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REPEATERS SIERRA INTERMOUNTAIN EMERGENCY ASSOCIATION.

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Presentation on theme: "REPEATERS SIERRA INTERMOUNTAIN EMERGENCY ASSOCIATION."— Presentation transcript:

1 REPEATERS SIERRA INTERMOUNTAIN EMERGENCY ASSOCIATION

2 WHY REPEATERS? 1.Extend the range of our low power portables and mobiles. 2.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 MHz Requires a PL of 123 Hz Transmits on 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 MHz Sometimes requires a PL of 123 Hz Transmits on 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 MHz Requires PL of 123 Hz Transmits on MHz, ERP 100 watts Receives on MHz Requires PL of 123 Hz Transmits on MHz, ERP 80 watts

24 McClellan Peak Antenna Farm

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

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

27 MINDEN REPEATER Receives MHz - No PL Transmits 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 r Transmitter Receiver

31 COAXIAL CABLE COAX TYPE ATT/100 FEET AT 2 METERS POWER OUT WITH 100 WATTS IN ATT/100 FEET AT 70 CENTIMETERS POWER OUT WITH 100 WATTS IN COST/FT RG586 db25 watts9 db13 watts0.30 RG81.5 db71 watts3 db50 watts1.00 1/2" Heliax.8 db83 watts1.4 db72 watts3.00 7/8" Heliax.45 db90 watts.8 db83 watts7.00 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: o Courtesy tones o Hang time o Announcements o 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 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 licensees 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 o Low audio levels will result if deviation is less than ± 5KHz o Audio levels exceeding ± 5KHz can result in distortion o Radios and microphones vary in sensitivity

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

38 PUBLIC SERVICE §97.1Basis 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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