R A D I O F R E Q U E N C Y S Y S T E M S

T h e C l e a r C h o i c e i n W i r e l e s s ™

Please visit us on the internet at http://www.rfsworld.com T h e C l e a r C h o i c e i n W i re l e s s ™

3rd quarter 2003

Tuning to the key of RF

RFS cable for Washington metro

Cellular on the rise in Syria

DTV climbs mountains in Taiwan

Wireless in a ‘wide brown land’

The Radio Frequency Systems Bulletin

2

Through our participation in the inaugural

UK and Spain digital terrestrial television

roll-outs, and latterly those throughout

the USA and Asia Pacific, Radio Frequency

Systems has accumulated a wealth of

experience in the practical side of

transmission site upgrades. Not only have

we pioneered the development of

adjacent channel combining technology,

our end-to-end RF solutions have been

adopted by terrestrial broadcasters the

world over, and we remain committed

to meeting the specific requirements

of each and every digital terrestrial

television broadcaster.

This month the entire broadcast world

converges on the city of Amsterdam for the

International Broadcasting Convention (IBC),

a five-day meeting of minds and broadcast

technologies, where undoubtedly much of

the focus will be on digital television in its

various guises. Two things are certain:

digital terrestrial television is a reality and

here to stay. RFS has the solutions.

Digital terrestrial television seems to be

a technology that is still searching for a

means to establish a revenue stream

for broadcasters. What, then, is driving

its deployment?

Many broadcasters would argue that

government legislation has forced their

hand. Certainly the sale of RF spectrum has

brought revenue to the government in

many countries; moreover, the possibility of

sophisticated network programming and

interactive services could be said to bring

a nation into ‘the information age’.

Whatever the motive of a particular

government, the global market is certainly

seeing multiple licensing agreements

stipulating on-air dates, with analogue

switch-off scheduled for as early as 2006

in some countries.

In any case, digital terrestrial television was

inevitable. Free-to-air analogue terrestrial

television services have been the cornerstone

of the broadcast industry for decades, and

free-to-air digital terrestrial television is the

natural migration.

Pioneered by the UK, Spain and Sweden,

digital terrestrial television deployments

across the world are growing steadily.

High-power terrestrial broadcasters in the

US have converted around 50 per cent of

transmission sites to digital; and the Asia

Pacific region is making good headway with

advanced deployments in Australia, Singapore

and Taiwan. The countries of Western Europe

are also moving forward with both digital

terrestrial trials and deployment.

Since the conceptualization of digital

broadcasting in the early 1990s, Radio

Frequency Systems has been committed to

making it happen. The introduction of

digital services was clearly destined to

unleash a wave of new technologies and

renewed enthusiasm for broadcast infra-

structure deployment; this led RFS to

deploy its own extensive resources towards

developing innovative end-to-end solutions

for the next generation. The result is that

digital terrestrial broadcasters all over the

world are now looking to RFS to provide

the RF expertise and technology to

streamline the transition to digital.

Hailed as an even bigger development in

television than the introduction of colour

transmission, digital television offers an

enhanced television experience, with a

wealth of added features such as interactive

programming, high definition television,

customized channel ‘bouquets’ and increased

data broadcasting. Yet despite these

potential viewing advantages, the ongoing

challenge for terrestrial broadcasters has

been winning consumer acceptance.

The market models adopted for digital

television vary considerably from region to

region, country to country. High definition

television services, offering sharper pictures

for large television screens, have been the

focus of many terrestrial broadcasters—

particularly those in North America. However,

few terrestrial broadcasters have yet

experimented with digital multichannelling,

which provides the most efficient use of

spectrum and the opportunity for interactive

television. In many cases, networks have

simply commenced digital broadcasting of

the same fare offered via analogue.

3

Digita l terrestr ia l te levis ion: the natural migrat ion

E D I T O R I A L

03 EditorialDigital terrestrial television: the natural migration

04 What’s NewOptimizer® range adds multi-band functionality

Global solutions for long tunnel coverage

Future-proof in-building antennas

06 Network OptimizationTuning to the key of RF

09 Confined CoverageRFS cable for Washington Metro

10 Cellular Cellular on the rise in Syria

11 DTV DeploymentDTV climbs mountains in Taiwan

14 Regional FocusWireless in a ‘wide brown land’

16 RF ConditioningRFS and Nextel find the right combination

17 MicrowaveLightweight antennas withstand the winds

18 In TouchRFS presents DTV options at IBC 2003

Strong signs at Russian expo

Dallas DTV rises above the cedars

New power for online catalogue

PREVIEW: Wireless advances within

Dr Jörg SellnerChairman of RFS

RFS cable for Washington MetroThe emergency communications system of akey extension of the massive WashingtonMetro is brought on air using smooth wallradiating cable technology from RFS.

Tuning to the key of RF

As 2G cellular network operators focus onwringing higher performance out of existingassets, the key to network optimization maywell lie in tight RF footprint management.

14

10

Wireless in a ‘wide brown land’As third-generation cellular networks arrive in Australia, communications services are continuing toreach further into the country’s vast interior.

I N D E X

11

6

DTV climbs mountains in TaiwanTelevision broadcasting is poised to enter anexciting new era in Taiwan, as the process ofdigitization accelerates.

Jörg Sellner

IMPR

INT

Cellular on the risein SyriaAs the SyriaTel cellularnetwork expands andevolves to meet sub-scriber demand, RFScontinues to play animportant supportingrole.

9

Radio Frequency SystemsWorldWideWeb: http://www.rfsworld.com

Publisher: Jörg SpringerExecutive Editor/Editor Asia Pacific:Peter WaltersEditor EMAI: Alan WalpEditor Americas: Ann PolanskiManaging Editor: Dr Ellen GregoryProduction Editor: Regine KrügerArt Director: Marilu Krallmann

Authors: Allan Alderson, Dr Ellen Gregory, Zach Phillipps, Regine Suling

Photos: RFS archives, Shelton Muller, Bruce McIntyre, Nextel, Richland Towers, SyriaTel, stockimages p. 9, p. 15 and p. 19 from GettyImages.

Cover image: RFS archives, inform archieves

Cover art: Marilu Krallmann

Print: Print Design, Minden

Layout and Graphics:inform advertising, Hannover

Editorial Services:Relate Technical Communications, Melbourne

high-performance distributed feedback (DFB)

lasers, it provides particularly high-linearity,

excellent intermodulation performance

(IP3 levels of better than 50 dBm in the

downlink and 40 dBm in the uplink), and

up- and downlink noise levels lower than

6 dB. Gain is fully adjustable between 20 to

40 dB in 2-dB steps.

The robust and well-known T-BDA bi-

directional amplifier is used to regenerate

both uplink and downlink signals along

radiating cable or coaxial transmission lines

in long tunnel applications. The T-BDA may

be cascaded to a maximum of six BDAs,

extending the total RF link length by a

factor of seven. The T-BDA offers gain

adjustment, noise level and intermodulation

performance identical to that of the T-RU.

Both the T-RU and the T-BDA offer unrivalled

reliability in arduous environments, with a

mean time between failure (MTBF) of

greater than 50,000 hours. The units are

identical in form factor, are hoseproof (IP65),

and can operate in temperatures between

-20 to 45 degrees Celsius and humidity

levels of between 0 to 99 per cent.

Radio Frequency Systems now offers two

uniquely wideband point-source antennas,

specifically designed for in-building appli-

cations. Both the I-ATO1 omnidirectional

antenna and the I-ATP1 panel antenna

support a frequency range of 806 to

2500 MHz, ensuring the antennas provide

a truly future-proof in-building solution.

The broadband point-source antennas

support all major cellular bands in use

across North America and the ‘rest-of-the

world’ today, along with emerging

2 GHz-plus RF standards. These include

the 2.1 GHz third generation cellular

universal mobile telecommunications

system (UMTS), and the 2.4 GHz wireless

local area network (WLAN) IEEE 802.11b.

The antennas complement RFS’s world-

renowned RADIAFLEX radiating cable

range, and offer an alternative solution for

use in architectures where a distributed

point-source antenna system is preferred

to radiating cable. Specfically designed

for flush wall or ceiling mount in indoor

environments, the antennas are fabricated

in white ABS, and offer an elegant and

low-profile finish.

5

Future-proofin-bui ld ingantennas

W H A T ’ S N E W

Two important new cellular antenna families

in the high performance Optimizer range

are now available from Radio Frequency

Systems. Both antenna families—the

Optimizer 900/1800 dualband and the

Optimizer ‘side-by-side’—introduce the

superior performance characteristics of

the Optimizer cellular antenna range into

sophisticated multi-band configurations.

According to Patrick Nobileau, RFS Vice

President Base Station Antenna Systems,

multi-band antennas are proving

advantageous for operators seeking to

add services in higher frequency bands. In

developing countries, the success of global

system for mobile communications (GSM)

900 MHz services is increasingly leading to

the introduction of GSM 1800 MHz;

while elsewhere in the world, the migration

towards 2 GHz-plus third generation

technologies is a prominent issue.

“In either of these cases, operators are

faced with the same challenge: a limited

number of base station sites, environmental

impact issues, and constraints on capital

expenditure,” said Nobileau. “Multi-band

antennas allow a whole new service to

be added with a simple antenna

replacement.”

The RFS Optimizer 900/1800 dualband

antenna has been developed to meet the

requirements of operators adding 1800 MHz

services to existing GSM 900 networks.

Available in 2-metre (APX15GV-15DVB)

and 1.3-metre (APX13GV-15DVB) sizes,

the antenna comprises an 1800 MHz

array superimposed on a 900 MHz

chassis, resulting in a dualband antenna

that has exactly the same physical

dimensions as the single-band 900 MHz

model. Each band has individual

electrical specifications and supports

independent variable electrical tilt (VET)

from 0 to 10 degrees.

The Optimizer dualband antenna is the

next generation of RFS’s pioneering

dualband technology. “The new antenna

provides superior performance in both

bands—there is no loss of performance

of the existing 900 MHz service,” said

Nobileau. “This means that GSM 900

network planning and quality of service

are not affected.”

A different approach has been adopted

for the Optimizer ‘side-by-side’ antenna,

which is a modular arrangement of two

separate antennas under a shared

radome that is only slightly wider than a

single-band antenna. To be ultimately

available in a range of different frequency

combinations, the Optimizer APX15DV-

15WVL supports co-existent GSM 1800

and universal mobile telecommunications

system (UMTS) services.

The Optimizer 1800/2100 side-by-side

antenna complements the Optimizer

broadband APXV18-2065XXL series

(supporting GSM 1800, PCS 1900 and

UMTS—see STAY CONNECTED Q1 2003

issue—as a solution for operators introducing

third generation cellular services.

The Optimizer dualband and side-by-side

antennas both exhibit the superior

performance of the RFS Optimizer cellular

antenna family—including side lobe

suppression typically better than 20 dB

across the entire tilt and frequency range,

significantly increased gain, a uniquely-

wide 0 to 10 degrees of continuously-

adjustable variable electrical tilt, improved

front-to-back ratio (typically around 30 dB),

and compatibility with RFS’s remote tilt

technology, the Optimizer RT.

4

Optimizer®

range addsmult i -bandfunct ional i ty

W H A T ’ S N E W

Global solut ions for long tunnel coverageTwo important tunnel technology products

from Radio Frequency Systems now

combine to provide optimal long tunnel

coverage for all major commercial cellular

and emergency communications bands in

the world today. The existing T-BDA band-

selective bi-directional amplifiers, and the

new T-RU fibre-fed band selective remote

RF units, both support nine distinct bands.

These include: trans European trunked

radio (TETRA) 380 MHz, specialized mobile

radio (SMR) 800 MHz, code division multiple

access (CDMA) 800 MHz, Cellular bands ‘A’

and ‘B’ 800 MHz, global system for mobile

communications (GSM) 900 and 1800 MHz,

personal communication systems (PCS)

1900 MHz, and universal mobile telecom-

munications system (UMTS) 2100 MHz.

The new and extremely compact T-RU unit

supports fibre optic backbone extensions of

up to 20 kilometres in particularly long

tunnel applications. This important unit

integrates both an electrical to optical (e/o)

convertor, with a high frequency re-amplifier,

all in a compact 720 x 730 x 260-mm IP65

enclosure. As the T-RU unit is based on

Optimizer® 900/1800 dualband antenna

Optimizer® 1800/2100 ‘side-by-side’antenna

Nobileau reports that studies show a strong

correlation between C/I improvement and

the magnitude of suppression of antenna

upper side lobes. Maximizing side lobe

suppression has therefore become a

focal point for antenna designers and

manufacturers in the quest for interference

reduction. Where once side lobe suppression

was typically in the range of 12 dB, the

target is now 18 to 20 dB—with RFS

achieving typically better than 20 dB across

the entire tilt range with its Optimizer

antenna series.

“The smaller the side lobe compared with

the main lobe, the better the antenna

will fight co-channel interference,” says

Nobileau. “But if it’s not the first upper side

lobe that potentially interferes, it could be

the second—so every unwanted signal

needs to be as small as possible.”

Smyth agrees that the first step of RF

management should take place at the

antenna, citing electrical downtilt capability

as an advantage for cell planning and

management of modern mature networks.

While mechanical tilting of the antenna

beam is simple to implement, it has little

impact on spurious side radiation, and may

even increase interference from the rear

lobes. Electrical tilting technology, on the

other hand, tilts all lobes—main, rear and

side—to the same angle. This means that

side lobe radiation can be managed

across all tilt angles, providing greater

interference control.

Point of contact“The base station antenna is the primary

point of contact with the customer,” Smyth

says. “It seems strange to me that operators

would spend hundreds of thousands of

dollars acquiring a site and developing it,

only to quibble about the extra hundreds

of dollars invested in antenna technology

and its maintenance. What you’ve got

at the base station counts for nothing

control of the RF energy generated by an

antenna, the spurious side and rear

lobes can be thrust in the direction

of neighbouring or nearby cells, creating

the potential for interference. In mature

markets, where there are many coexisting

—and co-located—services and operators,

cell interference issues abound, providing

many headaches for network optimizers.

RF where it’s usefulThe need for improved control of RF energy

has led to ongoing developments in antenna

technology aimed at reducing

spurious emissions and providing

tighter control of the antenna

footprint.

“Antennas play a critical role in

network optimization—they are a

major part of RF management,”

says Vibhore Bharti, Manager RF

Planning with Indian cellular

operator, Idea Cellular. “Improving

antenna efficiency—the ability to

control frequency pollution—is a

vital element.”

“What is needed is a clean pro-

pagation of RF energy—putting

the energy where it’s useful and

not where it’s unwanted,” says

Nobileau. “The suppression of

side and rear lobes, and footprint tailoring

using electrical tilt, are therefore very

important. This is particularly so as cells

become smaller and smaller—the more

you tilt, the greater the potential

for interference.”

The impact of interference in GSM

networks is generally measured as the ratio

of carrier signal (C) to co-channel inter-

ference level (I)—or the C/I ratio—where

minimum C/I values for acceptable voice

quality are 9 to 10 decibels. It follows that

reducing interference will improve C/I, and

in turn yield improvements in audio quality

and network capacity.

After two decades of rampant development

in the cellular industry, it might now be a

period of consolidation and gradual

transition; but it is also a period of extra-

ordinary challenge. Not only do consumers

and business practitioners have high

expectations of the quality and availability

of cellular services, but the demand for

‘vertical’ technologies—such as data

services overlaid on existing 2G networks—

is escalating. Operators too are regarding

2.5G services as a potential means of

growing their businesses—particularly in

mature markets where subscriber take-up

rates have petered out.

As capital investment is minimized and

operators seek to maximize

returns from existing assets,

network planning and

optimization have

become more critical

than ever. Yet, the

more complex

the network,

the more

layers of

services, the

greater the number of

parameters that have to be

considered and made

compatible. With traffic

patterns shifting so readily

and networks interfering

with each other, the art of

network optimization has,

to the uninitiated, started

to look like ‘black magic’.

put the signal where it’s wanted, and keep

it from where it’s not wanted. So managing

RF is one of the basic steps in planning and

subsequently optimizing a network.”

“It’s a kind of puzzle,” adds Patrick Nobileau,

Vice President of Base Station Antenna

Systems for Radio Frequency Systems.

“With so many cells, if you want to optimize

your network, you have to make sure that

you transmit the energy without creating

too much of an overlap. This is particularly

important for CDMA systems, where the

same frequency is used for each cell.”

Careful frequency planning of networks

provides a measure of transmission quality

on a macro scale; however, the trouble-

shooting of problem areas invariably leads

to a spot of local tuning. In such cases, it is

the antenna beam that can be adjusted,

says Mende. “We use information from

the live system for measurements. Once

the results are analyzed, we can decide

how to change parameters such as

the antenna direction, downtilt, and

transmission power.”

However, mere tilting of the antenna beam

can be a cause, rather than a cure, of

co-channel interference. Without rigid

Head of radio planning systems for T-Mobile

in Germany, Wolf Mende, concurs with this

view. Key performance indicators (KPI) such

as hand-off success rate, call drop rate, hold

time, and congestion are continuously

monitored to provide indicators of areas

that might require tuning. “We also take

dedicated field strength measurements of

the involved base stations where they are

required,” Mende says. “These provide an

image of the real interference situation in a

network, as opposed to what we might

have predicted using models.”

Co-channel challengeBoth Mende and Smyth acknowledge that

one of the greatest challenges of network

optimization is controlling RF interference.

In global system for mobile communications

(GSM) networks, co-channel interference

degrades audio quality by masking low level

carrier signals; whereas in code division

multiple access (CDMA)-based networks,

capacity is depleted by interference, which

increases the noise floor. Either way, the

result is inferior network performance,

providing dissatisfaction to users.

“In mature networks, it’s not about

coverage. It really boils down to managing

interference,” says Smyth. “The object is to

76

As 2G cellular network operators focus on wringing higher performance outof existing assets, the key to network optimization may well lie in tight RFfootprint management coupled with sophisticated network monitoring tools.

“One of the earliest things that we

learned in the days of analogue was

that a cellular system never moves

out of the design phase,” says wireless

communications consultant, John Smyth,

who spent 15 years as National

Manager of RF Systems, Mobile Networks,

for Australia-based telecommunications

company, Telstra. “Infrastructure is being

added, traffic patterns are continually

changing—so you need to have

flexibility within the system to cope

with it.”

System flexibility is perhaps the

credo of network optimization,

which is a constant balancing

act between coverage,

capacity and the

increasingly important

quality of service.

“Because of this

demand for

flexibility,

operators need to keep

constant track of network

performance—twenty-four

seven,” says Smyth. “This is

the first step in optimizing a

network.”

N E T W O R K O P T I M I Z A T I O N

Tuning to the key of RF

Side lobe levels are suppressed to better than 20 dB in high performance antennas as a means of reducingco-channel interference.

Nobileau’s view is that remote tilt is just

another essential feature of the multi-

functional high performance antenna.

“First you need an antenna that can control

the side lobes; second, you need to be

able to activate it remotely; third, you

need to be able to feed the antenna with

the network management information

needed for the best possible optimization

scenario,” he says.

For the moment, however, the bottom line

is that operators in many countries are

having to deal with mature 2G markets

where subscriber growth has flattened out,

and this month’s balance sheet is the

commercial reality. It then comes down to

whether or not the network can handle the

demands placed upon it—particularly as

they are compounded by the additional

demands of general packet radio service

(GPRS) and enhanced data rates for global

evolution (EDGE) services.

The technology is available: not only high

performance antennas for controlling

interference, but also sophisticated

network monitoring tools to complete

the optimization loop. The key is to take a

long term view; the implementation of new

technologies now will provide immediate

results as well as equipping networks

for the future. All that remains is to take

the first step.

loadings, adding coverage challenges to

the optimization puzzle.

T-Mobile will launch its German UMTS

network in late 2003, and Mende is keen to

take note of its operation. “There are many

challenges awaiting us,” he says. “We

expect 3G networks to be more sensitive

to interference than GSM because the

network dynamics are different. We’ve

computed it all theoretically, but now the

time comes to see how

close we are.”

The anticipated optimi-

zation challenges of the

future have fuelled the

demand for remote

antenna tilting technol-

ogies—essentially, the

ability to adjust antenna

downtilt from locations

other than the top of the

tower. According to

Smyth, the benefits of remote tilting are

many: from eliminating the cost of hiring

equipment for tower access, to avoiding

impacting other operators with base

stations at the same site, and streamlining

regular tilting operations as might be

required during network redesign.

“The futuristic vision is for operators to

dynamically adjust the network as traffic

patterns change throughout the day,”

says Smyth. “I envisage there might emerge

a set of ‘presets’ for various traffic

situations; where all antennas move in a

coordinated fashion to a particular cell

plan. This would apply particularly to

CDMA-based systems.”

Mende has a similar dream, where ‘closed

loop’ control between network monitoring,

planning and operation exists. “It would be

advantageous to follow the network

dynamics; seasonal and weekly changes in

behaviour. We can see where the traffic

goes and then optimize those areas. In order

to achieve this quickly, we’d need remote

control of the antenna systems,” he says.

until you actually launch it out into the

aether and point it in the direction of the

customer.”

This raises an interesting issue to be

considered by network operators: the merit

of upgrading existing antenna technology

to higher performance antennas. According

to Nobileau, doing so provides an

incremental improvement in capacity that

defers the necessity of deploying next

generation services for the sole purpose of

meeting capacity demands.

Smyth believes that this path should be

attractive for operators seeking to maximize

returns from existing assets. “By replacing

existing antennas with higher performance

antennas, you achieve the flexibility to cope

with changes at a much lower cost. The

level of general interference will go down,

your drop-out rate will reduce, holding

times and utilization of the network will go

up,” he says.

Of a Manhattan USA operator that recently

replaced all base station equipment for an

entire network, he adds: “I would have

liked the opportunity to prove that by

spending about a tenth of the money in

upgrading to more advanced antenna

systems, they could also have achieved a

significant improvement in service and

increase in ultimate capacity.”

On the other hand, T-Mobile’s Mende is

more cautious: “Better antennas always

help,” he says. “As new sites are deployed,

it’s always good to look for the antenna

solution with the best interference

suppression. But it’s always a question of

whether to replace existing antennas!”

Evolving challengesAs networks continue to evolve and new

technologies emerge, the role of optimi-

zation will only increase—in terms of both

regularity and importance. For instance,

it is anticipated that 3G services such as

real-time video transmission will lead to

dramatic and unpredictable cell traffic-

8

Studies show a strong correlation betweenco-channel interference and the magnitudeof suppression of antenna upper side lobes.

Metro Center

Mt. Vernon Sq.

Gallery Pl.Chinatown

FordTotten

L‘EnfantPlaza

StadiumArmory

Shaw-Howard Univ.

Columbia Heights

Takoma

Forest Glen

UnionStation

FederalCenter

SW

CapitolSouth

PotomacAve

BenningRoad

CapitolHeights

AddisonRoad

MorganBlvd

LargoTownCenter

Congress Heights

National Airport

Pentagon

KingStreet

Smithsonian

Woodley Park Zoo

Comprising 165 kilometres of rail track and

a total of 84 stations, the Washington DC

Metrorail system is the second largest in the

USA. The system services a population of

3.5 million within the District of Columbia

and surrounding counties within Maryland

and Virginia—covering an area of nearly

4,000 square kilometres.

With roughly 275,000 people passing

through the turnstiles of the metro on a

daily basis, the issue of public safety is very

important. This is particularly so for the

underground sections of the metro system,

which comprise almost half the rail track

distance and an even higher proportion of

underground stations. Each of the metro’s

five lines has underground sections, with

the deepest station being Forest Glen on

the ‘Red’ line, 60 metres (21 stories) below

the ground.

Safety communications measures within

the metro include two-way radio contact

between the train operator and operations

control centre, and hotlines from the

operations control centre to the police and

fire departments. The purpose of these is to

ensure rapid or immediate response from

emergency services in the event they are

needed—and they depend on reliable

wireless communications. The wireless

emergency communications system in

the Washington Metro is a dedicated

dual band 400/800 MHz system,

as required by the public

safety standards in the

Washington DC area.

In support of emergency

communications within the

newest section of tunnel—

the eastern section of the

‘Blue’ line extension to Largo

Town in Maryland—Radio

Frequency Systems is supply-

ing optimized smooth wall

radiating cable technology. The

RADIAFLEX RAY 114-50JFLB (1-1/4 inch)

cable is being supplied in lengths of up to

750 metres to provide coverage for 15 kilo-

metres of new tunnel.

According to Ron Dorst, RFS Vice

President of Americas Wireless Distributed

Communication Systems, RFS worked

closely with the project’s system integrator

to determine the optimum cable to meet

the specific design requirements of the

RFS cable for Washington MetroThe emergency communications system of a key extension of the massiveWashington Metro is brought on air using smooth wall radiating cabletechnology from RFS.

The RADIAFLEX RAY series of radiating

cables for wireless coverage in tunnels and

buildings are smooth wall cables with inner

conductor, foam dielectric, copper strip

outer, and cable jacket. Unlike traditional

corrugated radiating cable that is fabricated

by milling coaxial cable, smooth wall

radiating cable is punched to create specific

‘antenna’ patterns that radiate in transverse

mode along the length of the cable.

The outer conductor apertures (or horizontal

slots) of the RAY series comprise groups

of ‘slope slots’ at short intervals. These

allow RF power to flow towards the

receiving mobile antenna, thereby

lowering the overall coupling loss of the

RF distribution system.

Radiat ingmode advantage

project. “For the particular frequency range

being used—400/800 MHz—and the

long cable lengths, the RAY 114B is the

optimum choice,”said Dorst. “Its superior

performance includes minimized insertion

loss and coupling loss.”

Dorst explained that the RAY 114B cable is

a modified form of RFS’s RAY 114 cable,

and has been developed especially for the

US market, where stop band requirements

(approximately 318 MHz and multiples) are

unique in comparison with other parts of

the world (approximately 270 MHz and

multiples). “This means that there are no

adverse effects of the stop bands on the

safety system,” he said.

9C O N F I N E D C O V E R A G EN E T W O R K O P T I M I Z A T I O N

studying base station parameters and

the requirements for co-located GSM

900/1800 sites. Hamed acknowledges that

they are looking at a great number of

upgrade options, particularly the use of

dualband antennas.

Ongoing relationshipSyriaTel has enjoyed an ongoing relation-

ship with RFS over the past few years.

“Since the beginning, it has been a very

good relationship from a technical,

commercial and personal point of view,”

says Nader Kalai, Chief Executive Officer

of SyriaTel.

This is largely through the establishment of

the RFS Middle East office in Dubai, headed

by Martin Dirnberger, supported by the

unstinted efforts of RFS’s resident consultant

in Damascus. “We prefer to deal with

companies with such formation; it makes it

more easy and convenient to us,” says

Kalai. “It is definitely more effective to

discuss current issues face to face and to

receive quick answers to our questions.”

In concert with the ongoing deployment

of base stations, RFS has provided

multiple shipments of CELLFLEX cable

and accessories to SyriaTel over the past

three years, at an average of one every

four to six weeks—the most recent in

July 2003.

SyriaTel’s cellular base stations. According

to SyriaTel’s Technical Director, Imad

Hamed, SyriaTel became involved with RFS

when it became clear that RFS was a leader

in wireless technology. “RFS has supplied

100 per cent of feeder cable for our base

stations, and is also one of SyriaTel’s two

cellular antenna suppliers,” says Hamed.

Demand risingAs of July 2003, the number of SyriaTel

subscribers was at 320,000, with that

number expected to more than double by

the end of the year. As SyriaTel is one of two

operators sharing roughly 50 per cent of

the market, this will take the projected

cellular penetration for Syria to greater than

eight per cent by the end of 2003. In order

to accommodate this upsurge in demand,

the operator is already planning to overlay

GSM 1800 MHz services.

“Our GSM 900 service is restricted to a

bandwidth of just 6.4 MHz, which is very

limiting from a capacity point of view,” says

Hamed. “We’re more or less obliged to

introduce the 1800 MHz service to meet

the demand. This is particularly the case in

the big cities, such as Damascus and

Aleppo, where densification is very high

and the spectrum is simply not sufficient.”

Currently, SyriaTel is still in the first phase of

GSM 1800 deployment, with engineers

Just over four years ago, the Middle-Eastern

nation of Syria had a waiting list of around

two million families for fixed line telephone

services. The state-owned Syrian Telecom-

munications Establishment (STE) has been

allocating significant resources to meet this

demand over the last decade or so;

however, the introduction of cellular

services in 2000 has also contributed

enormously to the telecommunications

growth in the country.

Following a successful trial period of global

system for mobile communications (GSM)

900 MHz services, during which the STE

supervised Syria’s fledgling cellular network,

a build-operate-transfer agreement resulted

in SyriaTel emerging as the nation’s leading

GSM operator in February 2001. Since that

date, the SyriaTel cellular network has

grown to cover nearly 95 per cent of the

population—from Hasake in the north-

east, to the Mediterranean coastal towns,

to the major cities of Aleppo in the north

and Damascus in the south, plus most of

the major inter-city roads.

Radio Frequency Systems was involved with

Syria’s cellular network at its inception, and

has supplied CELLFLEX foam-dielectric

flexible feeder cable for every one of

Broadcast beginningsUntil recently, Taiwan’s broadcasting industry

consisted of three commercial terrestrial TV

broadcasters providing analogue VHF-H

services: Taiwan Television (TTV), China

Television Company (CTV) and China

Television System (CTS). They were joined,

in 1997, by a new VHF commercial

broadcaster, Formosa Television (FTV) and

then, in 1998, by a publicly-owned

broadcaster, Public Television Service (PTS)

in the UHF band.

The analogue TV broadcasters generally

operated their transmission stations

separately, utilizing 6-MHz bandwidth

channels based on the US ‘national

television system committee’ (NTSC)

analogue TV standard. As time progressed,

however, there were mounting business

challenges: including repercussions from

the worldwide economic slowdown, and

increasingly strong competition from the

operators of satellite and cable TV.

Taiwan’s TV companies were soon looking

to new services and a way to revitalize the

industry—for many, the answer was DTV.

When the Taiwan government ruled that all

terrestrial TV stations were required to

commence digital services before the end

of 2001, it was largely welcomed by the

broadcasters. Despite the requirement to

invest heavily in new infrastructure, digital

TV was seen as a means to bring free-to-air

services into the modern age.

TTV’s Engineering Department Manager,

Sheng-Fu Chung, summarizes the benefits:

“DTV will mean that broadcasters can add

more programs (one analogue channel can

be used for four digital channels) and there

is better quality reception, image and

sound. While the transition period is

certainly difficult for all the terrestrial

stations, DTV will help all broadcasters

develop better profit-making businesses

and should help us to win over greater

audiences.”

The implementation of digital television

(DTV) services is soon to become a

nation-wide reality in Taiwan. At present,

the island’s five ‘free-to-air’ TV broadcasters

are making rapid progress in rolling-out

their network infrastructure. When

completed, Taiwan will be able to boast

some of the most advanced TV

broadcasting services in the Asia Pacific

region.

The achievements to-date have been

significant. Taiwan’s broadcasters have had

to contend with many challenges: from

economic uncertainty and intense

competition, to the need to provide

comprehensive coverage over a mountainous

and densely-populated island. These issues

are being overcome and, with the help of

Radio Frequency Systems, the benefits of

digital are becoming increasingly clear to

the island’s 22 million inhabitants.

Television broadcasting is poised to enter an exciting new era in Taiwan,as the process of digitization accelerates.

1110 C E L L U L A R

As the SyriaTel cellular networkexpands and evolves to meetSyrian subscriber demand, RFScontinues to play an importantsupport role through the supply ofkey wireless infrastructure.

Ce l lu lar on the r isein Syr ia

D T V D E P L O Y M E N T

DTV c l imbs mountains in Taiwan

Despite the rain, a site crew work to install

a RFS 6-bay broadband antenna on the PTS

tower at Hua Lien.

SyriaTel CEO, Nader Kalai: “ … it has been a very good relationship from a technical,commercial and personal point of view.”

supplied only an antenna at first.

But the broadcaster was very

happy with the solution, and

soon other people wanted

to come on air at the

same site—now we’re

talking about providing

combiners,” says Franke.

Huang at PTS believes that it is important

that the combiners be carefully designed to

ensure they provide a cost-effective overall

solution. “PTS has a preference for practical

combiners with an appropriate selection of

mask filters. In the end it requires an

economic, compact and integrated channel

combiner for digital and analogue channels,

and is employing RFS balanced channel

combiners with adequate band-pass

filters,” says Huang.

Benefits of foresightAs far as RFS is concerned, there is more

involved than just supplying the equipment.

The planning of transmission sites requires

consideration of many factors to ensure

optimal coverage to the desired service

areas. “We work closely with the broad-

casters in order to come up with the best

technical solutions,” says Franke.

In a number of cases, the specific broad-

casting requirements have had a large

impact on the way the system is designed.

“Every location is different. When we were

asked to consider some extra transmitter

sites south of Taipei, we found that this

would affect the coverage requirements of

the Taipei antenna system. We stayed on

radiation patterns but, along with an

appropriate combining system, they allow

the broadcaster to use the same antenna

for transmitting both analogue and digital

television broadcasts.

“It is important to us that the antennas cover

all frequencies from channel 20 to 59, as well

as providing upper and lower redundant

antenna systems. Because PTS uses UHF for

both analogue and digital TV services and

shares some sites with other broadcasters,

it is therefore making efforts to realize

wide-band common antenna systems. As a

result, PTS is integrating combiners with

broadband antennas in all DTV sites,” says

Chin-chang Huang, Transmission Section

Manager at PTS’s Engineering Department.

Broadcasters are also increasingly turning

to multi-channel combiners in their roll-out

of DTV systems. According to Norm Franke,

RFS Broadcast Sales Manager in Asia,

consolidation of equipment at broadcasting

sites is driving a strong need for combining

technology. “At three sites at least, we have

supplied directional waveguide channel

combiners. In one particular case, we

13

Setting the standardIn 1998, a formal decision was made for

Taiwan to adopt the US ‘advanced

television systems committee’ (ASTC)

digital standard. Based on 8-vestigial side-

band (8-VSB) technology, ATSC appeared

at the time to be a logical choice, given

its ready application to 6-MHz channels

and the NTSC standard being used for

analogue TV.

Before broadcasters began implementing

the new system, a two-year cooperative

trial was initiated using a pilot DTV station

at the Chu Tsu Shan site in Taipei.

Constructed in June 2000 by NEC Japan,

with an antenna from RFS, the purpose of

the pilot station was to allow all terrestrial

broadcasters to carry out extensive DTV

engineering tests.

According to TTV’s Chung, experiments

revealed that the ATSC DTV standard did

not fully meet the requirements of the

Taiwanese broadcasters. Although 8-VSB

technology allows for a larger coverage

area, it is not as well suited when there are

multi-path interference problems. “This is

especially significant, given Taiwan’s

mountainous terrain and high buildings in

the cities. In particular, the pilot site

revealed that indoor reception was not

satisfactory for our needs,” says Chung.

Consequently, Taiwan’s broadcasters began

to seriously consider the alternative

European ‘digital video broadcasting-

terrestrial’ (DVB-T) standard, based on coded

orthogonal frequency division multiplex

(COFDM) technology. Promising superior

performance for multi-path interference, as

well as allowing the establishment of

‘single-frequency networks’ (SFN)—in

which more than one transmitting site may

service the same coverage area—the new

standard was brought to the test.

“After changing the pilot station

equipment from 8-VSB to DVB-T devices,

it was found that the problem of multi-path

interference was largely solved,” says

Chung. By the end of June 2001, Taiwan

had reversed its original decision and

adopted the DVB-T standard.

12 D T V D E P L O Y M E N T

the same mountain, but we decided to

change the shape and size of the antenna

so that the beamwidth was larger. In the end

we got the system to pump power to the

bottom of the mountain, rather than all the

way out to the horizon,” says Franke.

For Bruce McIntyre, Broadcast Installation

Supervisor for RFS, consideration of

Taiwan’s mountains doesn’t end at the

equipment-design process. Throughout the

DTV roll-outs, McIntyre has worked long

days dismantling old antenna systems and

installing, testing and commissioning the

new ones. The location of many sites

means that logistics support is essential

to ensuring that equipment arrives in

one piece.

“The geographical layout of the island

means that there are sites up to 1000 metres

above sea-level—on the eastern seaboard,

many of the sites are perched right up on

escarpments. There can be access issues,

especially with the antenna arrays; some

antenna sections are up to ten metres long.

The roads leading up to them often have a

lot of tight bends, making it sometimes

difficult to get the equipment up to

the site—we’re overcoming it gradually,”

says McIntyre.

Island ‘on air’In the last 12 months, DTV developments

have further picked up pace and there is a

new focus on rolling out individual

networks. CTV and CTS are aiming to be

‘on air’ throughout the whole island by the

end of 2003, and TTV is close behind. PTS is

working on construction of a SFN in the

south of Taiwan, in efforts to bring its

programs to a wider audience, including

commuters on the municipal transportation

system in Kaohsiung.

While Taiwan’s broadcasters have had to

face many challenges, the implementation

of DTV is on-track. Close cooperation and

good communications between all parties

—from the broadcasters to site crews, RFS

and other key infrastructure providers—

have been instrumental to achieving this.

The end result is that, as 2004 approaches,

Taiwanese people will be able to witness

the fruits of digitally-enhanced TV—

an explosion in high-quality viewing

options everywhere, from the mountains

to the sea.

Digital’s first stepsWith the standard confirmed, each

broadcaster was allocated two adjacent

UHF channels to cover the island. The first

step involved a consortium of broadcasters:

TTV, CTV and CTS. Each took responsibility

for setting up one of three strategically-

important sites from which all would later

transmit combined services. These first sites

were set up on the island’s west coast,

where the majority of Taiwan’s population

live, near the cities of Taipei, Kaohsiung and

Taichung City.

It was not long, however, before all

broadcasters were involved in sharing

transmitter sites, while taking turns at

running what was becoming a nation-wide

network. DTV infrastructure was soon

being installed at four major sites on the

west coast and three on the more sparsely

populated east-coast. By May 2002, all five

TV companies were providing digital

services through the shared infrastructure

in the western part of the island.

These cooperative developments were new

in Taiwan—before the DTV implementation,

there was very little infrastructure sharing

between the terrestrial broadcasters. But

with fierce competition from cable TV in the

last three years, the combined approach

has enabled broadcasters to meet their DTV

transmission obligations sooner with less

initial investment. Additionally, more

infrastructure would be in place by the

time Taiwanese people started purchasing

the DTV-enabling ‘digital set top boxes’ in

large numbers.

Broad perspectiveBehind the rollouts has been the need to

contend with important infrastructure issues.

The first of these was the requirement at

each site to provide a suitable antenna

system. As a broadcast system designer, RFS

has been heavily involved in this process,

and has provided wireless solutions for

11 out of the 13 new DTV antenna systems

being installed in Taiwan, including the

pilot station.

For PTS, which is implementing RFS 6-bay

directional antennas and multi-channel

combiners at two of its sites, the use of

broadband antennas is essential. Not only

do they provide great flexibility in shaping

RFS’s experience in Taiwan extends back many years. Here, equipment

is unpacked for an analogue TV transmission site in 1995.

The RFS antenna is lifted by

crane at TTV’s Hou Yen Shan

tower near the city of San Yi.

The island-continent of Australia is an

immense, yet increasingly well-connected

land. From the modern metropolitan and

regional centres to the remote ‘outback’

communities, people are gaining tangible

benefits from ubiquitous access to wireless

services. Behind the latest achievements are

advanced broadcast and communications

networks, built in no small part with

the technology and expertise of Radio

Frequency Systems.

Carriers for a continentOvercoming the tyranny of distance has

long been a challenge in Australia. Often

referred to as ‘the wide brown land’, the

world’s sixth largest country is flat, arid and

inhospitable through much of its area, with

its 19 million people concentrated in

coastal regions. Furthermore, the physical

isolation of the land mass meant that it was

the last inhabited continent to be

discovered by Europeans. Since then,

explorers, settlers and immigrants have

worked to build connecting infrastructure

across Australia’s great expanses, turning

a once isolated colonial outpost into a

modern unified nation.

Wireless communications have played an

instrumental, albeit fairly recent, part in the

process of transforming Australia. It all

began when the government-owned

telecommunications body, Telecom

Australia, launched the first public

automatic mobile phone system in 1981,

and the first cellular network—utilizing the

advanced mobile phone system (AMPS)—

six years later. In the early nineties, partial

privatization began: Telecom became Telstra,

and was shortly joined by competing carriers,

Optus and Vodafone, in a push to roll-out

global system for mobile communications

(GSM) digital networks.

To ensure better coverage away from the

metropolitan areas, Telstra also launched

the first Australian code division multiple

access (CDMA) network in 1999, using

much of the original AMPS infrastructure.

New entrant Hutchison Telecommunications

(Orange) followed suit one year later with

its own CDMA network.

Today the success of mobile telephony in

Australia is evident—there are now 14 million

mobile phones, representing 70 per cent

of the population. While all carriers are

continuing to expand and refine their

networks to meet subscriber needs, attention

is now being drawn to the latest development

in the local cellular market—the launch of

third generation (3G) services.

New generation arrivesIn March 2003, Hutchison launched the

first Australian 3G network with great

fanfare in Sydney and Melbourne under the

brand name ‘3’. The system utilizes a

wideband CDMA radio access network to

provide a theoretical data rate of 384 kilo-

bits-per-second (kbps). Significantly, it adds

mobile video calling and mobile video

services to the traditional repertoire of

cellular phone capabilities.

Peter Walters, Marketing Manager RFS Asia

Pacific, explains the significance of the

launch: “Australia is playing a crucial role in

the pioneering developments of 3G. Japan

was the first in the world to implement it on

a serious commercial basis, and the next wave

has really been the concurrent Hutchison

roll-outs in Australia, Italy and the UK.”

Construction of the network infrastructure

by Ericsson Australia is ongoing, with

progressive expansion planned for all major

Australian cities. According to Walters, RFS

has been actively involved in the roll-out,

supplying remote-tilt antenna systems, along

1514

As third generation cellularnetworks arrive in Australia,communications services arecontinuing to reach further intothe country’s vast interior.

with components for in-building coverage.

“There’s been a big investment in infra-

structure to do it, but it’s an important

development—it shows that Australia is at the

forefront of cellular technology,” he says.

The acceptance by the public of the next

generation system in the next coming

months will be critical. Of the six companies

to bid a combined US$230 million for 3G

licenses in March 2001, Hutchison is the

only one to have implemented a working

wide-area system, and this system is in

its infancy.

Given uncertainty as to what standard

should spearhead the future of cellular, the

majority of carriers are instead deploying

interim solutions. Both Vodafone and

Optus are focusing on providing high

the people in the country,” says Walters. So

important is this need that the issue has,

in the last few years, become elevated

into public consciousness, influencing

the policy platforms of Australia’s leading

political parties.

At the heart of the matter is Telstra. The

government still retains 50.1 per cent

ownership of the telecommunications

giant, and full privatization is conditional on

Telstra providing adequate services in the

bush. Consequently, the company has

embarked on massive infrastructure

projects which include trials of CDMA

wireless local loop (WLL) equipment, and

upgrades of its digital radio concentrator

service (DCRS) to the latest high-capacity

radio concentrator (HCRC) technology.

RFS has supported both the original DCRS

and replacement HCRC point-to-multipoint

microwave systems. These essentially rely

on chains of antenna towers that pass radio

signals to and from properties, themselves

suitably equipped with antennas. “The goal

is to provide high quality telephone, fax and

broadband Internet access in the bush. RFS

is the major supplier from the RF side for

the program, especially with its ‘grid’

microwave antennas,” says Walters.

Even in regions beyond the reach of both

the fixed line and microwave linked networks,

RFS is working to provide wireless options.

“RFS is supplying L-band directional panel

antenna for use with the Optus MobileSat

satellite communications system,” says

Walters. “The high-gain antennas are very

portable and can be put in a

briefcase or hooked

up to a four-wheel drive. The direct satellite

link is particularly convenient in remote

parts of the interior, such as large cattle

stations and mining exploration areas.”

Spreading the messageThe emphasis on wireless for the bush,

however, is not limited to telecommuni-

cations. According to Kemel, RFS is working

to ensure that broadcast services are also

making their way across the country.

“Probably our biggest success so far has

been digital television (DTV). For several

years before the advent of the technology,

the engineering team was doing research

and development for the products required.

This meant that we were ready to implement

DTV in the major cities by 2001, and now

they’re broadening to a larger roll-out in

the country areas,” says Kemel.

Kemel attributes much of the success of

RFS in Australia to the ongoing efforts of its

Melbourne-based team. The combination

of local engineering expertise and a highly

professional approach, he believes, will be

crucial in enabling the company to adapt to

future changes in the wireless industry.

“Traditionally we have concentrated a lot

on the design and supply of products. Now

we are also focusing on the services

required for the projects

—from installation to

support and main-

tenance,” explains

Kemel. “We can

go further, and

not just for

Australia, but

globally.”

data-rates—with up to 100 kbps for the

recently launched ‘Vodafone Live!’—by

overlaying their GSM networks with the

global packet radio service (GPRS). For its

part, Telstra is providing enhanced

multimedia services with its 144 kbps

‘Mobile Loop’, made possible by an

upgrade of its existing CDMA network to

CDMA 2000 1xRTT.

Despite delays in rolling out 3G networks,

Australia’s cellular operators are maintaining

interest in the technology, especially the RF

systems that will enable the new services.

“RFS is providing equipment for universal

mobile telecommunications system (UMTS)

trials, currently underway. These include

trials involving a number of operators of

our advanced cellular antennas,” says

Martyn Kemel, RFS Regional Director, Asia

Pacific South.

Broadband for the bushWhile the advance of high-speed wireless

data systems continues unabated in Aus-

tralia’s cities, the challenges facing the

country’s rural areas, known collectively as

‘the bush’, are altogether different. Here,

the need has long been for basic voice and

data communications in zones where the

fixed-line telecommunications infrastructure

is inadequate, or even non-existent.

“Australia has a relatively small population

on a large piece of land; that’s an issue for the

wireless industry here. While the initial work

has concentrated on the cities, the Australian

government has made a commitment to

Wide brown land: wireless is providingsolutions for the vast Australian outback.

R E G I O N A L F O C U S

Wireless in a ‘widebrown land’

the six-channel combiner, the dual four-

channel offers two distinct advantages: the

ability for two independent sectors to be

controlled, and the provision of two

additional radio slots (having eight in total).

Small but reliableAnother product developed in response to

a specific Nextel requirement has been

bi-directional amplifiers (BDA) for in-building

applications. “Nextel wanted a small and

reliable BDA for medium-sized applications

such as parking garages and shopping

malls,” says Cullinan. “So they came to us

with all the specifications, including a budget,

and asked us whether we could do it.”

The resulting product range is the RFS

48000 series of BDAs, a cost-efficient

solution that maximizes capacity in the

coverage area while allowing centralized

base radios for better spectrum use and

control with lower maintenance costs. “The

48000 series is a very reliable product, and

is smaller than those we’ve produced in the

past. It fits Nextel’s requirements very well,”

says Cullinan.

At the heart of the relationship between

Nextel and RFS is a respect for the

engineering expertise of both parties.

“Both the Autotune combiner and the

BDAs were cooperative engineering efforts

between Nextel and RFS engineers,”

Cullinan emphasizes. “The Nextel system

engineers have visited the RFS laboratories

to assist with design parameters and

the explanation of network requirements.

Moreover, they are currently road testing

the new dual 4-channel AutoTune

combiner in their own labs. It’s rather

a unique relationship for us—but a very

effective one.”

Based in the eastern US state of Virginia,

Nextel Communications is one of the USA’s

top five national wireless carriers, and operates

the largest Motorola integrated digital

enhanced network (iDEN*) system in the

country. More than 11 million subscribers

enjoy the four-in-one iDEN wireless

communications service—comprising digital

cellular, Direct Connect* digital walkie-

talkie service, mobile text messaging, and

online connectivity—accessed from a single

integrated handset.

For the past two and a half years, Radio

Frequency Systems has been working closely

with Nextel as a key wireless solutions

provider. “Nextel realized that while they are

the expert in wireless networks and systems,

RFS is the expert in wireless components

and RF conditioning products,” says Dick

Cullinan, RFS Key Account Manager for

Nextel. “If we work together it’s to every-

body’s advantage; so our engineers and

Nextel’s engineers have been working in

concert on a number of different products.”

Collaborative developmentIn addition to significant quantities of cellular

antennas for Nextel’s 800-MHz, time division

multiple access (TDMA)-based iDEN Network,

RFS is an ongoing supplier of assorted RF

conditioning products. Of special note is

the RFS Autotune combiner (ATC860-6),

developed in association with Nextel Develop-

ment Engineering with the iDEN system in

view. Featuring continuous monitoring and

adjustment of frequency tuning, the Auto-

tune combiner allows multiple RF channels

to be broadcast from a single antenna while

maintaining very tight channel control.

According to Cullinan, the Autotune

combiner is compatible with both the new

Motorola Quad four-channel radios being

progressively introduced into Nextel’s

network, as well as single-channel Legacy

equipment, providing an enormous degree

of flexibility. “The Autotune combiner

allows Nextel to mix and match the Legacy

and Quad radios at the same site,” he says.

“For example, there might be four Quad

radios and two Legacy radios connected to

a six-channel Autotune combiner—this

means a total of 18 channels into the

one antenna.”

RFS is soon to launch a new version of the

Auto-Tune combiner—the ‘dual four-

channel’ unit (ATC860R-DUAL-4), a larger

configuration unit developed to provide

even greater flexibility. Similar in principle to

where you have additional wind force. So a

wind speed of 200 km/h can easily be

reached, and in many cases the antenna

requirements can be as high as 250 km/h.”

Stability under studyThe trials were conducted as part of a two

phase study during 2002 at the aero-

dynamic department of French research

and consulting centre, ‘Centre Scientifique

et Technique du Bâtiment’. When organiz-

ing the trials, RFS selected the Nantes facility

given its close proximity (70 kilometres

away) to the RFS microwave antenna

production facility in Trignac.

The subject of the trials was a single

‘ultra high performance’ RFS SlimLine

antenna (1 ft) and different ‘ultra high

performance’ RFS CompactLine antennas

(1, 2 and 4 ft ). Both product series are

designed to be lightweight and cost-

effective solutions, with the CompactLine

antennas employing a special feed system

and design to ensure especially low profile

and tower loading.

The antennas were tested both with and

without radio equipment, and were

attached to a pipe on a rotational table in

order to vary the angle of the wind.

Wojtkowiak summarises the results: “Each

antenna sustained the maximum wind

speed during several minutes for 12 angles

of wind, and no permanent damage or

deflections were observed. It was an

excellent opportunity to underline the

high mechanical performance of the

RFS antennas.”

Radio Frequency Systems has completed

wind-resistance trials of its single-polarized

CompactLine and SlimLine microwave an-

tennas. Conducted on behalf of British Tele-

com (BT) at a special wind tunnel facility in

Nantes, France, the trials proved the

capability of seven RFS 1-, 2- and 4-foot

antennas to meet their specified maximum

design wind- loading. In particular, the

trials demonstrated that the microwave

systems were able to withstand wind

speeds from all angles up to 250 kilometres

per hour (km/h).

“Large dish antennas in general are

designed for 200 km/h (125 mph),” says

Daniel Wojtkowiak, RFS Area Product

Manager Microwave Antenna Systems,

“but we have a simple option for an

upgrade to 250—which is our standard for

small size antennas. The trials demonstrat-

ed the stability of our antennas, under real

environmental conditions, up to this

specified survival wind speed of 250 km/h

(155 mph).”

Pressure on performanceA desire for greater certainty in the

mechanical performance of the RFS antennas

was the inspiration behind the recent trials.

The challenge for BT engineers was to

simulate the expected antenna wind-loading

as realistically as possible, and called for

wind tunnel testing at high speeds.

According to Wojtkowiak, reproducing

these high speeds is essential to demon-

strating the physical integrity

of the antenna system.

“When designing the

microwave antennas

it is necessary to

consider the potential

wind-loading, and

for that you need to

consider where they

are going to be used. For

example, in Ireland and the

UK, there is already a high wind speed just

at the ground level. Then you have to factor

that these large-sized radio link antennas

are usually installed on top of mountains,

17

RFS and Nextel f ind the r ight combinat ion

16

Recent wind trials of RFS solidmicrowave antennas in Francedemonstrate their inherentlyrobust design.

R F C O N D I T I O N I N G

* iDENTM is a trademark of Motorola;Direct ConnectSM is a service mark of

Nextel Communications.

A unique working relationshipbetween US wireless serviceprovider, Nextel Communications,and Radio Frequency Systems hasled to the cooperative develop-ment of the cutting-edge RFS Autotune combiners and a newrange of bi-directional amplifiers.

M I C R O W A V E

Lightweightantennas withstandthe winds

Of particular note will be the company’s

combiner technologies. Two units from

either end of the power scale will be on

display: RFS’s compact low power combiner,

which is optimised for the 20 to 250-Watt

range, plus the high-power RFS waveguide

filter module.

RFS will also exhibit an example broadband

UHF panel array, a type of antenna finding

wide application in DTV broadcasting. The

display will be complemented by a UHF slot

antenna, which is proving particularly

useful for temporary services during site

upgrade activities.

Other equipment on the RFS stand will include

a new range of digital audio broadcasting

(DAB) filters, the company’s Antenna System

Monitor, and RFS’s comprehensive range of

HELIFLEX flexible transmission lines.

With digital broadcasting on the rise in

Europe, Radio Frequency Systems will

display its comprehensive range of total

broadcast system solutions at the upcoming

IBC 2003 exhibition in Amsterdam.

“One of the key questions most television

broadcasters are facing is whether their

existing transmission site infrastructure will

support digital services,” said Hans-Peter

Quade, Head of Broadcast System Sales for

RFS in Europe, Middle-East, Africa and

India. “The answer is complex. Some

broadband antenna systems are capable of

accepting additional services without any

modification, many others will require

equipment upgrades.”

Over the past five years, RFS has completed

numerous digital television (DTV) network

upgrades across Europe, North America

and Asia Pacific. At IBC this September, RFS

will exhibit examples of the leading-edge

components used to realize these digital

broadcasting upgrades.

American audiences in the city of Dallas,

Texas, are increasingly benefiting from

enhanced digital television (DTV) services,

made possible by an impressive new

broadcast tower facility at Cedar Hill. These

viewing options are set to expand even

further, as leading US tower owner and

operator, Richland Towers, installs an

advanced UHF broadcast system on the

facility’s 498-metre tower. At the heart

of the solution is a state-of-the-art

antenna and combiner system from

Radio Frequency Systems, ensuring both

optimized and flexible coverage for future

broadcast services.

According to Tony Magris, Vice President of

Broadcast for RFS Americas, the prominent

location of Cedar Hill makes it a particularly

attractive site. “Many of the stations are

looking to move there, because of its

coverage over the Dallas area. There will be

a number of important services located at

this site,” he said.

The RF installation includes rigid line feeders,

an RFS 12-level, three-sided broadband

antenna array (supporting an 80-kW

average input), and a compact four-channel

UHF directional waveguide combiner. The

system will provide digital broadcast

19

The spread of RF coverage into confined areas

in the last few years has been dramatic.

Wireless distributed communication systems

are continuing to extend the realm of mobile

phone access deeper into the world’s

buildings, tunnels and mines. But as new

services arrive and coverage demands rise,

growing pressure is being put on the

existing RF infrastructure.

In the next issue of STAY CONNECTED, read

how Radio Frequency Systems is helping to

keep operators on course with the next

phase in indoor wireless solutions.

Wireless advances within

P R E V I E W STAY CONNECTED4th quarter 2003

New power for online catalogue

RFS presents DTV opt ions at IBC 2003

Dal las DTV r ises above the cedarsDal las DTV r ises above the cedars

Strong s igns atRuss ian expo

Visit RFS at IBC 200312 to 16 September, 2003

Stand 221, Hall 5, RAI Amsterdam

Customers can now obtain wireless

product information with greater

efficiency, thanks to a major interface

upgrade for the Radio Frequency Systems

‘WebXPress’ online catalogue. The key

development is an enhanced search facility,

allowing users to rapidly search a new

database index for specific information.

“Our e-Catalogue is significantly

improved—it is now fully searchable, not

only by product name or number, but

also by specifications and descriptions,”

said Jörg Springer, RFS Global Director of

Public Relations. The advanced new

The new RFS broadbandUHF antenna system will

be added to the 498-metretower at Cedar Hill in

Dallas, Texas, USA.

services for channels 36, 43, and adjacent

channels 45 and 46.

The new combiner has been specifically

designed to ensure operating flexibility, and

easy expansion of the combining system

with minimal disruption to existing services.

Blanking sections ingeniously incorporated

into the base waveguide allow new filters

for desired future channels to be easily

retrofitted into the combiner assembly,

when required.

I N T O U C H18

search capability combines the existing

‘Step Search’ parametric search with a new

‘Keyword Search’ function. In particular,

it allows use of ‘AND’, ‘NOT’ and ‘OR’

operators, while supporting the following

search methods: ‘whole word’, ‘partial

word’, ‘phrase’ and ‘named fields’.

“Most of the so-called industrial e-Catalogues

are just searchable ‘PDF’ versions of print

catalogues,” said Springer. “The RFS

catalogue, on the other hand, grants

access to the complete database of

products with an extremely flexible and

convenient front-end.”

The RFS Russia team at SVIAZ EXPO COMM 2003.

RFS has installed broadband antennasat multiple DTV sites to accommodatecombined analogue/digital services.

The telecommunications market in Russia

and many CIS-States continues to expand:

after 121 per cent growth during 2002, the

number of Russian subscribers is escalating

at similar rates in 2003, and is projected to

reach 30 million by the end of the year. Radio

Frequency Systems is playing a significant

part in this growth, and attracted a record

number of visitors to the RFS booth at the

SVIAZ EXPO COMM 2003 telecommuni-

cation fair, held in Moscow in May.

According to RFS Head of the Representative

Office Russia & CIS, Michael Schueler, the

participation of RFS at the SVIAZ EXPO

COMM 2003 could only be described in two

words: very exciting. “All Russian and many

CIS cellular operators visited our booth and

expressed keen interest in our products and

services,” Schueler said. “We look forward

to building relationships and potentially

working with them in the future.”

At SVIAZ EXPO COMM 2003, RFS presented

a wide range of advanced RF technologies,

including the company’s new CELLFLEX ‘A’

series high-performance feeder cable range,

and the world-renowned Optimizer pre-

mium-grade cellular antenna technology.

The Optimizer antennas, in particular,

attracted a deal of attention from visitors.

RFS has earned a reputation for excellence

within the booming CIS wireless market,

and has well-established relationships in

place with operators right across the

region. These include MobileTeleSystems

(MTS), Vimpelcom, MegaFon, Ukranian

Mobile Communications (UMC) and

Kyivstar, plus a range of smaller operators

across Russia, Ukraine, Kazakhstan,

Uzbekistan and Georgia.

R A D I O F R E Q U E N C Y S Y S T E M S

T h e C l e a r C h o i c e i n W i r e l e s s ™

Please visit us on the internet at http://www.rfsworld.com T h e C l e a r C h o i c e i n W i re l e s s ™

3rd quarter 2003

Tuning to the key of RF

RFS cable for Washington metro

Cellular on the rise in Syria

DTV climbs mountains in Taiwan

Wireless in a ‘wide brown land’

The Radio Frequency Systems Bulletin