DISH Wireless L.L.C. 12/11/2023 - Laserfiche WebLink

WESTERN WASHINGTON COOPERATIVE INTERFERENCE COMMITTEE WWCIC ENGINEERING STANDARD #6 REV. C (02-97) FOR RADIO TRANSMITTING AND RECEIVING DEVICES AND FM BROADCAST All communications fixed transmitter installations shall employ isolators or alternative techniques meeting the same criteria to minimize spurious radiation and intermodulation products. Additional filtering may be required according to frequency and interconnect devices as listed below. As the industry progresses, superior devices may be available and installed. The following engineering standards will be observed: Transmitters in the 29.8 to 54 MHz range shall have a low pass filter, band pass filter or cavity providing a minimum of 30 dB attenuation removed 1.0 MHz from the operating frequency. Transmitters in the 66 to 88 MHz range shall have at least 25 dB of isolation followed by a band pass cavity providing at least 20 dB of attenuation 1.0 MHz removed from the operating frequency. Transmitters in the 88 to 108 MHz range operating at a power level of 350 watts or less shall have at least 25 dB of isolation followed by a band pass cavity providing at least 35 dB of attenuation 1.0 MHz from the operating frequency. Transmitters in the 88 to 108 MHz range at power levels above 350 watts shall have a band pass cavity providing at least 25 dB of attenuation 1.4 MHz from the operating frequency. Transmitters in the 130 to 225 MHz range shall have at least 50 dB of isolation followed by a low pass filter and band pass cavity with a minimum of 15 dB of attenuation 1.0 MHz removed from the operating frequency. Transmitters in the 400 to 470 MHz range shall have at least 50 dB of isolation followed by a low pass filter and band pass cavity with a minimum of 15 dB of attenuation 2.0 MHz removed from the operating frequency. Transmitters in the 806 to 990 MHz range shall have at least 50 dB of isolation followed by a low pass filter or a band pass filter with a minimum of 15 dB of attenuation 10 MHz removed from the operating frequency and 40 dB of attenuation at 20 MHz. A band pass cavity/filter or crystal filter is recommended at the input of all receivers. Its purpose is to protect against RF energy "off frequency" from mixing in a non- linear device such as the first RF amplifier in a receiver which can re-radiate causing interference. The band reject duplexer (cross notch duplexer) may not be used without the use of cavities or isolators.