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REPEATERS

REPEATERS. SIERRA INTERMOUNTAIN EMERGENCY ASSOCIATION. WHY REPEATERS?. Extend the range of our low power portables and mobiles. Provides the means for communications throughout a geographic community. THE SIERA REPEATER.

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REPEATERS

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  1. REPEATERS SIERRA INTERMOUNTAIN EMERGENCY ASSOCIATION

  2. WHY REPEATERS? • Extend the range of our low power portables and mobiles. • Provides the means for communications throughout a geographic community.

  3. THE SIERA REPEATER • Located on Leviathan peak, about 30 miles south of Gardnerville at about 8900 ft. • Receives on 147.930 MHz • Requires a PL of 123 Hz • Transmits on 147.330 MHz, ERP 25 watts

  4. LEVIATHAN VIEWED FROM MONITOR PASS HIGHWAY

  5. GEORGE UEBELE AND WILL LEWIS JULY 29, 2005

  6. Leviathan Repeater building

  7. Leviathan equipment room

  8. SIERA repeater

  9. LEVIATHAN SOLAR PANELS

  10. LEVIATHAN LOOKING EAST

  11. LEVIATHAN LOOKING NORTHEAST

  12. LEVIATHAN LOOKING NORTH

  13. LEVIATHAN LOOKING WEST

  14. LEVIATHAN LOOKING SOUTH

  15. TARA REPEATER • Located on East Peak at about 9500 feet • Receives on 147.840 MHz • Sometimes requires a PL of 123 Hz • Transmits on 147.240 MHz

  16. East Peak Antenna Tower

  17. East Peak View of Lake Tahoe

  18. East Peak View of Lake Tahoe to North

  19. East Peak View of South Lake Tahoe

  20. East Peak View to Southeast towards Carson Valley

  21. East Peak View to East towards Carson Valley

  22. East Peak View to Northeast towards Carson City

  23. W7DI REPEATERS • Located on McClellan Peak, north of Carson City at about 7400 ft • Two repeaters linked together • Receives on 147.870 MHz • Requires PL of 123 Hz • Transmits on 147.270 MHz, ERP 100 watts • Receives on 446.250 MHz • Requires PL of 123 Hz • Transmits on 441.250 MHz, ERP 80 watts

  24. McClellan Peak Antenna Farm

  25. McClellan Peak North Side of Equipment Building April 13, 2011

  26. McClellan Peak W7DI Repeaters VHF in front on bottom UHF in back on top

  27. MINDEN REPEATER Receives 448.750 MHz - No PL Transmits 443.750 MHz - ERP 20 watts Linked to McClellan repeaters

  28. REPEATER REQUIREMENTS • Must be able to transmit and receive simultaneously • Requires two antennas or a duplexer • Requires a controller • Must meet Site Managers specifications

  29. DUPLEXERS • Duplexers allow you to transmit and receive simultaneously on a common antenna • Duplexers are made up of 4 or more cavities • A cavity passes a narrow bandwidth centered on its resonant frequency

  30. DUPLEXERS 147.930 147.930 147.330 147.330 r Transmitter 147.330 Receiver 147.930

  31. COAXIAL CABLE • Loss in coax cable increases with frequency • Larger cable has less loss than smaller TARA repeater has 410 ft of 7/8” Heliax with a loss of 1.85 db

  32. CONTROLLERS • Must be able to turn the repeater off and on • Must ID at required intervals • Needs a timeout timer • Other options: • Courtesy tones • Hang time • Announcements • Auxillary controls

  33. CONTROL OPERATOR • A control operator is required any time an amateur transmitter is in operation • For repeater operation, the FCC allows remote control. The repeater control operator(s) can monitor and control its operation by some form of control link from one or more distant locations. • A radio control link uses an auxiliary frequency to control the repeater. Auxiliary frequencies must be above 222.15 MHz • Control codes should be known only by the licensee and control operators

  34. AUTOMATIC CONTROL • (Automatic control) the use of devices and procedures for control of a station when it is transmitting so that compliance with the FCC Rules is achieved without the control operator being present at a control point. §97.3 (a)(6) • In the event of improper use of the machine, the licensee is responsible for correcting the problem as soon as practicable and for making sure that the problem will not happen again (ARRL rule book) • Although no control operator is required to be present at a control point while the repeater is operating under automatic control, it is still the station licensee’s responsibility to see that the repeater operates properly at all times (ARRL rule book)

  35. FREQUENCY MODULATION • Frequency modulation is the process of using an audio signal to cause the RF carrier frequency to swing up and down • The audio level determines how far the RF carrier swings • The ideal audio level for ham radios will cause the frequency to deviate by ±5 KHz

  36. COMMON PROBLEMS • Improper modulation • Low audio levels will result if deviation is less than ± 5KHz • Audio levels exceeding ± 5KHz can result in distortion • Radios and microphones vary in sensitivity

  37. COMMON PROBLEMS • Not enough power • The RF signal into the repeater is not enough to “quiet” the receiver. • There will be background noise or you may not “hold” the repeater • Yelling into the microphone will usually not improve your signal if you have low power into the repeater • Most repeaters “talk out” further than they can “hear”

  38. PUBLIC SERVICE • §97.1 Basis and purpose (of amateur radio) • (a) Recognition and enhancement of the value of the amateur service to the public as a voluntary noncommercial communication service, particularly with respect to providing emergency communications. • Our ability to have repeaters located in public facilities is because of agreements with public officials to provide these services.

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