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  1. #1
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    Default info on radar and radar bands! also L,S,C,V BANDS!!

    Police Radar Units use an unmodulated continuous wave and measure reflections or echoes of the original signal, there will be a difference in the returning signal from the original signal, the speedtrap measuring device will calculate this difference and present it in the format of a speed reading. Radar Speedtraps work on the Doppler Shift priciples. This relies on the fact that an object moving relative to a wave source will alter that wavelength by either increasing the wavelength (lower pitch) if it is receding from the source or decreasing it (higher pitch) if it is moving towards the source. If you have ever had an aircraft fly close overhead or a car travel past at high speed you may have noticed that as the vehicle approaches, the pitch of the noise is higher and gets lower as it moves away, this is doppler effect.

    Police Laser units or Lidar ( Light detection and ranging ) use an infra red wavelength. They send out a beam of light which will travel at about 30cm ( 1ft ) per nanosecond then will reflect off a vehicle back to the speed gun. The time ( in nanoseconds ) it takes for this to happen ( divided by 2 ) gives the gun the distance from the vehicle, this can be done hundreds of times in half a second so the difference between the distance readings over a very short period of time can be used to calculate the speed of the vehicle, and they are very accurate.

    S Band
    First used in 1947 on 2.455 GHz these consisted of multiple pieces of equipment including a separate transmitter and receiver, a pen recorder and a needle type speedometer, so a very cumbersome and unwieldy unit to operate. Detection range was only 150 to 500 feet. Now obsolete.

    X Band
    Developed during the 1950s and in use since about 1965. X Band ranges between 10.5 and 10.55 GHz (10.525 with a tolerance of 0.025), compared to other bands it has low frequency and high output. This makes it particularly easy to detect, in fact it is possible to detect at up to 4 miles away although it's own useful range is obviously a lot less than this. Unfortunately because intrusion alarms, radio masts, and door openers use a similar signal these can be the cause of a lot of false alarms.

    K Band
    This came into use in 1976-8 firstly for mobile units and uses 24.150 plus or minus 100 MHz (to give 24.050 to 24.250 GHz), or 24.125 plus or minus 100MHz (to give 24.025 to 24.225 GHz). Because water will absorb wavelengths around 22.24 GHz it can be absorbed more easily by water in the atmosphere so a rainy day may give a weaker signal. K Band can be detected anything upto 2 miles away on a good clear day. Traffic light sensors and some automatic door openers use K Band transmitters so a false alarm may result when approaching these devices.

    Ka Band / Ka WideBand
    Came into force in 1983-7 and uses 34.2-35.2 GHz, Ka Wide Band detection range is upto 1/2 mile.

    Ka Super Wide Band
    1992 Developed from Ka Wideband, Superwide Band can use any frequency between 33.4-36.0 GHz.

    Ku Band
    13.45 GHz Has been tested in the UK and is used on the continent.

    Laser 904 nM
    A mobile unit the laser gun can pinpoint a target in a lane of traffic, it takes less than half a second to get a reading wheras a radar can take 2-3 seconds. It can't be used from behind glass, requires a very steady hand, and at 1000 feet the beam is 3 feet wide, at 1 and 1/2 miles the beam is 2 lanes wide

  2. #2
    Lead Foot
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    very informative, I wish I would still be in school that would make a good report, again thanks for this descriptive info, I tought Ka band was developed much later like 1995+ :?

  3. #3
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    Quote Originally Posted by LiQuiDz
    very informative, I wish I would still be in school that would make a good report, again thanks for this descriptive info, I tought Ka band was developed much later like 1995+ :?
    i just found that info from the net.... i can check on the ka band to see when it first come out!

  4. #4
    Old Timer
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    When did laser start coming into use?
    If I'm passing you on the right, YOU are in the wrong lane!

    If speed kills, how come I'm still alive?

    Active Countermeasures: V1 3.858, Escort Redline, Beltronics STi-R+, LI Dual 7.1x CPU/8.7 Heads (front)
    Other/Backup Countermeasures: V1 3.813 (loaned to friend), Beltronics Pro RX65 M4 6.3
    Vehicle: 2002 Audi A4 1.8T Quattro
    LEO Toys: Kustom Pro Laser II & III
    Encounters/Saves August 2011: Radar 3/1, Laser 0/0


  5. #5
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    i've also found out that theres L S v AND C BANDS!

    L band (20-cm radar long-band) is a portion of the microwave band of the electromagnetic spectrum ranging roughly from 0.39 to 1.55 GHz. It is used by some communications satellites, and by terrestrial Eureka 147 digital audio broadcasting (DAB). In the United States, the L band is held by the military for telemetry, thereby forcing digital radio to in-band on-channel (IBOC) solutions. DAB is typically done in the 1452–1492-MHz range as in Canada, but other countries also use VHF and UHF bands.

    The Global Positioning System carriers are in the L band, centered at 1176.45 MHz (L5), 1227.60 MHz (L2), 1381.05 MHz (L3), and 1575.42 MHz (L1) frequencies.

    WorldSpace satellite radio broadcasts in the 1467–1492 MHz L sub-band.

    Mobile phones operate at frequencies between 800 and 1900 MHz.

    The different NATO L band is defined as frequency band between 40–60 GHz (5–7.5 mm).
    -------------------------
    The S band ranges from 2.0–4.0 GHz., crossing the imaginary boundary between VHF and SHF at 3.0GHz. It is part of the microwave band of the electromagnetic spectrum. The S band is used by weather radar and some communications satellites. The 10-cm radar short-band ranges roughly from 1.55 to 5.2 GHz.

    In the U.S., the FCC approved Digital Audio Radio Satellite (DARS) broadcasts in the S band around 2.3 GHz, currently used by Sirius Satellite Radio and XM Satellite Radio.
    --------------------
    C band ("compromise" band) is a portion of electromagnetic spectrum in the microwave range of frequencies ranging from 4 to 6 GHz.

    C band is primarily used for satellite communications, normally downlink 3.7–4.2 GHz, uplink 5.9–6.4 GHz, usually 24 36-MHz transponders on board a satellite. Most C band satellites use linear polarization, while a handful (particularly older Intelsat satellites) use circular polarization.

    The applications include full-time satellite TV networks or raw satellite feeds, although subscription programming also exists. There are more than 20 C-band satellites in Geosynchronous orbit serving North America, which provide more than 250 video channels and 75 audio services. Typical antenna sizes on C-band capable systems range from 7.5 to 12 feet (2 to 3.5 m).

    This contrasts with direct broadcast satellite, which is a completely closed system used to deliver subscription programming to small satellite dishes connected to proprietary receiving equipment.

    C band is highly associated with TVRO satellite reception systems or "big dish" systems. Larger antennas and more expensive receivers, C band usually provides better video quality and is less affected by rain attenuation than the Ku band.

    The NATO C band is defined as frequency band between 0.5 and 1 GHz (0.3 and 0.6 m).
    ------------------------------
    The V band (vee-band) of the electromagnetic spectrum ranges from 50 to 75 GHz. The V band is not heaviliy used, except for millimeter wave radar research and other kinds of scientific research. Not to be confused with the 600–1000MHz range of Band-V (band-five) of the VHF frequency range.
    -------------------------------
    The Ku band ("kay-yoo" kurz-under band) is a portion of the electromagnetic spectrum in the microwave range of frequencies ranging from 12 to 18 GHz.

    Ku band is primarily used for satellite communications, particularly for satellite backhauls from remote locations back to a television network's studio for editing and broadcasting.

    Ku band is split into two segments by the ITU.

    The 11.7 to 12.2 GHz band is known as FSS (fixed satellite service, uplink 14.0 to 14.5 GHz). There are more than 22 FSS Ku-band satellites orbiting over North America, each carrying 12 to 24 transponders, 20 to 120 watts per transponder, and requiring a 0.8-m to 1.5-m antenna for clear reception.

    The 12.2 to 12.7 GHz segment is known as BSS (broadcasting satellite service). BSS/DBS direct broadcast satellites normally carry 16 to 32 transponders of 27 MHz bandwidth running at 100 to 240 watts of power, allowing the use of receiver antennas as small as 18 inches (450 mm).

    Ku-band signals can be affected by rain attenuation.

    NBC was the first television network to uplink a majority of its affiliate feeds via Ku band in 1983
    -------------------------------
    The Ka band (kurz-above band) is a portion of the K band of the microwave band of the electromagnetic spectrum. Ka band roughly ranges from 18 to 40 GHz. The 20/30 GHz band is used in communications satellites, downlink 18.3–18.8 GHz and 19.7–20.2 GHz. The term Ka band is frequently used to refer to the recommended operating frequencies of WR-28 rectangular waveguide, which is 26.5 to 40.0 GHz.

    --------------------------------
    K band is a portion of the electromagnetic spectrum in the microwave range of frequencies ranging between 12 to 93 GHz. K band between 18 and 26.5 GHz is absorbed easily by water vapor (H2O resonance peak at 22.24 GHz, 1.35 cm). The letter K comes from the German language word kurz, meaning "brief" or "short".

    The NATO K-band is defined as frequency band between 20–40 GHz (7.5-15 mm).

    Ka band: K-above band, 18–40 GHz for radar and general communications
    Ku band: K-under band, 12–18 GHz for satellite communications
    -------------------------------
    The X band ranges from 8.0–12.0 GHz. It is part of the microwave band of the electromagnetic spectrum. The X band is used by some communications satellites and by X-band radar. The 3-cm radar spot-band roughly ranges from 5.2–10.9 GHz.

    -----------------------------------

  6. #6
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    i cant find any info on laser or lidar as its also known, its harder than finding out when the radar detector was invented no websites seem to list the infomation!

    i would have thought 1991 i'm sure i've read it somewhere,

  7. #7

    Default Re: info on radar and radar bands! also L,S,C,V BANDS!!

    Quote Originally Posted by laserblaster
    A mobile unit the laser gun can pinpoint a target in a lane of traffic, it takes less than half a second to get a reading wheras a radar can take 2-3 seconds. It can't be used from behind glass, requires a very steady hand, and at 1000 feet the beam is 3 feet wide, at 1 and 1/2 miles the beam is 2 lanes wide
    You can operate laser behind glass. Cops use the window to help
    keep the laser gun steady.

  8. #8
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    this is what valentine says about laser

    To measure speed, traffic laser sends out a beam of pulsed
    infrared light. The beam is tightly focused: at a range of
    1000 feet, it’s only about four feet wide.
    Infrared is invisible to the naked eye — the operator can’t
    see it and neither can you. But it is light and it behaves
    accordingly. It travels in straight lines. And it’s easily
    reflected.
    Traffic laser works as a rangefinder. It sends a pulse, then
    waits for the reflection from the target car. From the time
    needed for the pulse to go out and back, and from the speed
    of light, it calculates distances to the car. These pulses are
    sent frequently, up to 500 times a second. The changing
    distance to the target over time is speed.
    Laser can’t see over hills or through opaque objects. The
    laser beam must hit your car directly, line-of-sight from the
    laser gun, to measure speed. Under ideal conditions, it can
    read speed in less than one second.
    The pencil beam means that, in operation, laser is very
    different from radar. Radar cannot single out one vehicle in
    a pack, so the speed reading is usually attributed to the
    leader. The narrow laser beam reads only the vehicle it
    strikes.
    Laser’s narrow beam imposes significant limits on its use.
    It must be deliberately and carefully aimed. The operator
    can’t be moving. He must have a clear shot, preferably not
    through glass.
    So laser traps are always ambushes. The operator lies in
    wait. As with radar, he can’t read speed from the side. He
    must have oncoming and departing traffic. Look for a
    cruiser angled to the road, or broadside. Watch overpasses
    and entrance ramps. He will likely rest the laser gun on a
    partially-down side window to steady his aim. He will pick
    off traffic as it comes. Or goes.

    Details To Remember About Laser
    1. There is no moving laser.
    2. All laser encounters are like Instant-on radar; virtually
    no advanced warning.

    it isnt ment to be used through glass ! as it interferes line of sight with the reading!

    also the angles of the glass would reflect the laser!
    so generaly no they dont use it behind glass!

    even our safty camera teams dont use it behind glass!

  9. #9
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    generation 3 lidar guns can be shot through glass easily at a great distance

    Spoiler: show

    Radar Detectors-V1 & BEL v995
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  10. #10
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    Quote Originally Posted by laserblaster
    He must have a clear shot, preferably not
    through glass.

    it isnt ment to be used through glass ! as it interferes line of sight with the reading!

    also the angles of the glass would reflect the laser!
    so generaly no they dont use it behind glass!

    even our safty camera teams dont use it behind glass!
    Well, here are 2 kind of measuring with Lidars. A Lidar only isn't enough in Hungary, LEOs must prove the speeding with a record. That's why all Lidars are mounted together with videocams (and all radars are mounted together with cameras) here.
    The most common usage is from a tripod but some units are equipped to the passenger seat of a covert police car and they can measure through the glass easily. The only difference that the maximum distance of measuring is shorter in this case.
    Here are ProLaserII and ProLaserIII only. Some in-car units are linked with a GPS system and they could measure you when they're moving.

 

 

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