Pennsylvania Code
Title 67 - TRANSPORTATION
Part I - Department of Transportation
Subpart A - Vehicle Code Provisions
Article VI - Operation of Vehicles
Chapter 105 - MECHANICAL, ELECTRICAL AND ELECTRONIC SPEED-TIMING DEVICES
Subchapter B - ELECTRONIC DEVICES (RADAR)
Section 105.15 - Calibration and testing procedure
Universal Citation: 67 PA Code ยง 105.15
Current through Register Vol. 54, No. 44, November 2, 2024
(a) General. An electronic device shall be calibrated and tested as follows:
(1)
Power output.
Relative power output shall be measured in the following manner:
(i) Adjust dc power supply to 13.6
vdc.
(ii) With equipment still
connected as in Appendix A, Figure 2, position (1), position antenna system
along each axis for maximum coupling. Simultaneously increase attenuation to
avoid overloading the thermister amount.
(iii) Adjust microwave variable attenuator
for maximum attenuation and then calibrate microwave power meter.
(iv) Reduce attenuation until microwave power
meter reads 0 dB.
(v) Calculate
power output taking into consideration the gain of the horn, and attenuation of
the microwave variable attenuator, added algebraically with the power level
indicated on the power meter.
Example:
|
Attenuator |
33.6 dB |
|
Power Meter Reading |
0.0 dB |
|
______ |
|
|
33.6 dB |
|
|
Gain of Horn |
-16.7 dB |
|
Relative Power |
______ |
|
16.9 dB |
= 48.98. |
(2)
Transmitted frequency.
Transmitted frequency shall be measured in the following manner:
(i) Adjust variable dc power supply to 13.6
vdc.
(ii) With the equipment
connected as in Appendix A, Figure 2, position (2) adjust the microwave
variable attenuator for a stable readout on frequency counter.
(iii) Record transmitter frequency as
indicated on the microwave frequency counter. Frequency shall be within .2% of
licensed frequency.
(iv) Vary the
applied voltage from 11 vdc to 14 vdc. Frequency shall remain within .2% of
licensed frequency.
(3)
Stability test. The stability test shall be conducted in the
following manner:
(i) Adjust variable dc power
supply to 13.6 vdc.
(ii) Connect
equipment as in Appendix A, Figure 2, position (3).
(iii) Adjust square wave output of function
generator to the switching level of the pin diode switch. While observing the
frequency counter, adjust frequency of function generator to 1726 Hz (X-Band)
or 3961 Hz (K-Band) or 5692 Hz (Ka-Band).
(iv) Vary applied dc voltage from 11 vdc to
14 vdc while observing indicated speed on device being tested. Indicated speed
may not vary.
(4)
Relative sensitivity. Relative sensitivity shall be measured
in the following manner:
(i) Adjust variable
dc power supply to 13.6 vdc.
(ii)
Connect equipment as in Appendix A, Figure 2, position (3).
(iii) Adjust range control if applicable on
electronic device for maximum range.
(iv) Adjust square wave output of function
generator, to switching level of pin diode modulator. While observing frequency
counter, adjust frequency of function generator so that device being tested
indicates 55 mph.
(v) Slowly
increase attenuation of microwave variable attenuator, until speed reading of
55 mph of device being tested becomes erratic.
(vi) Readjust position of device for maximum
coupling.
(vii) Repeat steps in
subparagraphs (v) and (vi) until no further increase is possible, without
losing display. Maximum coupling is imperative.
(viii) Calculate relative sensitivity of
device being tested, taking into consideration attenuation or gain of each
component in the microwave path. The reflected signal passes through devices
two times therefore values shall be multiplied by two.
Example:
| Gain of Horn | 16.7 dB x 2 | +33.4 dB |
| Attenuation | 33 dB x 2 | -66 dB |
| Relative Sensitivity | -32.6 dB |
(5)
Accuracy test. The
accuracy test shall be conducted in the following manner:
(i) Adjust variable dc power supply to 13.6
vdc.
(ii) Connect equipment as in
Appendix A, Figure 2, position (3).
(iii) Adjust square wave output of function
generator, to switching level of pin diode modulator. While observing frequency
counter, adjust function generator for an indicated speed of 55 mph.
(iv) Adjust microwave variable attenuator and
range control for stable display.
(v) While observing the frequency counter,
adjust the function generator to each test frequency. Note and record the speed
indicated on the electronic device display. Each test frequency shall produce
the correct speed in mph within the limits of +0, -1 mph.
Test Frequencies (in Hz)
| X Band | K Band | Ka Band | Indicated Test Speed mph |
| 628 | 1440 | 2070 | 20 |
| 785 | 1801 | 2588 | 25 |
| 942 | 2161 | 3105 | 30 |
| 1099 | 2521 | 3622 | 35 |
| 1256 | 2881 | 4140 | 40 |
| 1412 | 3241 | 4657 | 45 |
| 1569 | 3601 | 5175 | 50 |
| 1726 | 3961 | 5692 | 55 |
| 1883 | 4321 | 6210 | 60 |
| 2040 | 4681 | 6727 | 65 |
| 2197 | 5042 | 7246 | 70 |
| 2354 | 5402 | 7762 | 75 |
| 2511 | 5762 | 8281 | 80 |
| 2668 | 6122 | 8797 | 85 |
| 2825 | 6482 | 9316 | 90 |
| 2982 | 6842 | 9832 | 95 |
| 3139 | 7202 | 10351 | 100 |
| 3296 | 7562 | 10867 | 105 |
| 3453 | 7922 | 11385 | 110 |
| 3610 | 8283 | 11902 | 115 |
| 3767 | 8643 | 12420 | 120 |
| 3924 | 9003 | 12937 | 125 |
| 4081 | 9363 | 13455 | 130 |
| 4238 | 9723 | 13972 | 135 |
| 4394 | 10083 | 14490 | 140 |
(6)
Tuning fork test. The
tuning fork test shall be conducted in the following manner:
(i) Connect the microphone, ac voltmeter and
frequency counter as depicted in Appendix A, Figure 2.
(ii) Strike the tuning fork on a block of
wood and hold the vibrating tuning fork close to the microphone.
(iii) Adjust the gain of the audio amplifier
for a stable display on the frequency counter.
(iv) Note the displayed frequency on the
frequency counter and convert it into miles per hour. The calculated speed
shall be the same as that indicated on the tuning fork or within 1%. The tuning
fork shall be at room temperature, or approximately 70° F., when this
measurement is taken.
(v) Strike
the tuning fork on a block of wood and hold it close to the device antenna. The
indicated speed shall be stable, and shall be that of the tuning
fork.
(7)
Rejection of extraneous RF fields.
(i) Adjust variable dc power supply to 13.6
vdc.
(ii) Position the base loaded
antenna 1 meter from the radar assembly.
(iii) Activate the 4 watt signal source,
modulated at 100%, 1726 Hz (X-Band) or 3961 Hz (K-Band) or 5692 Hz
(Ka-Band).
(iv) There may be no
readout on the electronic device indicator, related to the extraneous RF
field.
(b) Maintenance work-order. A maintenance work-order containing the following information shall be completed and forwarded to the Communications Division:
(1) Serial number of
the electronic device.
(2) Work
performed and date of same.
(3)
Original complaint, if any.
(4)
Actual repairs performed, if any.
(5) Amount of time taken to repair
unit.
(6) Manufacturer's stock
number of all equipment replaced.
(7) Total labor cost.
(8) Individual part prices for all equipment
replaced.
(9) The name and address,
class, serial number and expiration date of the operator's license of the
individual conducting the test. The testing individual shall also sign and date
the maintenance work order. Maintenance performed shall conform with FCC rules
and regulations pertaining to radio location devices.
(c) Certificates of accuracy. These forms, provided by the Department, shall be filed for each electronic device calibrated and tested.
(1) Original shall be filed at the State
Police station.
(2) One duplicate
copy shall be retained by the maintenance and calibration station for at least
2 years.
(3) One duplicate copy
shall be forwarded to the Communications Division, State Police.
(4) One duplicate copy shall accompany the
electronic device.
(5) A duplicate
copy, executed and signed in the same manner as the original, has the same
force and effect as the original.
(d) Electronic device-radar-calibration. Technical data forms provided by the State Police Communications Division, shall be filed for each electronic device calibrated and tested.
(1) One original shall
be forwarded to the Communications Division, State Police.
(2) One duplicate copy shall be retained by
the maintenance and calibration station for at least 2 years.
(3) A duplicate copy, executed and signed in
the same manner as the original, has the same force and effect as the
original.
This section cited in 67 Pa. Code § 105a.4 (relating to system and speed timing device use and certification).
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