CARA

Calgary Amateur Radio Association

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'Temporary Install' Mobile Radios for Events

CARA has Two ICOM IC-2720H 'Mobile' 50 Watt 12 VDC Radios for Temporary Installs

Questions, suggestions, or if these radios need servicing:   VA6RPL@techworld.ca

CARA's 'Temporary Install" 'back pack' radios are kept at the VE6AO station at the Calgary Sports Car Club. 

These radios are configured for use at activities and events by certified amateur radio operators.  Common scenarios:

  • A radio operator is stationed in a vehicle, other than their own, for the duration of an event, possibly all day or for an entire weekend.  Examples of event vehicles could be ambulance, tow truck, bus, or transport truck.  It may be much easier to do an install of a CARA "temporary install radio" into the new vehicle, rather than pull their own radio out of their own car.
  • The radios might be used by amateur radio operators, in their own vehicle, who do not possess their own radio equipment.
  • An extra radio may be needed for monitoring / transceiving if there are three or more additional event channels.

The main features of the ICOM IC-2720H features include:

  • dual band, VHF and UHF, FM and AM
  • dual channel, each capable of VHF and UHF 
  • cross band repeat
  • transmit power selections of Low (5 Watts), Medium (25 Watts), and High (50 Watts)
  • scanning among designated channels
  • sorry, no built-in APRS capability

In particular, a very useful feature of the ICOM IC-2720H features is "cross banding".  When set to cross-band mode, this allows the amateur radio operator to step away from the vehicle with a low power 5 watt handheld radio and maintain wide-area contact through the nearby higher power IC-2720 vehicle-mounted mobile radio.  A wide area contact could be "net control" which may be many kilometres away, far beyond a hand-held radio's range.  A real world example could be a radio operator stationed in an ambulance for the day.  If the ambulance crew has to climb down a ravine to treat and extricate an injured party in a crashed vehicle, the radio operator would set the IC-2720 to 'cross-band' mode, bring his/her handheld programmed to the appropriate UHF frequency, and accompany the EMT's down into the ravine, thereby maintaining constant contact with far-away net control.

These IC-2720 mobile radios are also programmed, configured, and ready for regular net control service in the CARA Communications Trailer.  An AWG 12/2 power pigtail is included in each radio kit with an SAE connector at one end and Anderson 30A Power Pole connectors at the other end for connection to the comm trailer Rig Runner.


    Laminated Reference Cards Affixed to Radio Bread Board

    List of Pre-programmed Event Channels:

    • Calling
    • Repeater
    • UHF Cross Band

    How to Turn Cross Banding On/Off


    What's in the Back Pack

    • ICOM IC-2720H radio, with 1 meter long AWG 12/2 red/black (extended) power cord with SAE connector (positive/red prong is male).  Fuse holder with 20 Amp ATC fuse is located on negative/black power cable. 
    • 8 meter AWG 12/2 red/black copper power cord to connect radio directly to the vehicle battery.  Silicone wire cladding stays flexible in winter conditions.  SAE plug at one end and alligator battery clips at other end.  Fuse holder with 20 Amp ATC fuse is located on positive/red power cable next to positive/red alligator battery clip.  This is a long cable to allow for the extra distance required when the radio is set up in the back of an ambulance.
    • 1 meter AWG 12/2 for connecting radio to the comm trailer Rig Runner.  SAE connector at one end and Anderson 30A Power Pole connectors at other end.  Fuse holder with 20 Amp ATC fuse is located on positive/red power cable next to Anderson Power Pole connectors.
    • Spare ATC 20 Amp automotive fuses, to comply with standard ATC fuses throughout comm trailer.
    • Larsen 5/8 wave mag-mount VHF/UHF antenna with 3.5 metre co-ax cable with PL-259 connector.
    • RG-58AU 5 metre co-ax antenna extension cord with PL-259 and SO-239 connectors.
    • Zip ties and side cutters for placement and removal of power wires and coax cables.

    • Hand tool for spreading SAE male prong.

    • RT Systems USB-29A programming cable for IC-2720 radio.


      Duo-Tang Plastic Folder in Back Pack With Hard Copy Reference Information

      • The Duo-Tang contains hard copies of the documents listed above in the USB memory stick. some of which are laminated.

      Considerations Regarding Connecting a 50 Watt Dual Channel Mobile Radio Directly to the Vehicle Battery vs. to the Cigarette Lighter Power Port

      • Please be considerateUnless in your own vehicle, do not use a 'cigarette lighter' style socket as a power source when operating a 50 Watt mobile radio in any vehicle, regardless of any posted Wattage capacity beside the power port.  The wiring behind that cigarette lighter plug may not be adequate to carry the amperage the radio draws at Medium and High (12A) Tx power, resulting in blown fuses or electrical fires.
      • The cigarette lighter plug may cause voltage drops.  
      • Unshielded ignition noise may be superimposed onto transmit or receive audio.
      • An ambulance is a mission critical resource and its ability to communicate with net control can mean the difference between life and death.  

      The ambulance is not ready to head out on to the course until the 50 Watt amateur radio on board is capable of sustained 50 Watt (high power) send and receive, including while in cross band mode for the VHF side of the radio.  

      * It is not necessary to run the radio on high power all the time.  Start with LOW or MED.  But it 'IS' necessary for the radio to be set up and 'READY' to transmit with HIGH power in case the need arises.

      When at the far end of a course, a long distance from net control, amid high terrain, rain, fog, snow, and sleet conditions, the radio system must be as functional as possible.  

      The middle of an accident scene is not the time for the ambulance radio operator to find out that a Low or Medium power mode connected to a lower wattage cigarette lighter power supply won't propagate far enough.  It's not the time to start stringing the power harness out to the vehicle battery.



      Images

      << All album photos 11/12 photos
      USB Solid State Drive With Soft Copies of Documents for CARA "Temporary Install" Mobile Event Radio.


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