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vanjast · 10-23-08, 02:21 AM

http://en.wikipedia.org/wiki/Magnetron

The UK invention that made portable radar a reality. Although radar was already known to both sides, the equipment was still massive and non portable. This UK invention (wiki-link) and the USA's WW2 productivity capabilities was one of the main technological contributors to 'vinning ze Var'

Read somewhere that the 'Brits' were against donating one of these to the Americans (Allies WW2 Technological Exchange Agreement), but Winston Churchill over-ruled them, and in a 'return convoy' a small box not much bigger than a shoe box, travelled on a ship with tight security. It was said that the Americans were 'blown away' when they saw the device - and very soon miniature portable radar sets appeared on most military 'vehicles'.

Essentially all high powered radar systems are 'pulsed', or they'd pop within a second. Nowdays there are many types of radar, using the microchip to do signal conditioning, etc to pick out the relevant info from the mess.
Most radars use a single frequency (limitations of the magnetron) where the frequency has known effects in the atmosphere
- High frequency is absorbed more readily and has shorter effective range, and better target definition. Smaller aerials, more line of site operation.
- Lower Frequency stuff has longer ranges and is 'bent'/'bounced' by the atmosphere so has the capability to look over the horizon. It has poorer target definition. Larger aerials.

You can see the 'similarities/opposites' in Sonar where a high frequency ping is 'bent' more easily than a lower frequency at greater depths or through thermal layers. Modern day sonars also use a 'Chirp' method, which is just a range of frequencies transmitted (Frequency sweep). To get anything intelligable from this, one needs processing power of DSP microchips of something similar.

My short story this morning... :rotfl:

10-23-08, 02:21 AM	#52
vanjast Sea Lord Join Date: Jun 2006 Location: Somewhere else now Posts: 1,740 Downloads: 825 Uploads: 4	http://en.wikipedia.org/wiki/Magnetron The UK invention that made portable radar a reality. Although radar was already known to both sides, the equipment was still massive and non portable. This UK invention (wiki-link) and the USA's WW2 productivity capabilities was one of the main technological contributors to 'vinning ze Var' Read somewhere that the 'Brits' were against donating one of these to the Americans (Allies WW2 Technological Exchange Agreement), but Winston Churchill over-ruled them, and in a 'return convoy' a small box not much bigger than a shoe box, travelled on a ship with tight security. It was said that the Americans were 'blown away' when they saw the device - and very soon miniature portable radar sets appeared on most military 'vehicles'. Essentially all high powered radar systems are 'pulsed', or they'd pop within a second. Nowdays there are many types of radar, using the microchip to do signal conditioning, etc to pick out the relevant info from the mess. Most radars use a single frequency (limitations of the magnetron) where the frequency has known effects in the atmosphere - High frequency is absorbed more readily and has shorter effective range, and better target definition. Smaller aerials, more line of site operation. - Lower Frequency stuff has longer ranges and is 'bent'/'bounced' by the atmosphere so has the capability to look over the horizon. It has poorer target definition. Larger aerials. You can see the 'similarities/opposites' in Sonar where a high frequency ping is 'bent' more easily than a lower frequency at greater depths or through thermal layers. Modern day sonars also use a 'Chirp' method, which is just a range of frequencies transmitted (Frequency sweep). To get anything intelligable from this, one needs processing power of DSP microchips of something similar. My short story this morning... :rotfl: