amateur radio technician class element 2

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Amateur Radio Technician ClassElement 2

• ELEMENT 2 SUBELEMENTS

• T1 - FCC Rules, station license responsibilities• T2 - Control operator duties• T3 - Operating practices• T4 - Radio and electronic fundamentals• T5 - Station setup and operation• T6 - Communications modes and methods• T7 - Special operations• T8 - Emergency and Public Service Communications• T9 - Radio waves, propagation, and antennas• T0 - Electrical and RF Safety

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Special operations T7A

Radio direction finding• Radio direction finding is a method used to

locate sources of noise interference or jamming.

A directional antenna would be the most useful for a hidden transmitter hunt.

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• A good thing to have when operating a hand-held transceiver away from home are one or more fully charged spare battery packs.

• An amplifier would probably not be very useful to include in an emergency response kit.

Operating in the field

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Operating in the field (cont)

You can make the signal from a hand-held radio stronger when operating in the field by using an external antenna instead of the rubber-duck antenna.

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Operating in the field (cont)

• A combination headset and microphone would be a good thing to have when operating from a location that includes lots of crowd noise.

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Radio control

• The maximum power allowed when transmitting telecommand signals to radio controlled models is 1 watt.

• The station identification requirement when sending commands to a radio control model using amateur frequencies is a label indicating the licensee's call sign and address affixed to the transmitter.

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Contests• Contesting is a

popular operating activity that involves contacting as many stations as possible during a specified period of time.

• A grid locator is a letter-number designator assigned to a geographic location.

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Special operations T7B

Satellite operation, split frequency operation, operating protocols• The class of license required to use

amateur satellites is any amateur whose license allows them to transmit on the satellite uplink frequency.

• The minimum amount of power needed to complete the contact is the power that you should use to transmit when using an amateur satellite.

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Satellite operation, split frequency operation, operating protocols (cont)

• Something you can do when using an amateur radio satellite is talk to amateur radio operators in other countries.

• A satellite beacon is a signal that contains information about a satellite.

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Satellite sub bands

• A satellite sub-band is a portion of a band where satellite operations are permitted.

• The satellite sub-band on 70-CM is 435 to 438 MHz.

Orbit calculation

• You should use a satellite tracking program to determine when you can access an amateur satellite.

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Doppler shift• Doppler shift is a change in signal

frequency caused by motion through space.

LEO• The initials, LEO, tell you that the

amateur satellite is in a Low Earth Orbit (LEO).

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Special event stations

• A special event station is a temporary station that operates in conjunction with an activity of special significance.

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AMSAT• AMSAT is the name of the group

that coordinates the building and/or launch of the largest number of amateur radio satellites.

ISS communications• Any amateur with a Technician or higher class license may make contact with an astronaut on the International Space Station using

amateur radio frequencies.

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Emergency and Public Service Communications T8A

FCC declarations of an emergency• The information included in an

FCC declaration of a temporary state of communication emergency is any special conditions and rules to be observed during the emergency.

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FCC declarations of an emergency (cont)

• If you are in contact with another station and an emergency call is heard you should stop your contact immediately and take the emergency call.

• The restrictions on amateur radio communications after the FCC has declared a communications emergency are that you must avoid those frequencies dedicated to supporting the emergency unless you are participating in the relief effort.

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FCC declarations of an emergency (cont)

• An FCC declaration of a communications emergency is legally required to restrict a frequency to emergency-only communication.

• No station has exclusive use of a frequency if the FCC has not declared a communication emergency.

• If you hear someone reporting an emergency you should assume the emergency is real and act accordingly.

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FCC declarations of an emergency (cont)• The appropriate way to initiate an emergency call on

amateur radio is by saying "Mayday, Mayday, Mayday" followed by "any station come in please“ and identify your station.

• Penalties for making a false emergency call:You could have your license revokedYou could be fined a large sum of moneyYou could be sent to prison

• Emergency communications has priority at all times in the Amateur Radio Service.

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Use of non-amateur equipment and frequencies, use of equipment by unlicensed persons

• Priority must be given at all times and on all frequencies to stations providing emergency communications.

• When specially authorized by the FCC, or in an actual emergency, amateur stations are allowed to communicate with stations operating in other radio services.

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Tactical call signs

• One reason for using tactical call signs such as "command post" or "weather center" during an emergency is that they are more efficient and help coordinate public-service communications.

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Emergency and Public Service Communications T8B

Preparation for emergency operations• To be prepared for an emergency situation where

your assistance might be needed, you can:Check at least twice a year to make sure you have all of your emergency response equipment and know where it isMake sure you have a way to run your equipment if there is a power failure in your areaParticipate in drills that test your ability to set up and operate in the field

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Preparation for emergency operations (cont)

• The following could be used as an alternate source of power to operate radio equipment during emergencies: The battery in a car or truck A bicycle generator A portable solar panel

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Preparation for emergency operations (cont)

• In a genuine emergency you may use any means at your disposal to call for help on any frequency.

This may include using non-amateur frequencies or equipment to call for help in a situation involving immediate danger to life or property.

This may include using a modified amateur radio transceiver to transmit on the local fire department frequency.

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RACES/ARES• The primary function of RACES

in relation to emergency activities is RACES organizations are restricted to serving local, state, and federal government emergency management agencies.

• The primary function of ARES in relation to emergency activities is ARES supports agencies like the Red Cross, Salvation Army, and National Weather Service.

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RACES/ARES (cont)

• You must register with the responsible civil defense organization before you can participate in RACES activities.

• You must have an amateur radio license before you can join an ARES group.

Safety of life and property

• You may use your amateur station to transmit a "SOS" or "MAYDAY" signal when there is immediate threat to human life or property.

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Using ham radio at civic events

• Casual conversation between stations during a public service event should be avoided because idle chatter may interfere with important traffic.

Compensation prohibited

• If a reporter asks to use your amateur radio transceiver to make a news report you should advise them that the FCC prohibits such use.

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Emergency and Public Service Communications T8C

Net operations, interfacing with public safety officials

• To minimize disruptions to an emergency traffic net once you have checked in do not transmit on the net frequency until asked to do so by the net control station.

• Emergency traffic has the highest priority.

• Personal information concerning victims should not be transmitted over amateur radio frequencies during emergencies.

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Responsibilities of the net control station

• A strong and clear signal is of primary importance for a net control station.

• If someone breaks in with emergency traffic the net control station should stop all net activity until the emergency has been handled.

• If a large scale emergency has just occurred and no net control station is available you should open the emergency net immediately and ask for check-ins.

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Message handling

• The name of the person originating the message must be included when passing emergency messages.

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Message handling (cont)

• One way to reduce the chances of casual listeners overhearing sensitive emergency traffic is to pass messages using a non-voice mode such as packet radio or Morse code.

• The preamble of a message is the information needed to track the message as it passes through the amateur radio traffic handling system.

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Message handling (cont)

• The term "check" in reference to a message refers to the count of the number of words in the message.

• The recommended guideline for the maximum number of words to be included in the text of an emergency message is 25 words.

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Radio waves, propagation, and antennas T9A

• A vertical antenna is an antenna that consists of a single element mounted perpendicular to the Earth's surface.

• A horizontal antenna is a simple dipole mounted so the elements are parallel to the Earth's surface.

Antenna types – vertical, horizontal

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Concept of gain• The advantage of 5/8 wavelength over 1/4

wavelength vertical antennas is their radiation pattern concentrates energy at lower angles.

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Concept of gain (cont) • A beam antenna is an antenna that

concentrates signals in one direction.

• The quad, Yagi, and dish are all types of directional or beam antennas.

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Common portable and mobile antennas, losses with short antennas• A disadvantage of the "rubber duck" antenna

supplied with most hand held radio transceivers is it does not transmit or receive as effectively as a full sized antenna.

• A good reason not to use a "rubber duck" antenna inside your car is that signals can be 10 to 20 times weaker than when you are outside of the vehicle.

• A magnet mount vertical antenna is one type of antenna that offers good efficiency when operating mobile and can be easily installed or removed.

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Relationships between antenna length and frequency

• The physical size of half-wave dipole antenna becomes shorter as the operating frequency increases.

• The approximate length, in inches, of a quarter-wavelength vertical antenna for 146 MHz is 19 inches. [Remember the relationship between wavelength and frequency.]

• The approximate length, in inches, of a 6-meter half- wavelength wire dipole antenna is 112 inches. [Remember the relationship between wavelength and frequency.]

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The ¼ & ½ Wave Vertical

Length of vertical in feet =

234 f (MHz)

¼ Wave 19”

¼ Wave Radials

Feed Point

½ Wave 112”Feed Point

½ Wave Radials

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Dummy loads• The primary purpose of a

dummy load is it does not radiate interfering signals when making tests.

[Actually, it may radiate but the signal level radiated is usually well attenuated.]

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Radio waves, propagation, and antennas T9B

Propagation

• VHF/UHF signals not normally heard over long distances due to VHF and UHF signals usually not being reflected by the ionosphere.

• When we hear a VHF signal from long distances a possible cause is sporadic E reflection from a layer in the ionosphere.

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Ionospheric Layers

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Critical Angle

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Fading, Multipath distortion

• Picket fencing is a term commonly used to describe the rapid fluttering sound sometimes heard from mobile stations that are moving while transmitting.

• If a station reports that your signals were strong just a moment ago, but now they are weak or distorted, try moving a few feet, random reflections may be causing multi-path distortion.

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Fading, Multipath distortion (cont)

• The most likely cause of sudden bursts of tones or fragments of different conversations that interfere with VHF or UHF signals is when strong signals are overloading the receiver and causing undesired signals to be heard.

Reflections• A way to reach a distant repeater if buildings or

obstructions are blocking the direct line of sight path is to try using a directional antenna to find a path that reflects signals to the repeater.

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Radio horizon, Terrain blocking

• The radio horizon is the point where radio signals between two points are blocked by the curvature of the Earth.

• VHF and UHF Radio signals usually travel about a third farther than the visual line of sight distance between 2 stations because the Earth seems less curved to radio waves than to light.

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Radio horizon distance

• The distance, D1 to the radio horizon for the transmitter is 1.415 times the square root of h1 (feet).

• The theoretical maximum line-of-sight distance between two

elevated points, presumably the transmitter (h1) and the receiver (h2), is the sum of the two distances to the radio horizon (D1 + D2).

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Wavelength vs. penetration

• UHF signals often work better inside of buildings than VHF signals since the shorter wavelength of UHF signals allows them to more easily penetrate urban areas and buildings.

• [This means 440 mHz (70 centimeters) signals, being UHF have a better chance of penetration inside buildings than 144 mHz ( 2-meters) signals do.]

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Antenna orientation

• If the antennas at opposite ends of a VHF or UHF line of sight radio link are not using the same polarization signals could be as much as 100 times weaker.

• A good thing to remember when using your hand-held VHF or UHF radio to reach a distant repeater is to keep the antenna as close to vertical as you can.

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Radio waves, propagation, and antennas T9C

Feedline types, Losses vs. frequency, matching and power transfer• Coaxial cable is used more often than any other feed

line for amateur radio antenna systems because it is easy to use and requires few special installation considerations.

• The characteristic impedance of the most commonly used coaxial cable in typical amateur radio installations is 50 Ohms.

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Coax Cable Signal Loss (Attenuation) in dB per 100ft

Loss RG-174 RG-58 RG-8X RG-213 RG-6 RG-11 9913 LMR-400

1MHz 1.9dB 0.4dB 0.5dB 0.2dB 0.2dB 0.2dB 0.2dB 0.3dB








1GHz 32.0dB 21.5dB 13.5dB 8.3dB 6.1dB 5.6dB 4.5dB 4.1dB

Imped 50ohm 50ohm 50ohm 50ohm 75ohm 75ohm 50ohm 50ohm

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SWR concepts

• In general terms, standing wave ratio (SWR) is a measure of how well a load is matched to a transmitter.

• It is important to have a low SWR in an antenna system that uses coaxial cable feedline to allow the efficient transfer of power and reduce losses.

• A reading on a SWR meter of 1 to 1 (1:1) indicates a perfect impedance match between the antenna and the feed line.

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Measuring SWR• A Directional wattmeter could be used to determine if

your feedline and antenna are properly matched.

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SWR concepts (cont)

• A loose connection in your antenna or feedline might be indicated by erratic changes in SWR readings.

• The SWR value, 2 to 1 (2:1) is where the protection circuits in most solid-state transmitters begin to reduce transmitter power.

• The power lost in a feed line is converted into heat by losses in the line.

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The Antenna TunerThe Antenna Tuner

““Antenna Tuners” do not really tune antennas.Antenna Tuners” do not really tune antennas.They provide an impedance match betweenThey provide an impedance match between

the transmitter and antenna system.the transmitter and antenna system.

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Weather protection• Losses can increase dramatically in older

coaxial cables that are exposed to weather and sunlight for several years.

• The outer sheath of most coaxial cables is black in color because black provides protection against ultraviolet damage.

Feedline failure modes• Moisture contamination is the most common

reason for failure of coaxial cables.

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Practice exams on the Internet

• HTTP://www.qrz.com/p/testing.pl

• HTTP://www.eham.net/exams/

• HTTP://www.aa9pw.com/radio