmitting antennas are most favoured when it is required to provide same time coverage of areas surrounding the transmitter site which extend up to a radius of 1300 km, depending on the transmitter power. If a single frequency operation is targeted to reach listeners day and night without retuning the receiver, a simple and therefore attractive design is the quadrant antenna.

HQ antennas consist of horizontal bent dipoles, the bent angle of which may vary from 60° to 90°, depending on the specified horizontal radiation pattern (deviation from perfect omni-pattern).

According to the ITU publication from May 11th 2001 «Transmitting Antennas for HF Broadcasting» quadrant antennas are designated by HQ n/h, whereby:

H Horizontal polarisation of the antenna
Q Quadrant type
n The number of dipoles stacked vertically
h Height of the lowest dipole above ground in wavelengths

To realize maximum bandwidth the «slenderness ratio», i.e. the ratio of dipole length to equivalent dipole diameter, is selected for best broadband characteristics and the dipole is designed as an open multi-wire cage. State of the art design allows the operation of HQ antennas over two adjacent frequency bands out of the shortwave broadcasting spectrum, as defined by WARC allocations.

Technical Highlights: