Talk:Proximity fuze

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Contents 1 Land Variants? 2 Misspelling 3 Bush? 4 How they found which vacuum tubes would survive the setback of firing from an artillery piece.

[edit] Land Variants?

Uh how would a proximity fuze of the type described here work on land? It would seem to me that a radar altimeter-style fuze could work, but one which depends on doppler shift to detonate wouldn't do so before impacting the ground. Ground bursts are not the most effective artillery strategy, and the most effective altitude for an airburst increases proportionally to the size of the shell (the extreme end is found with atomic bombs, which are mentioned here). So is there something I'm not seeing? Otherwise the article should be updated to reflect this. -User:Lommer | ^talk 19:44, 8 December 2005 (UTC)

Proximity fuzes used against targets on land function at a height above the ground. As a fuze approaches the ground the radio wave are reflected off the ground. The frequency changes as the fuze approaches the ground and this is used to determined the Height of Burst (HOB). The HOB can also vary based on the surface type. For example a field would reflect the waves differently then a parking lot. This link has more details.

--HeKeRnd 16:01, 12 December 2005 (UTC)

I understand how a modern radar altimeter works (time delay from pulses), but I don't see how one could employ doppler shift to build an altimeter unless one was using it to calculate velocity and then integrating that backwards to some reference altitude to determine position. The way the article reads now it implies that doppler shift is still being used. -User:Lommer | ^talk 07:01, 13 December 2005 (UTC)

I think the confusion comes from the articles example for doppler shift. Doppler shift comes from the relative motion of something sending out the wave (sound or radio) and the receiver. The passing train example is very common, but in this case it muddles the term. Doppler shift is occurring even before the train passes. The link given by HeKeRnd is very good, and my understanding is that the signal bouncing off the target is a different frequency than the original signal, and mixing these two produces a low-frequency signal which will detonate the shell when the target is close enough to create a strong signal reflection. The shell doesn't need to pass the target. 69.110.48.22 00:05, 2 April 2006 (UTC)

[edit] Misspelling

I'm confused. The word Fuse is clearly misspelled (at least the English version of this word). Why is this article here and why does Proximity Fuse redirect here? Nevermind. I spoke before I had the facts. Fuze seems to be acceptable. I don't understand it but I have to accept it. James084 13:48, 23 December 2005 (UTC)

[edit] Bush?

Bush who? George Bush?70.225.179.182

The Bush mentioned, Vannevar Bush, is unrelated to the Bush political family. Bogsat 13:31, 30 January 2006 (UTC)

[edit] How they found which vacuum tubes would survive the setback of firing from an artillery piece.

I had a conversation with Laurance Halfstad a few years before he passed away in which I asked him how they determined where to start in putting a radio transmitter and receiver into the nose cone of an artillery shell when all they had were vacuum tubes to work with.

Answer: They went to a radio shop in London and purchased an assortment of vacuum tubes which they then took to the top of the Tower of London and dropped them from the top. The tubes which survived gave them a starting point to the design of tubes strong enough to survive the setback of being fired out of an artillery piece.

I received a copy of the book "The Deadly Fuse" and have read it cover to cover.

It is a fascinating account of the developement and fielding of a device to help win WW2. —The preceding unsigned comment was added by Don2158 (talk • contribs) 17:17, 24 January 2007 (UTC).