Sponsor Message:
Civil Aviation Forum
My Starred Topics | Profile | New Topic | Forum Index | Help | Search 
How Do Birds Appear On Radar  
User currently offlineSAAB340 From United States of America, joined Sep 2001, 320 posts, RR: 2
Posted (14 years 7 months 2 weeks 6 days 2 hours ago) and read 2881 times:

Hey all!!

I just wanted to know how big on an object it takes to appear on a radar screen??

I have heard many times on approach of sudden dots being picked up on radar!

Anyone have some more info on this issue??


1 replies: All unread, jump to last
User currently offlineAerokid From Belgium, joined Jun 2000, 348 posts, RR: 0
Reply 1, posted (14 years 7 months 2 weeks 6 days 2 hours ago) and read 2864 times:

Appearence on a radar of an object depends mostly on the radar cross section (RCS) of that object and off course also on the sensitivity of the radar. RCS of aircraft can vary a lot: a 747 has a RCS of a few dozen square meters, whilst an F-117 has a RCS smaller than that of a compact disc. For birds: I don't think a single bird will appear on a radar screen but a swarm of birds might. Just like you can't see a single raindrop on the screen whilst clouds are visible.

Actually, you really don't wanna see birds and clouds on a radar screen (at least not an ATC radar, the on-board weather radar is another case off course), so various techniques are used to filter these echo's out. They can monitor the speed of the objects and everything that moves slower than an aircraft would normally do will be taken off the screen. Clouds can be eliminated by using circular polarisation of the radar waves, reflection against rainddrops turns the direction of polarization and these echo's are not detected by the radar antenna.

I've been visiting a radar station a few years ago (it was a high school excursion) and they turned the filters off to show us how sensitive the radar is: you could see power lines on the screen: cables of only a few inches thick.

Hope this answers your question.

Best regards,

Top Of Page
Forum Index

This topic is archived and can not be replied to any more.

Printer friendly format

Similar topics:More similar topics...
How Do I Book A Ticket On Air China? posted Sun May 21 2006 09:43:15 by FlyingNanook
A380 (how Do You Get On And Off) posted Mon Oct 11 2004 13:39:55 by TheGregster
How Do They Decide On Registration Numbers posted Fri Apr 13 2001 23:14:56 by Fly_yhm
How Do They Fill Up Widebodies On Domestic Routes? posted Tue Aug 1 2006 04:57:12 by BizJet
How Do I Determine 737-200/500/700 On WN? posted Thu Oct 13 2005 04:32:47 by LUVRSW
How Do You Upsell An Airticket On EK? posted Sun Jul 24 2005 15:24:20 by JeffrySkY
How Do I Get Premium Seats On CO? posted Sat Feb 5 2005 23:43:35 by AA737-823
How Do I Fly On SQ-A380 First Flight posted Fri Jan 21 2005 05:00:57 by Boeingforever
How Do Transatlantic Relief Pilots Sleep On A 757? posted Mon Dec 6 2004 05:28:23 by ACAfan
How Do I Find The Exact Plane I Flew On? posted Fri Aug 20 2004 04:06:28 by IslipWN