SHORTWAVE RADIO BROADCAST ANTENNAS

AMPEGON ANTENNA SYSTEMS HQ

GENERAL DESCRIPTION


QUADRANT ANTENNA

photo Ampegon Antenna Systems HQ Omni-directional transmitting antennas are most favored 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 re-tuning the receiver, a simple and therefore attractive design is the so-called quadrant antenna.

ITU Regulations apply a special alphanumeric code to describe quadrant antennas. In its most general form the antenna is denoted by HQ n/h, whereby:

H horizontal polarisation of the antenna

Q quadrant type

n the number of dipoles stacked vertically in horizontal rows

h height of the lowest dipole above ground in wavelengths of the bottom row of dipoles

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

It is obvious that simple dipoles cannot be operated over the entire shortwave broadcasting spectrum, although the "slenderness ratio", i.e. the ratio of dipole length to equivalent dipole diameter, is selected for best broadband characteristics and the dipole is executed as an open multiwire cage.

State of the art design allows the operation of HQ antennas over the entire frequency range, covering two adjacent frequency bands out of the shortwave broadcasting spectrum, as defined by WARC allocations.

TECHNICAL HIGHLIGHTS


TECHNICAL SPECIFICATIONS
Antenna Type Range (in km) Frequency Range Radiation Pattern Typical Gain (dBi)
Up to 1300 1000 to 4000 2000 to 6000 3000 to 8000
HQ 1/h
(Quadrant)		 X


max. 2 adjacent bands in the SW range omni-directional 8 - 10
The height (h) is according specific performance requirements.
The stated range is assuming single-hop transmission and can be seen as a rough guideline for design purposes. In any case the range is dependent on specific ionospheric propagation conditions.
Specifications may change without notice