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Input by Robin Webb

The SECAR Secondary Surveillance Radar was a joint development by Marconi and Thompson-CSF (T-CSF) of France. Marconi designed and built the Interrogator/Responser and T-SCF the decoding system. This was a manual decoder, i.e. each aircraft on the display had to be actively decoded if the SSR code was unknown. This involved the positioning of a marker over the target and then the code would be displayed on the SSR control. Passive decoding, as it was known, was used when the SSR code was known in advance by the controller and set on thumbwheel switches. The aircraft with the known code would show up on the display as a number of bars; no symbol generation being used at that time.

The writer believes the only SECAR systems sold were to Eurocontrol (then in its infancy) and installed in the Republic of Ireland. This may need confirmation though.

During the mid sixties a system was demonstrated in Russia at the airport in Moscow. We were still in the cold war era so this was quite a challenge, especially for those who had to go and install it. However, a sale didn't come about.

Installing the "SECAR" antenna at the 1965 Paris Air Show (Picture, R.A. Webb)

Setting up the "SECAR" Interrogator/Responsor at the 1965 Paris Air Show (Picture, R.A. Webb)

In the picture, Bruce Woodcock (reading the instructions!) and an unidentified person.

Secar Demonstration at Rivenhall 1965

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