🚀 go-pugleaf

In sci.electronics, pfluegerm@gtephx.UUCP writes:
p>
p>I believe radar guns have about a 3 degree beamwidth.  At 1000'  (1/5
p>mile, roughly the detection range), the radar beamwidth is 105'. 
p>Consider the angles and the radar is illuminating a LONG stretch of
p>the oncoming lane.

The specs on the two that I have are much wider than 3 deg., regardez:




MPH Industries K-55 radar unit


                         UNIT

OPERATING SPEED:   Patrol-   20MPH to 55MPH
                             (above 55/below 20 available on request)

TARGET SPEED:      20MPH minimum to maximum 209MPH closing speed
                   20MPH to 100MPH while patrol is stationary

SPEED VALIDATION:  target speed 50MPH:  100 comparisons in 1/8 sec.
                   target speed 70MPH:  140 comparisons in 1/8 sec.

RFI PROTECTION:    when excessive RFI is present, no readings will be
                   displayed

CALIBRATION ADJ:   NONE- fixed

TIME BASE:         Crystal oscillator +- 5 %

LOCK TIME:         Instantaneous

ACCURACY:          +- 1MPH Absolute


                        ANTENNA

ANTENNA TYPE:      Circularly polarized conical horn

OPERATING FREQ:    X-Band: 10.525 GHz +-21.05MHz
                   K-Band: 24.150 GHz +-48.3MHz

OUTPUT POWER       X-Band:  Nominal 13-30mW    Maximum 50mW
                   K-Band:  Nominal 12-50mW    Maximum 95mW

RADIATED PWR DEN:  < 1mW/cm^2 @ 5cm (in accordance with microwave oven stds.)

BEAM WIDTH:        X-Band:  maximum 18 degrees
                   K-Band:  maximum 15 degrees

SIDE LOBES:        24dB down from main beam

RANGE:             2500 feet for avg vehicle size.  Range varies by size of
                   vehicle, terrain, weather.




                AND THE EVER POPULAR Ka-BAND RADAR UNIT
(made by Zellwager Uster AG [Switzerland] for Traffic Monitering Technologies
                         of Friendswood Texas)

                              UNIT

MEASURING DIRECTION:  Oncoming traffic

MEASURING RANGE:      15MPH to 155MPH

MEASURING ACCURACY:   <= 100MPH   +- 1MPH
                      > 100MPH    +- 1%

ELECTRONIC FLASH:     170W/340W
                      
           RECHARGE TIME:  170W    0.9 sec.
                           340W    1.8 sec.



                             ANTENNA

TRANSMIT FREQUENCY:       34.3 GHz +- 100MHz

TRANSMITTED POWER:        0.5mW MAXIMUM

TYPE OF ANTENNA:          parabolic reflector

HALF-PWR BEAM WIDTH:      5 degrees horizontal
                          5 degrees verticle

SECONDARY LOBE ATTEN:     > 20dB

MEASURING ANGLE TO
DIRECTION OF TRAVEL:      22 degrees

RANGE:                    Designed for 50 feet with downward transmission
                          @ 22 +- 3 degrees beam width.  Beam makes 5 degree
                          angle with ground at 50 feet.