Path: utzoo!attcan!uunet!ginosko!gem.mps.ohio-state.edu!tut.cis.ohio-state.edu!attctc!sampson
From: sampson@attctc.Dallas.TX.US (Steve Sampson)
Newsgroups: sci.electronics
Subject: Re: "Spybuster" AD COPY
Summary: Self Suppression
Message-ID: <9092@attctc.Dallas.TX.US>
Date: 24 Aug 89 05:45:33 GMT
References: <17100002@inmet> <647@anasaz.UUCP> <791@mipos3.intel.com>
Organization: The Unix(R) Connection, Dallas, Texas
Lines: 16

In article <791@mipos3.intel.com>, jmasters@pcocd2.intel.com (Justin Masters ) writes:
> In article <647@anasaz.UUCP> john@anasaz.UUCP (John Moore) writes:
> +
> +The ironic thing is that I would probably use one IN an airplane
> +as a collision alert detector.
> 
> Wouldn't you just get the reflections from a plane at 0 feet?  Seems to me it
> would cancel out other planes' signals and get yours.
> 

Well the common method used here is a suppression circuit triggered by your
transponder.  Various ideas come to mind if no suppression pulse is available
on your transponder.  Maybe something to switch the antenna to ground during
replies based on detected power at the transponder antenna...  A little more
circuitry and maybe you could decode the Mode C replies?  Anyone know the
Mode C altitude report format - say a file of altitude vs code sent?