Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: Notesfiles $Revision: 1.7.0.10 $; site uiucdcsb
Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxn!ihnp4!inuxc!pur-ee!uiucdcs!uiucdcsb!jabusch
From: jabusch@uiucdcsb.CS.UIUC.EDU
Newsgroups: net.aviation
Subject: Re: IFR procedure questions
Message-ID: <5900004@uiucdcsb>
Date: Tue, 4-Mar-86 11:52:00 EST
Article-I.D.: uiucdcsb.5900004
Posted: Tue Mar  4 11:52:00 1986
Date-Received: Fri, 7-Mar-86 04:13:47 EST
References: <339@bunny.UUCP>
Lines: 13
Nf-ID: #R:bunny.UUCP:339:uiucdcsb:5900004:000:598
Nf-From: uiucdcsb.CS.UIUC.EDU!jabusch    Mar  4 10:52:00 1986



	There is no good reasoning for cycling the transponder in
any mode outside of standby.  As was pointed out in an earlier
response, the ATC is hardly going to have time to watch for quick
changes of individual digits, especially in a busy location.  That's
the reason the 'ident' is found on transponders.  It sends along 
one extra pulse during replies in all of the civilian reply modes 
that can be used for easy location on the ATC's screen.  The ident
functions as a timer, usually maintaining its state for 20 to 25 
seconds, plenty of time to locate it visually on the radar.

John Jabusch