Goto Section: 15.250 | 15.252 | Table of Contents
Revised as of October 1, 2020
Goto Year:2019 |
§ 15.251 Operation within the bands 2.9-3.26 GHz, 3.267-3.332 GHz,
3.339-3.3458 GHz, and 3.358-3.6 GHz.
(a) Operation under the provisions of this section is limited to
automatic vehicle identification systems (AVIS) which use swept
frequency techniques for the purpose of automatically identifying
(b) The field strength anywhere within the frequency range swept by the
signal shall not exceed 3000 microvolts/meter/MHz at 3 meters in any
direction. Further, an AVIS, when in its operating position, shall not
produce a field strength greater than 400 microvolts/meter/MHz at 3
meters in any direction within ±10 degrees of the horizontal plane. In
addition to the provisions of § 15.205, the field strength of radiated
emissions outside the frequency range swept by the signal shall be
limited to a maximum of 100 microvolts/meter/MHz at 3 meters, measured
from 30 MHz to 20 GHz for the complete system. The emission limits in
this paragraph are based on measurement instrumentation employing an
average detector. The provisions in § 15.35 for limiting peak emissions
(c) The minimum sweep repetition rate of the signal shall not be lower
than 4000 sweeps per second, and the maximum sweep repetition rate of
the signal shall not exceed 50,000 sweeps per second.
(d) An AVIS shall employ a horn antenna or other comparable directional
antenna for signal emission.
(e) Provision shall be made so that signal emission from the AVIS shall
occur only when the vehicle to be identified is within the radiated
field of the system.
(f) In addition to the labelling requirements in § 15.19(a), the label
attached to the AVIS transmitter shall contain a third statement
regarding operational conditions, as follows:
* * * and, (3) during use this device (the antenna) may not be
pointed within ±** degrees of the horizontal plane.
The double asterisks in condition three (**) shall be replaced by the
responsible party with the angular pointing restriction necessary to
meet the horizontal emission limit specified in paragraph (b).
(g) In addition to the information required in subpart J of part 2, the
application for certification shall contain:
(1) Measurements of field strength per MHz along with the intermediate
frequency of the spectrum analyzer or equivalent measuring receiver;
(2) The angular separation between the direction at which maximum field
strength occurs and the direction at which the field strength is
reduced to 400 microvolts/meter/MHz at 3 meters;
(3) A photograph of the spectrum analyzer display showing the entire
swept frequency signal and a calibrated scale for the vertical and
horizontal axes; the spectrum analyzer settings that were used shall be
labelled on the photograph; and,
(4) The results of the frequency search for spurious and sideband
emissions from 30 MHz to 20 GHz, exclusive of the swept frequency band,
with the measuring instrument as close as possible to the unit under
[ 54 FR 17714 , Apr. 25, 1989; 54 FR 32340 , Aug. 7, 1989]
Goto Section: 15.250 | 15.252
Goto Year: 2019 |
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