4
BROADCAST & MULTIMEDIA
short wave broadcasting
common requirements of the international broadcaster family limited available land use concerning antenna field consideration of radiation hazard zone and interference to nearby installations shortest lead time to start off operation highest flexibility in terms of coverage as to actual and future requirements highest reliability, even under 24 hour operation condition design, operational and technical advantages lowest tolerance of outages full remote control, fault & performance monitoring continued operation of existing equipment during installation works best investment efficiency
China
11
BROADCAST & MULTIMEDIA
THALES Rotatable Antenna Array
for Short Wave Broadcasting
Aspects of Radio Engineering
BROADCAST & MULTIMEDIA
coverage ….
transmission with different pattern modes into different directions of azimuth
全波段短波接收机
成功地实现远距离覆盖 通过固定的或移动接收机接收信号 数字广播给短波广播新的推动力
2
BROADCAST & MULTIMEDIA
Simple ideas behind .....
一个简单的中央竖井包含三个功能: 旋转轴 为天线网络提供全部的动态或静止的支撑 安装ATU控制、射频以及基础装置 Access to all specified frequency bands of the allocated shortwave broadcasting range Back-to-back arrangement of a low band and a high band curtain antenna, each with its own reflector screen Electric control logic operates the entire network and assures antenna is turned in the direction of the respective coverage area over the shortest possible path Rotation never to exceed 180°; accordingly changeover time never to exceed more than three minutes for a 180° rotation
4/4, 4/2, 2/4, 2/2 4/4, 4/2, 2/4, 2/2
Oman
China
Broadcast System Frequency 5.9-26.1 MHz Transmitter 500 kW Completed 2003 Modes Low band High band
4/4, 4/2, 2/4, 2/2 4/2, 2/4, 2/2 4/4
3
BROADCAST & MULTIMEDIA
Simple ideas behind .....
Smooth starting and braking to standstill with no jolting Constant, quick acceleration and delay High rotation speed of 1 degree per second High positioning accuracy of < 1 degree Retrofit to any shortwave transmitter for carrier power level of up to 500 kW per transmitter High antenna gain from 18 up to 24 dB Perfect DC grounding, with number of insulators [spacer, hanger, supports] minimized All operational functions monitored and remote controlled Horizontal and vertical beam shaping (optional) through different modes of operation, like AHR 4/4, 4/2, 2/4, 2/2 [Standard Performance for the option]
4/4, 4/3, 4/2, 2/4, 2/3, 2/2 4/6, 4/4, 4/2, 2/6, 2/4 12 Systems 2 Systems
Nauen, Deutsche Telekom AG
Broadcast System Frequency 5.9-26.1 MHz Transmitter 500 kW Completed 1997 Modes Low band High band
6
BROADCAST & MULTIMEDIA
the answer
短波转动天线
7
BROADCAST & MULTIMEDIA
Main Structural Components
中央反射支架 检修车用钢缆
ቤተ መጻሕፍቲ ባይዱ
单边反射支架 支撑平 台 主塔架 平台斜支撑
振子支撑
低频振子
中央圆筒 混凝土基础
8
高频振子
BROADCAST & MULTIMEDIA
STUDIO
短波 TX
RFI RFI RFI RFIFrankin the the Night 17850 Stranger h Night 17850 17850 17850 1245 Frank h the RFI the 1245 Frank h the 1245 h Night Sinatrah Night Frankin 17850 Sinatra Sinatra Stranger inkHzkHzkHzkHzkHz 1245 Stranger inStranger in 1245 StrangerNightSinatra
18
BROADCAST & MULTIMEDIA
equivalent to
one self-supported and rotatable high band / low band curtain antenna
9
BROADCAST & MULTIMEDIA
references
High lighted …..
Issoudun, TDF
ALLISS-System Frequency 5.9-26.1 MHz Transmitter 500 kW Completed 1995/1996 Modes Low band High band France French Guyana
13
BROADCAST & MULTIMEDIA
coverage ….
full flexibility
14
BROADCAST & MULTIMEDIA
outdoor array feeding system …..
Mode HR 4/4
schematic presentation .... red lines active ...
principal Antenna layout
360o coverage
star-shaped arrangement
six pairs of high band / low band curtain antennas type AHRS… with slew facilities support structures transmission line & outdoor switch system polygon-shaped arrangement
THALES 短波广播用转动天线
概要
BROADCAST & MULTIMEDIA
短波广播
通过不同电离层和地 面之间一次和多次反 射实现远距离的电磁 波辐射
F2 Layer F1 Layer E Layer D Layer
250 - 400 km 175 - 250 km 110 km 50 - 90 km
5
BROADCAST & MULTIMEDIA
short wave broadcasting
Further expectation of the international broadcaster family availability of all non-tropical short wave frequency bands switch to different horizontal and vertical antenna patterns best efficiency by short RF transmission lines suitable permanent VSWR measurement junction perfect lightning protection and grounding system easy maintenance due to good accessibility of all major components best possible security for operators staff high corrosion protection of all steel members long life cycle long term availability of spare parts comprehensive training of operators staff