Audio Quality (VHF-COM)on Aircrafts

Francisco ALMEIDA da Silva Cel Esp COM

March 17th, 2016

Listen …

Escute ...

Station A

Station B Station C

CLIMAX OPERATION

Climax or Multi-carrier systems are sometimes used for redundancy reasons, but mainly for large geographical ATC sectors or sectors with difficult propagation due to relief or mountains. In such cases, the VHF coverage for air-ground communications cannot be met with a single ground transmitter. For ground-to-air transmissions, several legs (actually 2 to 5 at maximum) meaning several ground transmitters are used simultaneously. Each leg transmits a signal within the same 25 kHz channel with a specific slight carrier offset. Those offsets are standardized in ICAO documents.

CLIMAX OPERATION

Coberturas em FL250

CLIMAX OPERATION

voo realizado

em 20/05/2015

Coberturas em FL250

Pilot opinion:

Quality 2/5, metalic

and echo

CLIMAX OPERATION

Reducing the number of

stations, improves the

communication quality,

because reduces the

audio components

cancelation.

data setor frequência nível de voo qualidade áudio posição19/10/2015 10S 133,05 FL370 4/5 OK OBGOV

19/10/2015 10P 124,70 FL370 4/5 OK OBGOV

19/10/2015 10S 133,05 FL370 4/5 OK ISURO

19/10/2015 10P 124,70 FL370 4/5 OK ISURO

19/10/2015 10S 133,05 FL370 3-4/5 metalizado NIBMO

19/10/2015 10P 124,70 FL370 3-4/5 metalizado NIBMO

19/10/2015 11P 124,50 FL370 4/5 OK NIBMO

19/10/2015 11P 124,50 FL370 3/5 metalizado MOLMO

19/10/2015 11P 124,50 FL370 3/5 metalizado NIMKI

19/10/2015 13P 124,30 FL370 4/5 OK NIMKI

19/10/2015 13P 124,30 FL370 3/5 metalizado entre NIMKI e MOMKO

19/10/2015 4P 128,05 FL370 3-4/5 metalizado/ruído de MOMKO até PABAV

19/10/2015 4P 128,05 FL370 2-3/5 metalizado entre PABAV e NIPKI

19/10/2015 1P 126,15 FL370 2/5 metalizado/eco NIPKI

19/10/2015 2P 123,35 FL370 2-3/5 metalizado/eco entre NIKPI E OPRUT

19/10/2015 1P 126,15 FL280 2-3/5 metalizado/eco MOXEP

15/12/2015 5P 124,20 FL380 3/5 metalizado entre RPR e SIDOV

15/12/2015 11P 124,50 FL380 3/5 metalizado/ruido entre NATIO e ISURO

15/12/2015 6P 128,30 FL360 1/5 ININTELIGIVEL UDIGI

13/01/2016 1S 127,20 FL270 3/5 metalizado/ruído ewntre VUMRV e UBRIR

14/01/2016 1P 126,15 FL360 2/5 metalizado/rui/eco entre VULER e EDNOT

16/01/2016 7S 125,05 de 4 a 1 ruido entre VUKEP e WELIN

16/01/2016 7P 123,75 de 4 a 1 ruido entre VUKEP e WELIN

23/01/2016 15P 126,75 FL390 1/5 ruido entre GAXUB e POSMU

31/01/2016 3P 126,8 FL360 1-2/5 metalizado/ruido entre LONAL e PUKTO

20/02/2016 15 127,30 FL380 3/5 metalizado/ruído entre POSMU e CNF

22/02/2016 3S 128,50 FL320 5/5 OK entre RCL e RPR

22/02/2016 3S 128,50 FL320 4/5 eco RPR

22/02/2016 3P 126,80 FL320 3/5 eco RPR

22/02/2016 5P 124,20 FL320 2-3/5 metalizado entre RPR e CORVO

22/02/2016 7P 123,75 FL320 2-3/5 metalizado/ruído entre CORVO e VALAP

22/02/2016 4P 128,05 3/5 metalizado/ruído entre MOMKO e MOPNI

CLIMAX16/02/16

UBERABASÃO ROQUECAMPINAS

CLIMAX OTIMIZADO 22/02/16

SÃO ROQUECAMPINAS

S3 S3

CLIMAX OPERATION

CLIMAX OPERATION

Volume III part II 2.3.2.4 Note 2:

When using offset carrier systems, receiver performance may becomedegraded when receiving two or more similar strength offset carrier signals.Caution is therefore advised with the implementation of offset carrier systems.

Para equipamentos de bordo:

2.3.2.5 – Adjacent channel rejection:

b) 25 kHz channel spacing environment: 50dB or more at +/- 25kHz with respect to

the assigned frequency and 40 dB or more at +/- 17kHz.

2.3.2.6 – Recommedation:

Whenever practicable, the receiving system should ensure an effective adjacent

channel rejection characteristic of 60 dB or more at plus or minus 25 kHz, 50 kHz and

100 kHz from the assigned frequency for receiving systems intended to operate in

channel spacing environments of 25 kHz, 50 kHz and 100 kHz, respectively.

CLIMAX OPERATION

ESPECIFICAÇÃO EUROCAE ED-23C

CLIMAX OPERATION

CLIMAX OPERATION

The two carries and sidebands are in the effective BW of the aircraft radio.

[ F0 – 5 kHz ] and [ F0 + 5 kHz ]

CLIMAX OPERATION

PROBLEMA:

LSB cut off

This configuration is no longer adopted by DECEA

PROBLEMA:

USB cut off

CLIMAX OPERATION

[ F0 – 7.3 kHz ] [ F0 ] [ F0 + 7.3 kHz ]

[ F0 – 7.3 kHz ] [ F0 ] [ F0 + 7.3 kHz ]

The three carries and sidebands are in the effective BW of the aircraft radio.

CLIMAX OPERATION

[ F0 – 7,5 kHz ] [ F0 – 2,5 kHz ] [ F0 + 2,5 kHz ] [ F0 + 7,5 kHz ]

The four carries and sidebands are in the effective BW of the aircraft radio, and there is no superposition of sidebands.

CLIMAX OPERATION

[ F0 – 4 kHz ] [ F0 – 8 kHz ] [ F0 + 4 kHz ] [ F0 + 8 kHz ]

PROBLEMA:

LSB cut off

PROBLEMA:

USB cut off

PROBLEMA:

Sidebands superposition

This configuration is no longer adopted by DECEA

CLIMAX OPERATION

This configuration is highly undisareable

[ F0 – 4 kHz ] [ F0 – 8 kHz ] [ F0 ] [ F0 + 4 kHz ] [ F0 + 8 kHz ]

Configuração muito deficiente, não é usada mais usada em APP/ACC

PROBLEMA:

Carries in the cut off limit and suprposition of all sidebands

[ F0 – 4 kHz ] [ F0 – 8 kHz ] [ F0 ] [ F0 + 4 kHz ] [ F0 + 8 kHz ]

CLIMAX OPERATION

PARK AIR RADIO

CLIMAX OPERATION

CLIMAX OPERATION

Channeling

CLIMAX OPERATION

CLIMAX OPERATION

TASK FORCE CLIMAX (GT CLIMAX)

Fase 1 – offset configurationChange the offset values to conforme to ANNEX 10 – VOL III specifications;

Fase 2 – number of stationsDimensioning of stations number in climax for each sector, limiting toadequate for a good coverage; and

3ª Fase – Integration between STVD and Voice Switch:TF is elaborating specifications for integration of STVD (ATECH) and VoiceSwitch (SITTI).

CLIMAX OPERATION

Technical Branch - Deputy

SDTE/DECEA

Francisco Almeida da Silva Cel Esp Com

E-mail: asdte@decea.gov.br

Phone: +55 21 2101-6461

Cel: +55 21 98552-0829