ALLISS

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ALLISS antenna as viewed underneath

ALLISS is a rotatable antenna system for high power shortwave radio broadcasting.

Contents

0.1 Technology FAQ
0.2 Other important ALLISS advantages
0.3 Cost per module
0.4 Versions of ALLISS modules
0.5 Transmitter
0.6 Antennas (high band)
0.7 Antennas (low band)
0.8 Relay stations with ALLISS modules

1 See also
2 External links

Technology FAQ

ALLISS allows a broadcaster to change the following shortwave transmission parameters

direction (azimuths from 0 to 360 degrees)
broadcast frequency
antenna configuration (ie: HR 4/4/1 -> HR 6/4/1)

at any time.

All of these transmission changes can take effect in as little as 5 minutes. This flexibility can allow a broacaster to redirect the entire shortwave transmission network to a strategically important target area in as little as 15 minutes.

Other important ALLISS advantages

Modular construction

ALLISS relay stations can be built on a module by module basis.
An ALLISS module can start broadcasting as soon as construction is completed.

Higher RFI & EMF compatibility vs traditional relay stations

ALLISS modules can be geographically scattered for security and RFI exposure reasons.
Ironically, TDF did not pursue this option at Allouis or Issoudun — a technologial blow to French security.

Each ALLISS module is fully automated, so there is no need for technical staff. When there are 2-5 ALLISS modules scattered over several hundred square kilometers, a two person support staff is enough to keep the modules in operation year round (provided these modules are visited monthly for repair and maintenance).

Cost per module

Around US$10 million.

Some modules have been rumored to cost as much as US$15 million.
With 4 different module versions cost per module can vary by as much as US$5 million.
At least 30% of the cost of each module is related to the still exotic metallurgy and metalworking requirements needed to construct each module.
Because of the costly and complex metallurgy construction requirements, ALLISS technology is 'off limits' to many developing nations including even a few advanced nations in the developed world.

Versions of ALLISS modules

According to the current Thales brochure on ALLISS, there are 6 different versions of the ALLISS system. These versions are sorted by date of initial installation.

1995: Issoudun and Allouis, France
* Low Band Modes (HR) : 4/4, 4/3, 4/2, 2/4, 2/3, 2/2
* High Band Modes (HR) : 4/6, 4/4, 4/2, 2/6, 2/4
* Band coverage: 5.9 MHz to 26.1 MHz (10 modules)
* Band coverage: 5.9 MHz to 17.9 MHz (2 modules)

1997: Nauen-A, Germany
* Low Band Modes (HR) : 4/4, 2/2
* High Band Modes (HR) : 4/4
* 2 systems installed

1997: Nauen-B, Germany
* Low Band Modes (HR) : 4/4
* High Band Modes (HR) : 4/4
* 2 systems installed

2002: Al-Seela, Oman
* Low Band Modes (HR) : 4/4, 2/4, 4/2, 2/2
* High Band Modes (HR) : 4/4, 2/4, 4/2, 2/2
* 2 systems installed
* Band coverage: 5.9 MHz to 17.9 MHz

2003: China
* Low Band Modes (HR) : 4/4, 2/4, 4/2, 2/2
* High Band Modes (HR) : 4/4, 2/4, 4/2, 2/2
* Band coverage: 5.9 MHz to 26.1 MHz

Transmitter

Typically ALLISS modules possess a 500 kW polyphase shortwave transmitter.

Digital 'AM' type transmitters are preferred for their compactness, as opposed to 'push-pull' (Class-B) transmitters for ALLISS installations.
Essentally all 300 kW and 500 kW PDM, PSM, polyphase (4 x PDM) transmitters are preferred for structural reasons.
It is not customary to install a 300 kW transmitter in an ALLISS module, but such installations are possible.
TDF's Montsinnery Relay Station has 2 ALLISS modules installed, but without an installed shortwave transmitter. This same design arrangement is used by the BBC World Service Oman Relay Station Al-Seela.

Antennas (high band)

Three HRS array antennas types are available for broadcasting in the traditional shortwave broadcasting bands.

For tropical and lower frequency shortwave broadcasting

HR 4/2/1 (using low band antenna)
HR 2/4/1 (using low band antenna)
HR 2/2/1

For traditional shortwave broadcating

HR 4/2/1
HR 4/4/1

For highly directional shortwave broadcasting

HR 6/4/1
HR 6/2/1

The HRS 6/4/1 is not available for use in the 26 MHz band.

Antennas (low band)

One Low Band antenna exists for Tropical Band broadcasting. It takes up the entire back side the ALLISS module. This Low Band antenna counterbalances the primary transmission antennas used in traditional shortwave broadcasting.

Relay stations with ALLISS modules

Documentation format — Nation : Broadcaster : City (Modules, Date Sold)

France : TDF : Allouis (6 modules, 1995)
France : TDF : Issoudun (6 modules, 1996)
Germany : DW : Nauen (4 modules, 1997)
French Guiana : TDF : Montsinnery (2 modules, 1997)
Oman : BBCWS & VT Merlin : (2 modules, 2002)
China : SARFT : Xian(?) : (12 modules, 2005)

Total number of modules sold since 1989: 32

External links

ALLISS image gallery

http://cbc.am/alliss1.jpg
http://cbc.am/alliss2.jpg
http://cbc.am/alliss3.jpg
http://cbc.am/alliss4.jpg
http://cbc.am/alliss5.jpg
http://cbc.am/alliss6.jpg
http://cbc.am/alliss7.jpg
http://cbc.am/alliss8_Nauen_proto.jpg
http://cbc.am/alliss9_Nauen_proto_and_ALLISS.jpg
http://cbc.am/Thales_ALLISS_brochure.jpg
http://cbc.am/Thales_ALLISS_brochure_contents.jpg
[ALLISS web brochure]
[ALLISS press releases]

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