Radar warning

**androider** · 11-27-2008, 11:22 AM

I do 81wpm, but yeah, you got me, I'm younger than you.

You say that radar detectors are usually too late to detect the signal, and if I get the warning, that means the cop can already clock me. That's not true. Their signal flies for hundreds of yards beyong their view and they can only detect my speed when they can actually see me. So it works very well.

**mwenn1** · 11-27-2008, 12:38 PM

The guys at trapster say they are working on an android version of their program but had no release date as of yet. I have used it before with win mobile and it is a nice program. I also no that the new escort radar dectector has gps in it and has a database of photorader spots which you can add to and keep up to date by downloading it from the internet. This info would be nice to have as I live in the Phoenix area and they just added a bunch of new cameras on the highways, as well as the red light cameras. I don't run red lights but do like to speed on occasion so it would be nice to know when you are coming up on a photo camera.

**CJ Chitwood** · 11-27-2008, 05:01 PM

Originally Posted by androider

I do 81wpm, but yeah, you got me, I'm younger than you.

You say that radar detectors are usually too late to detect the signal, and if I get the warning, that means the cop can already clock me. That's not true. Their signal flies for hundreds of yards beyong their view and they can only detect my speed when they can actually see me. So it works very well.

Except they're still just radio waves. They don't magically arc around corners. They have to bounce off stuff. It's called "line of sight" by people who work in the radiotelecommunications industry. Now, with AM, and lower frequencies (50MHz is typically considered the highest), you can get a lot of atmospheric propagation and even talk all the way around the world on a single CB transmitter with no repeater, but RADAR uses frequencies in the gigahertz range. I forget the actual numbers, but it's close to today's cellphones and WiFi. These just don't follow the curve of the earth like old AM CBs do. They've got to bounce off of something, or else it's got to be line of sight.

Now, if you're in a hilly place like north Georgia, and there are metal signs and parked cars/tractors/whatever to bounce the signal, then yeah, but where I live it's flat, and there's not much in the way of obstructions on most roads, so -- again, where I live -- if your detector goes off, you better hope he was pointing it at the car ahead of you and hope you're going considerably slower. Also, here, they'll just set up a tripod with a radar gun on it and have two or three cops in the median, not even trying to hide. And yet they still pull people over. I guess Floridians are just stupid.

Besides, the only time you'll detect radar is when the radar gun is active. Out here, they wait until they can see you and then pull the trigger. Then they get your speed on their readout at about the same time you realize you've been tagged. So, again, a detector is pointless -- at least for me, at least here.

**androider** · 11-27-2008, 11:06 PM

It sounds to me like you've never used a radar detector. I hear the detector signaling me of a cop up to a mile before I see him.

Now let ME school you about waves. A fence, a cement wall, or a wall of trees is enough to make the probe signal that the cop's radar is emitting propagate through the road. This signal reaches me, however it does not reach back to the cop in order to tell him what speed I'm going. He can only clock my speed when his waves can reach my car and travel back to him. This means that he has to physically see me. However, my radar detector doesn't need to physically see the cop's radar in order to pick up his bouncing waves.

Please don't try to be a little technical pest correcting that^. Even if it does have a mistake, I am speaking from the experience of owning a radar here in NY. So I am explaining it to you the way I think it works for me. Most cops here keep their radars on and I get the signal way before they see me.

**Arr MiHardies** · 11-29-2008, 04:34 AM

Originally Posted by CJ Chitwood

These just don't follow the curve of the earth like old AM CBs do. They've got to bounce off of something, or else it's got to be line of sight.

To be technically correct, AM radio waves do not follow the curve of the earth. they are line of site, just like every other radio wave. However, the wavelength of AM radios waves are of just the right frequency that they bounce off the stratosphere, back down to the earth, giving it a much wider terrestrial range than most other forms of radio communication.

Originally Posted by androider

A fence, a cement wall, or a wall of trees is enough to make the probe signal that the cop's radar is emitting propagate through the road. This signal reaches me, however it does not reach back to the cop in order to tell him what speed I'm going. He can only clock my speed when his waves can reach my car and travel back to him. This means that he has to physically see me. However, my radar detector doesn't need to physically see the cop's radar in order to pick up his bouncing waves.

Not entirely accurate either. if the radio wave can pass through a wall, it can most certainly pass back so long as the signal is strong enough. However, for a cop, this would present several issues. First the cop would have to know someone is on the other side of the wall to be tagged. then he would have to blindly fire his radar gun and hopes he marks them. third, any signal coming back through the wall would be useless because any materials between the cap and the target would alter the radio waves as they passed through them, resulting in an inaccurate result, if any. And third, assuming none of the above were actual issues, and the cop did manage to know of a target, tag it with his gun and obtain an accurate readout, the cop would still have to go around said wall to reach his target

You also have to consider that in some states, they not only use radar, but lasers for the purposes of checking speed. Lasers have a much tighter band that doesn't tend to scatter as much and remain usable or detectable. In states that use laser, chances are, if your detector is going off, they've already tagged you.

**Arr MiHardies** · 11-29-2008, 04:34 AM

okay, so I'm a technical pest

**androider** · 11-29-2008, 10:45 AM

You sound like you might know what you are talking about, however I don't see how your reply to what I said is any relevant.

You speak of a wall, and discuss how the signal travels through the wall, etc. I never said anything about the cop detecting me when I'm behind a wall.

I am not a "technical pest" in radio technology, but I can infer a few things from seeing my radar detector work in real life. If I'm driving down a road and suddenly hear the Ka band alarm on my detector, then I slow down. As soon as I finish going up hill, I see there is a cop about 75 yards away. I definitely didn't have sight of the cop and hid radar, but I did get the signal. This means that the waves must have bounced off SOMETHING to reach me, because the line from the cop's radar to mine wasn't straight.

So don't make conclusions about me not being "entirely accurate" yet.