From: uni@acs.bu.edu (Shaen Bernhardt)
Newsgroups: sci.electronics
Subject: Re: RADAR, RADAR ECM, and RADAR ECCM
Date: 21 Jan 93 05:51:22 GMT
Organization: Boston University, Boston, MA, USA


originally I sent this as a letter, but it occurs to me that I might be
mistaken on some points, or might have some points that others might
like to hear so....:

>To: jcborkow@trident.usacs.rutgers.edu
>Subject: Re: RADAR, RADAR ECM, and RADAR ECCM
>Newsgroups: sci.electronics,rec.autos.driving
>In-Reply-To: <Jan.20.12.40.11.1993.25528@trident.usacs.rutgers.edu>
>Organization: Boston University, Boston, MA, USA
>Cc: 
>Bcc: 
 
In article <Jan.20.12.40.11.1993.25528@trident.usacs.rutgers.edu> you write:
>
>
>     I am currently an electrical engineering student with a vast
>interest in Microwave Engineering and RADAR Systems Engineering.
 
[Stuff Deleted]
 
It's nice to see someone else interested in this material.
I have studied the functionality and process of speed measurement by
radar for some time (Being an avid speeder)
I bought my first radar gun (never had or tried to get a license) when I
was 14.  
 
 
>     However, with all that I have learned and all the books I have
>looked through, I cannot find an answer to this question:
 
>     In NJ, the only police RADAR unit that is legally used by State
>Police is the MPH Industries K-55 X-band RADAR unit. (There are three
 
[Stuff Deleted]
I have had some experience with these units.
 
>     These units also have a jack for an option for an Electronic
>Counter Measure detection/ECCM unit to be attached. I already owned a
 
[Stuff deleted]
 
>I was able to obtain one of these optional ECCM units. However, all
>the unit is is a third antenna, that's battery operated, and it
>displays a third vehicle/object speed. I tried using the unit against
>an X-band spot jammer, and the unit was also fooled by the jammer
>signal. So what is the purpose of this ECCM unit, what is it supposed
>to do, and how is it supposed to do it? What is the purpose of having
>the unit being battery operated? I was not able to get a manual with
>the ECCM unit, so I can't tell you anything more than I observed.
 
I have never played with the ECCM units, but I have talked with troopers
and designers who have.  My impression is that they serve one purpose only,
and that is to identify other sources of emissions... to identify a vehicle
transmitting, and thus facilitate capture.. NOT to defeat a jammer, only
to verify its presence.
 
I would assume that the speed reading is a passive reader designed to 
pickup the signal of a jammer and display the speed it is transmitting.
 
Theoretically the use of said unit would be as such:
 
1>  Trooper with instant on/constant speed measureing unit observes a 
car traveling at what he/she feels to be a unusually high speed.
(Note that trooper has the ECCM unit)
 
2>  Trooper iluminates the target vehicle, but gets only a 57 mph reading
(Despite the fact that the offending vehicle seems to be traveling at 90+)
 
3>  Trooper deactivates the radar transmitter (freezing the reading 57mph)
 
4>  The ECCM unit (not powered by the trigger on the k-55 unit) continues
to recieve and display 57 in the absence of any trooper transmission
 
5>  As Trooper is not transmitting, yet a signal is still present:  Another
transmission must be present, and transmitting at 57mph.
 
This is consistant with the typical jammer methods I have observed.
1>  Jammers are of two types:  Active or Passive/Active.
 
The active types just transmit 57 mph (Or whatever they are set to) all the
time.  (Setting off all the radar detectors within range I might add)
 
The Passive Actives wait until they recieve a signal (via external speaker
jack in an escort/pasport detector for example) and THEN transmitt 57mph
 
Either way....
 
1>  With the ACTIVE jammer, the trooper will receive a signal without
transmitting.  (Assumeably this will result in a display on the ECCM unit)
 
2>  With the Passive/Active jammer, the trooper will receive a signal 
without transmitting (Having triggered the transmitter)  I believe
all the transmitters have a good deal of lag after the trooper lets
up on the trigger.  (Jamming transmitters that is)
 
>
>     Some observations I have to answer any unanswered questions:
>
>   One of the easiest ways to defeat ECM units is to continuously
>change frequency. However, police RADAR X-band RADAR must be
>10.525 GHz, so such a tactic cannot be used.  
 
Ah, but the stalker does exactaly this, or will soon (Wideband Ka)
 
>   Another way to defeat ECM is to increase power output. The jammer
>had a cavity output of 200mW, which is 10-15 times the output of
>the RADAR unit. The RADAR unit would have to have a power output in
>the range of a few watts to be able to defeat the jammer.
 
This is decidely unpopular... the key in design lately has been LOW
power.  To much cancer scares right now.  ECM is so rare as to make this
pointless.
 
>   The ECCM unit, I think, would be somewhat useful (maybe 40% of
>the time) against mechanical means of RADAR jamming (vibrating
>metal or stealth materials) if the two antennas where placed far
>enough apart. However, mechanical RADAR jamming is extremely
>unreliable, and there is no sense in making a unit to defeat it.
 
I really dont think the ECCM unit does anything other than listen....
I dont know what else might be going on......
 
>   The jammer worked on the principle of sending out a pulsed wave
>so the RADAR unit would receive a higher, false echoed signal to
>drown out the actual vehicle signal. There is a RADAR unit, the
>Kustom H.A.W.K. system, which defeats such an ECM signal by using
>a PCM signal. Unrecognizable signals (i.e. a pure sine wave) are
>ignored. However, the K-55 RADAR unit I have uses a pure sine
>wave output, and, hence, no sinal identification trickery.
 
True, some models of the hawk also have a feature that permits passive
signal reception in the hold mode to detect (assumably) transmitters
(Jammers)  Note that the EFI features of most guns are EXACTALLY this,
just listening for similar signals that might interfere with the gun...
Many troopers know enough to suspect something when a car goes by
and lights up the EFI indicator.
 
>     Lastly, no police RADAR units that I have seen have this
>ECCM unit hooked up. It might be that maybe it doesn't actually
>work. Any insight or comments greatly appreciated.
 
I think the real point is that there are so few jammers that its not
considered cost effective.
 
 
>                                                   Jason
>                                   (jcborkow@trident.usacs.rutgers.edu)
 
 
uni
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