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Author Topic: Radar Avoidance  (Read 3442 times)

Jake

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Radar Avoidance
« on: November 18, 2006, 11:14:30 PM »
                        A brief ? Essay on Avoiding Police Radar

Ok, first of all, what qualifies me to tell you about radar? Well, having spent most of my adult life
as  a Licensed Merchant Marine Officer, and therefore  trained , and examined frequently in the
various aspects of radar, theory , and application. plus useing several different types as tho' my life
literally depended on proper interpretation, kinda gives me special insight into whats  up with radar.




I guess this establishes my ' bonifides' as someone relatively knowledgable.

So, whats Radar? Simply stated , its a ultra high freq. radio wave  transmitted in a directional band. this band /pattern can be defined as either a vertical narrow band , or a horizontal band.Hold out your hand, palm down, and think of it as a radar signal. Thats what the police units signal looks like if it were visible to the naked eye. The radar beam is kinda hard to define,  but it has a physical size, and caharacteristics similar to a beam of light.the radar is pulsed outward, and the time it takes a pulse to travel to a reflecting object and back is measured and converted to distance . The next pulse shows the object to be a little closer. This rate of closure is speed It requires a few pulses to establish the speed, and a bit more timeto calculate it , um , say maybe a tenth of a second , or so. If the rate of closure is changing,   it will take much longer to lock on a 'reading' on the radar unit. tyhe reading may even be so unstable it cant be used....This is an important thing.

OK, thinking of radar as similar to light, take out your trusty mag lite tonite, and set the beam to a tight spot...and get about 40-50 feet away. Put the flashlight on your forehead between your eyes and look at your T-Bird/Cougie .... In the dark youll notice that some things reflect more than others. thats the optical reflection thats parallel to a radar reflection.... Youll notice something else, as you walk to either side the reflections diminish , as looking kinda slantways to a mirror. MN-12's are pretty slick, so the radar reflection, or' signature' is smaller than some cars...There is another thing youshould take notice of, .... the headlights, they give a pretty strong off center reflection, this is due to they're being parabolic reflectors...... If they were spherical reflectors you would get about 95-99 percent return of reflected light. as it is the parabolics give back almost 75 percent (My guess). In any case , OVER 70 percent of any vehicles TOTAL radar reflection is from the headlights! .... The bigger the signature the longer the range of radar detection... this is important too. If you had some fine woven screening painted black , how much would you see as a reflection? not too darn much!Well, exactly whats that supposed to mean? ... There is some pass thru of light, some but not very much reflected light, Its almost "absorbed"!
Well, the same is true for radar waves. They vary in size depending on the emitter, but they cannot pass thru a fine bronze wire mesh, instead they impinge on the screen , much like magnetic lines of force do when a wire is moved accross them to generate current. As a matter of fact, what happens is the screen mesh completes a little micro circuit, and re radiates a small amount of RF at the radars frequency, but a good percentage of the energy becomes heat, and the re radiated signal is "DIFFUSE", meaning not focused , so its almost negligable coming back to the original radar gun. What's happened is the signal has been absorbed. Will it work with aluminum screening? I dunno, should, but the military uses bronze wire screen in its stealth aircraft..... Go to The Air Force Museum in Dayton, Ohio, and look at the F-117 , in the wings leading edge of epoxy, youll see the screen. I got mine at Mc Nichols Co. about the only place bronze wire screen is available to the general public.
What did I do? I lined the entire front valence with screen, including the vent openings. I split open the headlights , and inserted some in the headlights and resealed them with Goop marine sealant.. I also inserted screen inside the side rear view mirror shrouds, and glued the edges to keep it in place.


In the above photo, you can see the screen, and if you look closely, the screen in the headlights is also visible.

OK, does it work?? well, I wondered about that too, and came up with a plan to test and quantify how well I had succeded. I rented a Stalker Solo radar gun, rated to detect a baseball, and clock it at 440 feet! Wowser!, thats good, but the super stalker clocks baseballs over a quarter mile (about 3 times farther) . I think those two are possibly the best available to law enfoercement, but the Super Stalker is probably outside the price range of most departjments. the rent on the Solo for 3 days was $150 (dont tell my wife, but I hadda know!) We marked a stretch of road with small flags every 1/4 mile , and used marine band hanhelds to test everything. I was clocking other cars 1.25 to 1.5 miles off, even tho the "range rating" on the solo is just 1 mile. My Cincinatti Microwave detector couldnt pick up the Solo till inside the 1 mile range slightly. The Solo couldnt pick up the modified T-bird untill well within the 1/4 mile marker... That means the solo was clocking the fillings in my teeth  in the car, and some other stuff, smaller than about the size of 3 baseballs!!. not too bad but, still detectable, kinda sorta....My guess is the reflection of signs other cars and buildings will confuse all but the best radars  till I can Identify them and slow down. I am almost totally invisible to X-band radar, go figure. and the best is yet to come.....
Cosine error.... never heard of it? a lot of police ossifers havent either. Basically, cosine error is the reduction in speed sensed by the radar gun due to offset of the direction of travel to the line of sight to the target. the cosine of that angle is the factor that is multiplied to get recorded speed from true speed. You allways get a discount , except when the radar is directly ahead of you , or directly behind you... The closer you get before detection , the greater the offset, and your discount on the ticket. You may get slapped with a violation, but allmost allways it will be less than what you were doing..........
'95 T-Bird 5.4L blower and sum stuff
13.6sec 1/4 mi, 300RW at 5250 RPM
GVW 4340 lbs, go figure!


 
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Joe H

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Re: Radar Avoidance
« Reply #1 on: August 02, 2013, 11:50:37 PM »
heh

neat thread 


no offense intended but.................if it can clock baseballs


and QUOTE:
. That means the solo was clocking the fillings in my teeth  in the car, and some other stuff, smaller than about the size of 3 baseballs!!. not too bad but, still detectable


I'm not that lucky.