Few questions about a RD. Anatomy 101

[YZFR1]

Here are a few oddball questions I have about RD's.


#1: Why is there a dark piece of plastic in front of the antenna, could it be clear, or another color(Is it polarized?)

#2: Could someone add to the antenna to increase sensitivity?

#3: My classmate told me that I could polish the brass cone shaped antenna in my PNI to raise sensitivity - is this true?

[kpatz]

#1: Why is there a dark piece of plastic in front of the antenna, could it be clear, or another color(Is it polarized?)

The plastic protects the radar antenna, and allows infrared to pass through to the laser sensor. It could be made clear, but it wouldn't be as asthetically appealing.

#2: Could someone add to the antenna to increase sensitivity?

I suppose you could add on an external horn to increase range, but it would also make the RD more directional - you'd lose sensitivity to off-axis radar.

#3: My classmate told me that I could polish the brass cone shaped antenna in my PNI to raise sensitivity - is this true?

I doubt it would make any difference.

[jimbonzzz]

#1: Why is there a dark piece of plastic in front of the antenna, could it be clear, or another color(Is it polarized?)

In the past, some units contained a fresnel lens for the laser detection portion. To my knowledge these do no polarizing effect on the radar.

#2: Could someone add to the antenna to increase sensitivity?

Sure. You could get a LOT of gain. But this would come with its own problems such as also amplifying the noise, more directional, etc. However, some people overseas have made addon horns to increase sensitivity to photo radar, check out http://www.flitsservice.nl for examples.

#3: My classmate told me that I could polish the brass cone shaped antenna in my PNI to raise sensitivity - is this true?

If they did a crappy job manufacturing it you might get a little bit. But not enough to make it worth the trouble.

Jim

[YZFR1]

Awesome! Thanks for the reply. Is the lense extreemly dark for any reason?

[joop1987]

#1: Why is there a dark piece of plastic in front of the antenna, could it be clear, or another color(Is it polarized?)

The plastic front is actually a light filter. It lets IR light through and filters out other light frequencies.

Here's a picture of a remote controls light going through the filter.

[greateratlanta]

In the past, some units contained a fresnel lens for the laser detection portion. To my knowledge these do no polarizing effect on the radar.

Interesting idea, in theory it would seem like this would be very effective in alerting the detector to low power, indirect laser waves. I wonder why it has not caught on with the big 3 manufacturers . . . maybe it causes too many falses??? On a side note (not sure if this has any relevance) headlights on older vehicles work by a light source being reflected on either a concave mirror or a bunch of plane mirrors at 90 degree angles and then focused by a Fresnel lens. These headlights are designed to focus projected light waves with 400-700nm wavelengths, whereas the Fresnel in front of a laser sensor would be used to focus incoming laser waves with1550 nm wavelengths(???) at the sensor/antenna. Can a standard Fresnel designed to focus visible light waves handle laser waves that have a much longer wavelength? I guess since there is no filtering with a clear glass/plastic lens that it would be capable . . . I stink at physics, so someone with more knowledge on this please chime in and tell me how it works.
Thanks!

-Clayton

[nvr2fast]

#1: Why is there a dark piece of plastic in front of the antenna, could it be clear, or another color(Is it polarized?)

In the past, some units contained a fresnel lens for the laser detection portion. To my knowledge these do no polarizing effect on the radar.

#2: Could someone add to the antenna to increase sensitivity?

Sure. You could get a LOT of gain. But this would come with its own problems such as also amplifying the noise, more directional, etc. However, some people overseas have made addon horns to increase sensitivity to photo radar, check out http://www.flitsservice.nl for examples.

#3: My classmate told me that I could polish the brass cone shaped antenna in my PNI to raise sensitivity - is this true?

If they did a crappy job manufacturing it you might get a little bit. But not enough to make it worth the trouble.

Jim

I've been to http://www.flitsservice.nl and for the life of me I can't read or find the right sections... sigh.

[jimbonzzz]

I've been to http://www.flitsservice.nl and for the life of me I can't read or find the right sections... sigh.

Click on "Detector Shop" at the top of the page...

[SpeedFreak]

Since this topic is already opened, i always wanted to know if scratches on the lens are reducing sensivity?? I dont think so but any of you guys got an opinion on this?

[stalker]

I doubt it...I could be wrong tho....