This receiver, originally used at the UK National Physical Laboratory for measurements on the ionosphere, was employed by Robert Watson-Watt (1892-1973) in the first convincing demonstration of radar. The experiment took place in a field in Northamptonshire on 26 February 1935.

While a Heyford bomber flew to and fro at 1524 m (5000 ft) in the beam from the BBC Empire Short-Wave transmitter at nearby Daventry, Watson-Watt studied a flickering trace on a cathode-ray tube. Deflections of the trace when the bomber was 13 km (8 miles) away confirmed his belief that distant aircraft could be detected from their radio reflections.

This receiver, originally used at the UK National Physical Laboratory for measurements on the ionosphere, was employed by Robert Watson-Watt (1892-1973) in the first convincing demonstration of radar. The experiment took place in a field in Northamptonshire on 26 February 1935.

While a Heyford bomber flew to and fro at 1524 m (5000 ft) in the beam from the BBC Empire Short-Wave transmitter at nearby Daventry, Watson-Watt studied a flickering trace on a cathode-ray tube. Deflections of the trace when the bomber was 13 km (8 miles) away confirmed his belief that distant aircraft could be detected from their radio reflections.

This receiver, originally used at the UK National Physical Laboratory for measurements on the ionosphere, was employed by Robert Watson-Watt (1892-1973) in the first convincing demonstration of radar. The experiment took place in a field in Northamptonshire on 26 February 1935.

While a Heyford bomber flew to and fro at 1524 m (5000 ft) in the beam from the BBC Empire Short-Wave transmitter at nearby Daventry, Watson-Watt studied a flickering trace on a cathode-ray tube. Deflections of the trace when the bomber was 13 km (8 miles) away confirmed his belief that distant aircraft could be detected from their radio reflections.

This receiver, originally used at the UK National Physical Laboratory for measurements on the ionosphere, was employed by Robert Watson-Watt (1892-1973) in the first convincing demonstration of radar. The experiment took place in a field in Northamptonshire on 26 February 1935.

While a Heyford bomber flew to and fro at 1524 m (5000 ft) in the beam from the BBC Empire Short-Wave transmitter at nearby Daventry, Watson-Watt studied a flickering trace on a cathode-ray tube. Deflections of the trace when the bomber was 13 km (8 miles) away confirmed his belief that distant aircraft could be detected from their radio reflections.

This receiver, originally used at the UK National Physical Laboratory for measurements on the ionosphere, was employed by Robert Watson-Watt (1892-1973) in the first convincing demonstration of radar. The experiment took place in a field in Northamptonshire on 26 February 1935.

While a Heyford bomber flew to and fro at 1524 m (5000 ft) in the beam from the BBC Empire Short-Wave transmitter at nearby Daventry, Watson-Watt studied a flickering trace on a cathode-ray tube. Deflections of the trace when the bomber was 13 km (8 miles) away confirmed his belief that distant aircraft could be detected from their radio reflections.

This receiver, originally used at the UK National Physical Laboratory for measurements on the ionosphere, was employed by Robert Watson-Watt (1892-1973) in the first convincing demonstration of radar. The experiment took place in a field in Northamptonshire on 26 February 1935.

While a Heyford bomber flew to and fro at 1524 m (5000 ft) in the beam from the BBC Empire Short-Wave transmitter at nearby Daventry, Watson-Watt studied a flickering trace on a cathode-ray tube. Deflections of the trace when the bomber was 13 km (8 miles) away confirmed his belief that distant aircraft could be detected from their radio reflections.

This receiver, originally used at the UK National Physical Laboratory for measurements on the ionosphere, was employed by Robert Watson-Watt (1892-1973) in the first convincing demonstration of radar. The experiment took place in a field in Northamptonshire on 26 February 1935.

While a Heyford bomber flew to and fro at 1524 m (5000 ft) in the beam from the BBC Empire Short-Wave transmitter at nearby Daventry, Watson-Watt studied a flickering trace on a cathode-ray tube. Deflections of the trace when the bomber was 13 km (8 miles) away confirmed his belief that distant aircraft could be detected from their radio reflections.

This receiver, originally used at the UK National Physical Laboratory for measurements on the ionosphere, was employed by Robert Watson-Watt (1892-1973) in the first convincing demonstration of radar. The experiment took place in a field in Northamptonshire on 26 February 1935.

While a Heyford bomber flew to and fro at 1524 m (5000 ft) in the beam from the BBC Empire Short-Wave transmitter at nearby Daventry, Watson-Watt studied a flickering trace on a cathode-ray tube. Deflections of the trace when the bomber was 13 km (8 miles) away confirmed his belief that distant aircraft could be detected from their radio reflections.

This receiver, originally used at the UK National Physical Laboratory for measurements on the ionosphere, was employed by Robert Watson-Watt (1892-1973) in the first convincing demonstration of radar.

The experiment took place in a field in Northamptonshire on 26 February 1935. While a Heyford bomber flew to and fro at 1524 m (5000 ft) in the beam from the BBC Empire Short-Wave transmitter at nearby Daventry, Watson-Watt studied a flickering trace on a cathode-ray tube. Deflections of the trace when the bomber was 13 km (8 miles) away confirmed his belief that distant aircraft could be detected from their radio reflections.