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  2. Amateur radio repeater - Wikipedia

    en.wikipedia.org/wiki/Amateur_radio_repeater

    An amateur radio repeater system consisting of a 70 cm repeater and a 2-meter digipeater and iGate. Coaxial cavity RF filter at 2 meter repeater An amateur radio repeater is an electronic device that receives a weak or low-level amateur radio signal and retransmits it at a higher level or higher power, so that the signal can cover longer ...

  3. Communication during the September 11 attacks - Wikipedia

    en.wikipedia.org/wiki/Communication_during_the...

    According to 9/11 Commission staff statement No. 17 [1] there were several communications failures at the federal government level during and after the 9/11 attacks. Perhaps the most serious occurred in an "Air Threat Conference Call" initiated by the National Military Command Center (NMCC) after two planes had crashed into the World Trade Center, but shortly before The Pentagon was hit.

  4. Radio repeater - Wikipedia

    en.wikipedia.org/wiki/Radio_repeater

    Amateur repeaters in the 144–148 MHz band usually use a 600 kHz (0.6 MHz) separation, in the 1.25-meter band use a 1.6 MHz separation, in the 420–450 MHz band use a 5 MHz separation, and in the 902–928 MHz band use a 25 MHz separation. Systems in the 450–470 MHz band use a 5 MHz separation with the input on the higher frequency.

  5. WPOZ - Wikipedia

    en.wikipedia.org/wiki/WPOZ

    WPOZ had a repeater in Daytona Beach, WEAZ 88.1 MHz, licensed to Holly Hill; this station was permitted in 1995 as WANX, signed on as a simulcast of WPOZ as WEAZ in 1998. The operation of WEAZ (like WLMS in Lacanto) would also interfere with the WPOZ power increase, as it operated on the first adjacent 88.1 FM channel of WPOZ.

  6. 2-meter band - Wikipedia

    en.wikipedia.org/wiki/2-meter_band

    The 2-meter amateur radio band is a portion of the VHF radio spectrum that comprises frequencies stretching from 144 MHz to 148 MHz [1] in International Telecommunication Union region (ITU) Regions 2 (North and South America plus Hawaii) and 3 (Asia and Oceania) [2] [3] and from 144 MHz to 146 MHz in ITU Region 1 (Europe, Africa, and Russia).

  7. Trunked radio system - Wikipedia

    en.wikipedia.org/wiki/Trunked_radio_system

    There is also nothing to prevent multiple groups in the same area from choosing the same channel, causing conflicts and 'cross-talk'. A trunked radio system is an advanced alternative in which the channel selection process is done automatically, so as to avoid channel conflicts and maintain frequency efficiency across multiple talkgroups.

  8. Coverage map - Wikipedia

    en.wikipedia.org/wiki/Coverage_map

    A coverage map may be produced to indicate the area in which a certain signal strength is delivered. [1] Even if it is 100% accurate (which it never is), a major factor on whether a signal is receivable depends very much on whether the receiving apparatus is sensitive enough to use a signal of that level.

  9. Frequency coordinator - Wikipedia

    en.wikipedia.org/wiki/Frequency_coordinator

    Frequency Coordination is required for a new filing. Major Modifications and Amendments that change or add frequencies, emissions, ERP, Output Power, Antenna Height, Ground Elevation, change location of Base, Fixed, Mobile or Control stations or number of Mobile units and any change to station class.