Agenda Packets - 2007/04/02 (2) - Laserfiche WebLink

Home Browse Search

3 instrumentation used shall have been calibrated within the six-month period prior to the testing. 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. 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. 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 the Fire Chief’s 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 nearest Anoka County 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. Alternative in-building amplification systems that do not involve broadband pass band filters will be accepted provided that similar testing can be demonstrated. 3.1.2 Talk-out to the Regional Radio System Testing 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 Anoka County 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. 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