Text 15925, 122 rader
Skriven 2005-11-12 10:41:21 av Raymond Yates (1:3613/48)
  Kommentar till text 15914 av Michiel van der Vlist (2:280/5555)
Ärende: looters in NO
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 >>>> It will detect it if the radar signal bounces off of any object
 >>>> in the front of the building. You know, the multipath signal of
 >>>> VHF and up.

 MvdV>>> But the reflected signal will be 20 to 40 dB weaker than the
 MvdV>>> direct signal. That means you have to get a lot closer to
 MvdV>>> detect it.

 >> That'd depend on the sensitivity of the detectors front end.

 MV> No, it doesn't. The difference in signal level depends on a lot of
 MV> things, but the sensitivity of the receiver is NOT one of them.

I almost hate to get into the middle of this, but I will, anyways. <g>

North Carolina is one of those states that allows the use of radar detectors.

I've used them for years. At one point I had two differet models in my car
for comparison purposes. I found I could pick up the side and rear lobes very
well, at different ranges with either unit, well before entering the detection
zone. The difference was in the front end recievers, which is what Roy was
trying to explain. In the case of encountering the front lobe, one unit was
signifcantly better than the other, having nearly twice the range. Against
pulsed radar (where the officer triggers it at random moments rather than the
unit being on all the time called the "Speed Gun"}, the better of the two
units showed a markedly better range if it was triggered against a car in
front of me than the other unit.

True, the signal level reamins constant, but the ability of the reciever to
detect that signal is critical. That /is/ a function of the electronics,
obviously.

After I was done with the comparison, I placed the weaker of the two recievers
facing towards the rear of the vehicle. I figured that if the police can mount
two transmitters one facing forward and one facing rearward, the least I can
do is set recievers to match. <g>

Oh. I could pick up radar transmitters on stores, up to a half-mile away..
from nearly any orientation to the store, thanks to multi-path. after a while
I got to know where the stores were, and any variance in the signal might mean
there was a police-car nearby.

 >>>> Depending on the sensitivity of the detector, it would pick up
 >>>> a signal from backscatter.

 MvdV>>> The signal must be detectable. After all that is how the thing
 MvdV>>> works. But the signal is a lot weaker than the direct signal,
 MvdV>>> so you have to be real close. Most likely too close to be of
 MvdV>>> any use.

It depends. if the unit indicates a signal at all from a distance, it's a
clue.. Most of the units here have a scale, from weak to strong. The key is to
adjust speed when the first signal arrives.

This presumes, of course, that one is speeding.

In my area, I have a four-lane highway I travel six times a week at minimum.
It's the only road to town, there is no choice. The posted speed limit is
55mph (88kph_). Nearly everyone without exception travels faster than that,
usually 65mph (104 kph) to 70mph (112 kph) at all times, day or night. Now
were I to travel at teh posted speed limit I would be impeding traffic in the
practical sense. So the smart thing to do is maintain the speed of traffic
which is still 10 over the limit, but is much safer. In this case the radar
detector is a wise thing as it prevents the ticket if there is warning enough
in time. the stretch of highway I travel (about 15 miles/24km) is frequently
patrolled by both the local police and the State Patrol.  While they usually
do not write tickets un traffic is flowing smoothly up to about 7mph (11kph)
over, there are individual officers that are more stringent.

Where they really clamp down is on the flagrant speeder which I would think
fits your "Road Pirate" miniker, that travels in excess of 100mph (160kph) on
a posted road of 55 (88). In this I agree, while I disagree with writing
tickets if traffic is flowing smoothly though abve the limit..

 >> As long as I'm not yet in the camera's range, I'll be just fine.


 MvdV>>> with it most of the time. Now the roads are so crowded that
 MvdV>>> excessive speeding is irresponsible if not impossible. Can't
 MvdV>>> speed in a traffic jam...

 >> Wanna bet? I've seen youngsters jump from lane to lane, cutting
 >> people off and causing accidents behind them in traffic jams.

 MV> Not possible in the traffic jams they have here. In such a jams cars
 MV> are bumper to bumper at walking speed or are at a complete stop. One
 MV> can not "jump form lne to lane", there is simply no room to go
 MV> anywhere but go with the flow.

Roy's describing the other type of traffic jam, the one at speed.

On Interstste 40, which runs from Wilmington to Raleigh (actually it runs to
California, but that's not important) the posted speed limit is 70mph (112kph)
for the majority of the route, but decreases to 55mph (88kph) when one gets
closer to Raleigh.  Most drivers tend to ignore that and continue driving 60,
or, perhaps 65. Rlaeigh is a large city in a heavily suburban area, and many
people will commute as mucgh as 50 miles (80k) to work one-way, every day.
I have been in traffic at speed in the morning rush hour where everyone is
traveling 70mph (112kph) excpt for a few idiots that jump from lane to lane in
the attempt to go faster than the average. Tha's what roy is describing, the
"at speed" traffic jam. I don't know if you have ever experienced this or not,
but ti's different from the stopped traffic jam which we call "gridlock",
whether it's in a city or not(the precise term gridlock referes to traffic in
cities where the cross streets are also full of stopped traffic, but the term
is used to generically describe any traffic that is immobile).


 MvdV>>> Plus that the methods of detection have improved to the point
 MvdV>>> that there is no escape. The latest system is "traject
 MvdV>>> controle". Camaras at checkpoint A record you time of passing
 MvdV>>> and then when you pass checkpoint B five kilometres further
 MvdV>>> down the road you are clocked again. Arrive their too early
 MvdV>>> and you get the ticket in the mail.

The New York State Thruway was doing that in the 1950's, where they ticket you
had picled up at the entering tollbooth had your starting time stamped on it.
When you turned it in topay your toll, the tolltaker would check the time (the
computer did that) and tell you what your toll was while the machine was
printing out your speeding ticket.

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 * Origin: Ray's Rocket Shop - Out to Launch (1:3613/48)