h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Copy/pasting the references used here would be a very useful idea so that I can include the correct up-to-date links in my article.

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right

Here you are:

<------snip------>





Technology:
Basic Principle
| Main Components
| Signal Processing
| Antennas
| Side Lobe Suppression
| Phased Array Antennas
| Antenna Beam Shapes
| Monopulse Antennas
| Continuous Wave Radar
History:
Overview
| Isle of Wight Radar During WWII
Theoretical Basics:
The Radar Equation
| Ambiguous Measurements
| Signals and Range Resolution
| Ambiguity and PRFs
Civilian Applications:
Police Radar
| Automotive Radar
| Primary and Secondary Radar
| Airborne Collision Avoidance
| Synthetic Aperture Radar
Military Applications:
Overview
| Over The Horizon
| Low Probability of Intercept
| How a Bat's Sensor Works
Electronic Combat:
Overview
| Electronic Combat in Wildlife
| Range Gate Pull-Off
| Inverse Gain Jamming
| Advanced ECM
| How Stealth Works
| Stealth Aircraft


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Copy this to the bottom of the entry and replace the ... with ... in the line that pertains to the entry itself.

Hi Sir Bossel

I've just read your entry on Monopulse antennas. I presume the antennas you decribe are for a specific military application. They are certainly not like any ATC Monopulse antenna I have ever seen. If so you might want to make that clear. The ATC Monopulse antennas consist of a rotating multielement array with seperate left and right half to provide the Sum and Diff signals.

||||||||||||||||||||
LLLLLLLLLCRRRRRRRRR
||||||||||||||||||||

Where the Ls are connected together and the Rs are connected together. The C provides the Control pulse P2 (or P5 or mode S)


SK

I'm sure that illustration worked when I previewed it. Maybe it depends on screen size. I was on a different computer when I did it. If it doesn't work for you, I'm sure you get the idea. I probably shouldn't have posted it here, as I'm don't think you are ( or anyone is) reading this thread now. Anyway if you do there it is.

SK

Oh that's only a question of fonts. There's a fixed width font within the 'post to conversation' window but there's non-fixed-width font on site, so an 'i' and an 'm' for example don't occupy the same space.

As to the question... The Left/Right Array monopulse system is not a question of military or civil application. The only difference is that your sketch shows an active antenna ie: there's no offset radiator/receiver pickup. Therefore the Left/Right thing uses the full aperture for the Sum channel and one half of it for each of the difference channels. Thus the Diff beams are wider and will pick up noise from areas that were not illuminated by the Sum beam, but that's still good enough for ATC applications where transponders are used.

The contraption shown in the entry uses the full aperture for all three (sum+deltaL+deltaR) beams, with only slight misalignment losses, and therefore is better suited for working with purely 'passive' targets. This is true for military applications, but not as a rule.

I check in from time to time.

Ladies and Gentlemen...




I now declare this project...





... finished!



I'd like to apologise for the slight technical delay (erm...) but I hope you won't take it too seriously. After all, I've got to earn some money through w*rk.





Bossel

*Wakes up*
Sorry - I was sleeping there. Did I hear someone say that the project is actually finished?
I must have been dreaming!
When will it appear on the front, do we know?

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Good Morning, Sörr!

No, you're not dreaming! Actually I found a round tuit over Xmas and gave it the last touch (although I'm afraid that some of the external links don't work anymore). As to the time of appearance... dunno. I gathered from a posting from Anna somewhere else that it might be split into batches and its appearance might be distributed as one section per week but I don't know what's going to happen. First of all, there's the question of subbing the piece and getting rid of all the Denglish in there

Great, glad to hear it.

yes, finally

I don't believe it!

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