With or without an in-building radio system, it will be the building owner’s responsibility to have the regional radio system performance tested to ensure that two-way coverage on each floor of the building is a minimum of 90% of the total floor area and the critical areas designated.
(A) Talk-in from the regional radio system coverage testing.
(1) The talk-in coverage testing process shall be the same for buildings with and without in- building amplification systems.
(2) During test measuring, the center of the test equipment receive antenna shall be between 30 and 36 inches above the floor.
(3) On each floor of a building to be tested, the floor space, except for designated critical areas, shall be divided into square or rectangular areas of approximately the same size and shape. Each floor shall have at least ten grid areas; however, the maximum size of grid areas shall not exceed 2,500 square feet. In buildings with support columns laid out in a grid, the corners of the each grid may be arranged at the columns for ease in identifying grid comers while testing is in progress. In buildings, such as a warehouse, with large open areas, tests shall be conducted near the center of each grid although the exact center may not be easily accessible due to the location of large machinery, storage racks, and the like. In buildings with divided office spaces, with or without floor to ceiling partitions, tests shall be conducted in an office at or near the center of a grid. In buildings with a large open area and an attached two-story, split level office or other area, the lower level of the two-story, split level attachment shall be considered as an extension of the large open area.
(4) In multi-story buildings and parking ramps, testing shall begin at the lowest level, including any subgrade level(s), and continue up one floor at a time. In-building amplification may only be required on the lowest level or levels of a multi-story building or parking ramp.
(5) Average radio signal field strength shall be measured and recorded in each grid, and in each designated critical area defined above. Average field strength may be obtained through use of an instantaneous measuring instrument and a computer that samples the actual field strength at very short time intervals and averages the sample values. As an alternative, a field strength measuring instrument with an analog or digital readout of average field strength may also be used. Measurements shall be made while the measuring instrument is moved over a distance of four to ten feet. If the average field strength varies over the measurement path, the lowest (most negative) value shall be recorded. The test instrumentation used shall have been calibrated within the six-month period prior to the testing.
(6) The percentage of area passed shall be calculated as 100 times the result of dividing the number of grids and critical areas that are at least at -93 dBm or 1% BER by the total number of grids and critical areas tested.
(7) The donor antenna in an in-building amplification system may receive up to 87 800 MHZ radio frequencies of approximately equal field strength from the regional system, plus some others of approximately equal field strength from other radio systems. At any time, the donor antenna may be receiving at least 60 radio frequencies of approximately equal level in the pass band ranges. For that reason, it shall be assumed that the output level of talk-in amplifiers will be at + 3.2 dBm per channel maximum. Therefore, grid and critical areas tests shall be conducted while the headend amplifier is disconnected and a signal of + 3.2 dBm is inserted into the connector downstream from the headend amplifier.
(8) Any in-building talk-in amplification system shall have pass band filters before the input to the first (headend) amplifier that shall pass 806 to 817 MHZ and 821 to 824 MHZ only. In the future, within six months after notification by the Fire Chief or his designee, the pass band filter frequency range shall be changed in accordance with instructions, or an additional pass band filter for 700 MHZ band frequencies shall be added. When the donor antenna is installed, the average signal level received on the Hennepin East site control channel shall be measured at the antenna connector. A signal at that average received signal level shall be inserted into the cable to the headend amplifier and filter while the output level of the headend amplifier is measured, and the output level of the amplifier shall be set at + 29 + 1 dBm.
(9) Alternative in-building amplification systems that do not involve broadband pass band filters will be accepted provided that similar testing can be demonstrated.
(B) Talk-out to the regional radio system testing.
(1) With an in-building amplification system, the talk-out (to the regional 800 MHZ radio system) shall be measured at the same grid and critical area locations as the talk-in measurements were made. The measurements shall be made using a three-watt portable radio with a well-charged battery to transmit into the in-building radio system while field strength is measured out of the connector that is normally attached to the donor antenna. To pass, the field strength at the donor antenna shall be the measured value at the connector plus the donor antenna gain and minus a free space loss factor. The free space loss factor shall be -93 dB for a distance of one mile to the nearest Hennepin East base radio location, adjusted by 6 dB each time the distance is halved or doubled. The acceptable range for passing shall be between -65 and -95 dBm.
(2) (a) Gain values of all amplifiers shall be measured and the test measurement results shall be kept on file with the building owner so that the measurements can be verified each year during the annual tests.
(b) In the event that the measurement results become lost, the building owner will be required to rerun the acceptance test to reestablish the gain values.