MR Ratcliffe (Postbag, August 11) expressed his opinion about the relative weight given to various aspects of the story of radar in my exhibition The Magic Ear.

I realised early in the planning stages that, with limited space and money, it was not realistic to attempt a comprehensive account of the technology. I believed however that, provided the resulting choices were clearly spelled out, they would be understood and accepted by most visitors.

Accordingly, the opening panel of the display states: "TRE worked mainly for the Air Force. The main focus of this exhibition is therefore on the air war. But it describes the vital role played by the Army and Navy in the evolution of the technology and the development of radar in other countries before and during World War Two".

Later panels show:

n How two officers from the Army's Signals Experimental Establishment almost invented radar in 1931;

n That an Army 'cell' working alongside the RAF team at Bawdsey helped devise the coastal defence and Chain Home Low defensive networks;

n The invention of gun-laying and searchlight radar;

n The use of IFF techniques by Army gunners to avoid shelling friendly aircraft;

n The Army's crucial contribution to the 'spoofs' which helped ensure the success of the D-Day landing.

The exhibition (which is not meant to be 'parochial' but has been specifically designed to tour to other museums) gives roughly similar space to the work of the Navy, not least in commissioning the cavity magnetron - which made airborne radar possible - and in helping win the Battle of the Atlantic.

I am sorry if Mr Ratcliffe thinks my priorities are wrong but he cannot reasonably argue they are not explicitly signalled and carefully explained.

David Robertson, organiser of The Magic Ear, High Grove Barn, Croft Bank, West Malvern.