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  #1  
Old 01-18-2008, 01:21 PM
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Default Ham Radio Lic Notes

Cut, Paste, Slash, Burn, Print or Whatever and bring them to class !!!!!!!!!!!!

Notes for the T1 section - FCC Rules & Station License Responsibilities


Amateur operator - person who has an amateur license in the FCC database

- hams can transmit from anywhere the FCC governs radio

- hams cannot talk to hams using other services (like CB) on their ham radios unless authorized by the FCC

- anyone can become a ham except a representative of a foreign government

- no minimum age

- once you pass your test, you can transmit as soon as your call sign appears in the FCC database

- ham licenses are good for 10 years (and are renewable); there is a 2 year grace period to get it again if it expires

- your responsibility as a ham is to operate your station within the FCC rules

- you are required to give your current mailing address to the FCC; they can revoke your license if you don't

Amateur station - a station in the amateur service

Basic purposes of amateur radio

1. To serve as a voluntary noncommercial communications service

2. To contribute to the art of radio

3. To encourage increasing skill in communications and technology

4. To expand the reserve of trained operators and electronics experts

5. To enhance international goodwill

Volunteer Examiner - volunteer amateur who administers ham tests, accredited by a VEC (Volunteer Exam Coordinator)

- three examiners of General class or higher needed to give tests

CSCE (Certificate of the Successful Completion of an Exam)

- paper that says you passed a ham radio test

- if you pass one test you get a CSCE good for a year

FCC (Federal Communications Commission)

- makes and enforces the rules

Harmful interference - a transmission that disturbs other communications

ITU (International Telecommunications Union)

- international body that makes worldwide rules for radio

- the world is divided into 3 ITU regions

Region 1: Europe, Africa, Russia

Region 2: North & South America

Region 3: Australia, Asia (other than Russia), Pacific

Call signs - used to identify your station

- given out by the FCC in sequential order (K3AAA, K3AAB, etc.)

- clubs can have their own call sign; apply through a Club Call Sign Administrator

- special 1x1 call signs (W3A, K2B, etc) used for special event stations can be obtained temporarily by any ham

- all USA call signs begin with A, K, N, or W, and have a single digit number

Last edited by Seldom Seen; 11-24-2010 at 08:41 AM.
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Old 01-18-2008, 01:23 PM
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Notes on the T2 section - Control Operator Duties


You are not permitted to…

…transmit information to the general public (no "broadcasting")

…transmit music (unless you're rebroadcasting space shuttle communications and they have music on in the

background)

…use codes or ciphers

…transmit false or deceptive signals (no fake distress calls)

…transmit without identifying your station (by giving your call sign)

…transmit indecent or obscene language

…transmit for money (there are special exceptions in the Part 97 FCC rules)

…conduct business

…buy and sell equipment on a regular basis (occasionally is okay)

Identifying your station

- your call sign is used

- you must ID every 10 minutes and at the end of a contact

- repeaters can ID with Morse code or phone (voice) or video images

- you must ID in English

- during a special event station, when using a special call sign, you must ID with your own call sign once per hour

- special indicators are used at the end of call signs:

/m = mobile /p = portable

/KT = new Tech license on the way

/AG = new General license on the way

If you are at another ham's station:

- you are both responsible for the station's transmissions

- if you have a different class of license than him, you can use any band your license allows

- if you have a higher license and you're on a band he can't use, you must ID using both your call signs (his first,

then yours)

Control operator

- person controlling and responsible for a station's transmission

- there must be a control operator anytime you're transmitting

- to operate a repeater, you must have at least a Tech license

Control point - the location where the control operator function is performed

- local control: control operator is at the control point

- remote control: control operator controls radio through a telephone or radio link

- automatic control: using a device that control a radio (such as a repeater)

- if you have an automatically controlled station, the control operator does not have to be at the control point

Miscellaneous rules

Club stations - must have at least 4 members to get a club license

You can operate on an airplane, but you must have the pilot's permission and not use the aircraft's radio equipment

A person can only have one ham license

FCC can inspect your station upon request

Third-party communications - sending a message from one ham to another for someone else (or letting a non-ham talk on

the air under your supervision)

To prevent unauthorized use of your station, disconnect your power and microphone cables when not using your radio.
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Old 01-18-2008, 01:25 PM
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Notes on the T3 section - Operating practices


When getting on the air, listen first to see if the frequency you're on is being used

No one "owns" a particular frequency; all hams share them

CQ, followed by your call sign, is used to look for a contact (CQ = calling any station)

When answering a CQ, send the other's station's call sign, then yours (be sure you are on a frequency you're allowed to

use first)

To interrupt an on-the-air conversation, say your call sign between transmissions

Always use the minimum power needed to communicate

On a repeater, procedures are a bit different:

- to interrupt a conversation (a QSO), say the other person's call sign, then yours

- instead of calling CQ, you just say your call sign to look for someone to talk to

- when using a repeater, listen before transmitting; ID legally; use minimal power

Test transmissions - to make sure you radio is working ok

- you must still ID

Phonetic Alphabet - used to spell out words

- standard phonetics are used; avoid making up your own or using "cute" ones to avoid confusing

other hams, especially foreign hams

-standard phonetic alphabet:

Alpha ... Golf ... Mike ... Sierra ... Yankee ...

Bravo ... Hotel ... November ... Tango ... Zulu ...

Charlie ... India ... Oscar ... Uniform ...

Delta ... Juliet ... Papa ... Victor ...

Echo ... Kilo ... Quebec ... Whiskey ...

Foxtrot ... Lima ... Romeo ... X-ray ...

Band plan - a voluntary guideline to use certain operating modes in certain parts of bands

- developed by hams and ham organizations

- among the bands used by Techs, there are mode-restricted sub-bands on the 6 meter, 2 meter, and 1.25 meter bands

on 6 m: 50.0 - 50.1 is for CW (Morse code) only

on 2 m: 144.0 - 144.1 is for CW only

Repeater coordination - repeaters operate on certain frequencies; they are assigned these frequencies by repeater

coordinators to make sure they don't interfere with one another and to use the available space on the radio bands

(available "spectrum") efficiently

- repeater frequency coordinator: person in charge of repeater frequency band plan

If a repeater is used to send an illegal transmission, the person sending the transmission is responsible (not the person or

club that owns the repeater)

Indecent and obscene language is prohibited…

…since it offends some people

…since young children might be listening

…since it violates FCC rules; there is no official list, use discretion

Racial & ethnic slurs offend people and reflect poorly on all hams; don't use them.

Political discussions, jokes and stories, religious discussions okay, but be careful not to offend when discussing sensitive

topics. Always operate using good engineering and amateur practices.

If you hear a new ham having trouble on the air, offer to help

If you are told you are causing interference, check your transmitter to make sure it is working properly (not emitting

spurious signals or transmitting off-frequency)

Front end overload - when a strong nearby signal overloads a nearby TV or radio (when your neighbor hears your

radio signal through his TV or radio)

- if your radio is working okay, the owner of the TV is responsible

- a lot of modern electronics equipment (telephones, TVs, etc) is not built with adequate

interference protection

If you interfere with another ham on the air, ID your station and move to another frequency

Sometimes if TV cable is broken, it can make the TV pick up interference or cause interference to your ham radio

Use a dummy load to test your radio without actually sending out a signal ( a dummy load is a device that takes the radio

waves you're transmitting and changes them to heat)

RACES - Radio Amateur Civil Emergency Service

ARES - Amateur Radio Emergency Service

RACES and ARES are organizations that assist in emergencies


More to Follow
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  #4  
Old 01-18-2008, 03:54 PM
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Notes on the T4 section - Radio and Electronic Fundamentals


Units of electrical quantities

current - measured in amperes (A)

power - measured in watts (W)

voltage - measured in volts (V)

resistance - measured in ohms (Ω)

frequency - measured in Hertz (Hz)

wavelength - measured in meters (m)

Metric prefixes

mega- (M) 1,000,000

kilo- (k) 1,000

milli- (m) 1/1,000

micro- (μ) 1/1,000,000

Current

- the flow of electrons in a circuit

- direct current (DC): flows in one direction only

- alternating current (AC): flows back and forth in alternating directions

- conductors (metals, acids, bases) allow charge to flow easily through them

- insulators (wood, glass, plastic) do not allow charges to flow easily

- measured using an ammeter

Resistance

- electrical friction due to electrons' collisions with atoms inside the conductor

Voltage

- electrical pressure that pushes the electrons through a circuit

- auto batteries provide 12 volts

- measured using a voltmeter

-also called EMF (electromotive force) or electrical potential difference

Frequency

- the number of times per second that an AC current switches direction, or, the number of complete radio waves

produced by a radio per second

- voice frequencies: sounds from 30-3000 Hz

- audio frequencies: frequencies from 20-20,000 Hz

- radio frequencies: frequencies above 20,000 Hz

- 6 meter band: frequencies from 50-54 MHz

- 2 meter band: frequencies from 144-148 MHz

- 70 cm band: frequencies from 420-450 MHz

Wavelength

- length of one complete radio wave

- often "bands" are referred to by their wavelengths

Relationship between frequency, wavelength, and the speed of a wave:

- speed = frequency × wavelength

-equation: c = f × λ

c = speed

f = frequency

λ = wavelength

- radio waves move at the speed of light: c = 300,000,00 m/s or 3 x 10 (to the 8th) m/s

- as the frequency of a radio wave increases, its wavelength decreases (and vice-versa)

Electrical devices

- receiver: converts radio waves to sound waves

- transmitter: converts sound waves to radio waves

- transceiver: combined receiver and transmitter

- power supply: converts AC from wall outlet to DC for radio

- amplifier: increase power put out by radio

- battery: provides DC voltage

- single battery is called a "cell"

- lithium-ion batteries have the longest lives

- nickel-cadmium batteries provide 1.2 volts each

- carbon-zinc batteries: non-rechargable

- to keep rechargeable batteries stored for emergencies…

…check them periodically

…recharge every 6 months

…keep cool and dry

- draw current from a battery slowly to help it last longer

Ohm's law: the relationship between current, voltage, and resistance

- equation: E = I x R

E = voltage

I = current

R = resistance

Power equation relating power, voltage, and current

- equation: P = E x I

P = power

E = voltage

I = current

Last edited by Seldom Seen; 01-26-2008 at 03:24 AM.
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Old 01-20-2008, 04:23 PM
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Default T5

Notes on the T5 section - Station Setup and Operation


Station equipment

Microphone - connected to the transmitter

- converts sound to electrical signals (an audio signal)

Speaker - converts electrical signals to sound

- if the speaker is too close to the microphone, feedback can result

- if it's too noisy for speakers, use headphones

Regulated power supply - supplies electrical power without equipment-damaging voltage fluctuations

Filter - used to block "spurious emissions," signals your radio should not be putting out on top of the desired signals

- connected to the transmitter output

- high-pass filter: lets higher frequencies through, blocks lower ones

- low-pass filter: lets lower frequencies through, blocks higher ones

- band-pass filter: blocks signals above and below a certain frequency

- notch filter: blocks signals of a certain frequency, lets all others through

- if your 2 meter band signal is coming through your neighbor's TV ("receiver overload"), use a notch filter

Terminal Node Contoller (TNC) - connects the radio to a computer of you are using packet radio

- no microphone needed for packet; your radio sends computer data, not your voice

- some computers' sound cards can also be used to connect a computer to the radio

Operating controls

Microphone gain - the "volume" of the voice signal you're sending out

- if the microphone gain is set too high, it can distort your signal

Memory - a lot of radios have memories (like a computer)

- memory can be used to save operating frequencies, CTCSS tones, power levels, etc.

Variable frequency oscillator (VFO) - controls what frequency the radio is on

- usually a knob you turn on the radio

- on some radios, you can also use a keypad to enter the frequency

Squelch - used to quiet noise when no signal is being received

Noise blanker - blocks electrical noise, like static produced by your car when you start it

Up/Down microphone buttons - used to change frequency easily

Shift control - used to adjust the offset between the transmitting and receiving frequencies

Receiver Incremental Tuning (RIT) - used to change what frequency you're listening to without changing the

frequency you're transmitting on

Step button – used to change how much the frequency changes when you tune

Function button – used when one button has to do more than one thing (like the 2nd button on calculators)

Repeaters

- used to extend the range of mobile or other low-power stations

- a courtesy tone is a beep the repeater makes after each transmission

- you must know the repeater’s input and output frequencies to use it

- usually, on the 2 meter band, the input and outputs are 0.6 MHz apart in frequency (the “offset”)

- pause between transmissions in case someone wants to break in

- on the 70 cm band, the offset is usually 5 MHz

- simplex: not using a repeater, just receiving and transmitting on the same frequency

- use simplex if possible to avoid tying up the repeater

- to see if you can use simplex, check to see if you can hear the other station on a repeater’s input

- linked repeaters can be used to send signals over longer distances

- to avoid interference, check with your local repeater coordinator before putting a new repeater on the air

- not all repeaters are open; some have owners who restrict access to certain users (“closed”)

Radio Problems

- three basic types: fundamental overload, spurious emissions, and harmonics

- fundamental overload: interference from a strong, close radio

- spurious emissions: putting out undesired radio signals with the regular signal

- harmonics: putting out undesired signals on a multiple of your frequency

- telephones are usually not equipped with interference protection, and its acts like a radio sometimes; install an RF

filter at the telephone

- if someone complains about TV interference: check to make sure your radio is okay; see if your own TV is

affected; chokes or filters may be needed

- if your neighbor’s Part 15 device causes interference with your radio, work with your neighbor on the problem;

politely tell him the problem and tell him the rules require he stop using the device; check your station to see if it

working okay

- whine on your mobile radio signal? Check for noise from the car’s electrical system (“alternator whine”)

- SSB garbled and breaking up? Feedback in the microphone

- signal through repeater distorted or weak? Transmitter off frequency, or low batteries, or bad location

- digital communications systems can often eliminate noise or interference


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Old 01-20-2008, 08:31 PM
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Notes on the T6 section - Communication Modes and Methods


Phone – voice transmissions by radio

- includes AM, SSB, and FM

Modulation – a way of altering a radio wave so that it can carry information

- involves mixing a radio wave (the “carrier”) with a voice or other signal

Amplitude Modulation (AM) – modulation method where the carrier’s “height” changes when it’s mixed with your voice

Single sideband – when an AM signal is created, there are three parts: the carrier, the upper sideband (USB) and lower

sideband (LSB)

- voices sent using AM sound very natural but are very wide on the band

- by removing one of the sidebands, we can make the signal narrower (about 2 to 3 kHz wide)

- used for worldwide communications on HF

- used for long-distance and weak signal contacts on VHF and UHF

- LSB is used below 14 MHZ

- USB is used on 14 MHz and above, including VHF and UHF

Gateway – ham radio connected to the internet

FM – frequency modulation

- used with repeaters on two meters a lot; very clear and natural sounding

- very large bandwidth (about 5 to 15 kHz wide)

CW – Morse code signals

- narrowest bandwidth of all

- only send at speeds at which you can comfortably receive

- repeaters often use CW to identify

Fast-scan TV – extremely wide bandwidth (about 6 MHz)

- often used on 70 cm since it is a wide band

Echolink – uses the internet to send voice transmissions (Voice over internet protocol, VoIP)

- any ham can use this

- it is possible to hear DX on 2 meter repeaters this way

- active nodes using VoIP can be found in a repeater directory or on the internet

IRLP – internet radio linking project; also uses VoIP

- use the keypad on the radio to send the ILRP node numbers to select a node

Packet radio- digital (computer-to-computer) communications

APRS – automatic position reporting system (for sending GPS info over ham radio)

-requires a GPS receiver

NTSC – national television system committee

- a standard fast-scan color TV signal

Technicians can use point-to-point digital message forwarding on 1.25 meters (219-220 MHz)

PSK – phase-shift keying

- modulation method involving varying the phase of a signal

PSK31 – low-speed PSK that works well in noisy conditions

Q-signals: abbreviations used on ham radio

QRM – Q-signal for “interference”

QSY – Q-signal for “changing frequency”
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Old 01-21-2008, 12:24 AM
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Default T7

Notes on the T7 section - Special Operations


Field operations

- bring extra battery packs for your handheld

- leave the 1500 watt amp at home (too heavy)

- use an external antenna instead of the "rubber-duck" antenna

- combination headsets/microphone helpful if there's background noise

Radio Direction Finding & Fox Hunting

- RDF used to find sources of interference or jammers, or in fox hunts

- fox hunting: contest in which hams try to find hidden transmitters

- directional antennas used for both of these

Contests - involves contacting as many stations as possible in a certain amount of time

Grid locator - letter/number combination used as a geographic location designator

Special Event Station - temporary station that operates in conjunction with an activity of special significance

Radio Control

- maximum power is 1 watt

- a label must be attached to the transmitter with call sign and address

Satellites

- any ham can use the ham radio satellites in orbit as long as you are allowed to use the uplink frequency

- use the minimum power needed

- can be used to talk to hams in other countries

- any ham can contact the ISS (International Space Station)

- beacon: radio signal giving information on the satellite

- a satellite tracking program is used to find when you can access a satellite

- Doppler shift: change in frequency caused by the satellite's motion

- AMSAT: biggest group that builds and launches ham satellites

- sub-band: portion of a band where satellite operations are permitted

- on the 70 cm band, the satellite sub-band is from 435-438 MHz

- a LEO satellite is in a low Earth orbit
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Old 01-21-2008, 12:26 AM
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Notes on the T8 section - Emergency and Public Service Communications


When the FCC declares a communications emergency, they will state what special conditions and rules are to be followed

during the emergency.

Usually emergencies are the only time hams can communicate with stations operating in other radio services; this requires

FCC authorization. Hams not helping with the emergency must avoid using the emergency frequencies.

If you hear someone call for help, immediately stop your conversation and take the emergency call. Assume it is for real

and act accordingly.

Tactical call signs such as "command post" or "weather center" are used in emergencies to make communications more

efficient and to help coordinate communications

If calling for help on voice, "mayday" is used; on CW, "SOS" is used. It is considered an emergency if human life or

property is threatened

False emergency calls are illegal; you could have your license revoked, be fined, or go to jail

Emergency communications always have top priority; the rules on what frequencies you can use, etc., can be disregarded in

a true emergency

Preparing for emergencies; check your emergency equipment twice per year, make sure you can use it in a power failure,

participate in emergency drills

RACES is restricted to serving local, state, and federal government emergency management agencies

- before you participate in RACES, you must register with the responsible civil defense organization

ARES supports non-goverment agencies like the Red Cross, Salvation Army, and National Weather Service

- before you can participate in ARES, you must have a ham radio license

Emergency power - car or truck batteries, bicycle generators, or portable solar panels

Avoid casual chatter when operating a station for public service to avoid interfering with important traffic

It is illegal to allow a reporter to use your ham radio to make a news report

Personal information concerning victims should not be transmitted during emergencies

If you are participating in an emergency net, once you check in, don't transmit until the net control station requests it

Net control stations must have strong clear signals

If someone breaks in with an emergency, the net control station should stop all net activity and handle the emergency

If there is a big emergency and there is no net control station, start the emergency net yourself and ask for check-ins

When passing emergency messages, you must include the name of the person originating the message

If sending sensitive emergency traffic, use a non-voice mode like CW or packet radio to prevent casual listeners from

overhearing

The preamble of a message contains the info needed to track the message; this includes the message number, type of

message, handling instructions, length-of-message information (the "check"), the call sign of the station where the message

started, and when and where the message originated

Usually such messages are kept to 25 words or less
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Old 01-21-2008, 12:33 AM
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Default T9

Notes on the T9 section - Radio Waves, Propagation, and Antennas


Feedline – wire connecting the antenna to the radio

- most common type is coaxial cable (“coax”)

Beam antenna – concentrates signals in one direction

-examples include: Yagi, Quad, Dish

Vertical antenna – single conductor ("element") perpendicular to Earth’s surface

- often car antennas are short vertical antennas, ¼ or 5/8 wavelengths long

- car antennas often have magnetic mounts for attaching to the roof

- 5/8 wavelength antennas have lower radiation angles than ¼

Horizontal antenna – element parallel to Earth’s surface

Dipole antenna – wire antenna one half-wavelength long, usually horizontal

- the higher the frequency, the shorter the length

- equation: length (feet) = 468 / frequency (MHz)

- the wire is cut in the center; the coax is connected to the antenna at the center

- one half of the antenna is connected to the center conductor of the coax

- the other half is connected to the shield (the braided wire surrounding)


Rubber duck antenna – short rubber-coated antenna usually found on handheld radios

- not as efficient as full size antennas; especially bad inside cars

Dummy load – an “antenna” that does not put out a radio signal

- converts the radio energy to heat instead

- used to test radios without radiating a signal

Propagation – the ability of a radio wave to travel over distances

- different types of radio waves (HF, VHF, UHF) propagate differently

- HF signals can be reflected by the ionosphere (they “skip”)

- VHF & UHF signals don’t skip, so they usually only work line-of-sight

- they actually go slightly further than line-of-sight due to atmospheric refraction

- radio horizon: where radio signals are blocked by the Earth’s curvature

- sometimes VHF signals reflect from ionized patches in the E layer of the ionosphere (“sporadic E”)

- UHF signals work better inside buildings since their shorter wavelength allows them to penetrate better

- VHF & UHF signals can be reflected off of buildings (to repeaters, for example) using directional antennas

Problems on VHF & UHF

- bursts of tones or fragments of conversation on VHF or UHF: receiver overload from strong nearby signals

- suddenly weak or distorted signal: try moving a few feet, perhaps multiple reflections causing destructive

interference

- when a repeater is distant, be sure to hold your handheld’s antenna vertical, since repeater antennas are vertically

polarized. If polarizations don’t match, your signal might be up to 100 times weaker when it arrives.

Antenna testing is done by measuring SWR: standing wave ratio

- ratio of high to low impedance in a feed line

- is a measure of how well the feedline is able to deliver energy to the antenna

- a 1:1 SWR is perfect; this means 100% of the energy is going to the antenna, none is reflected

-above 2:1, a lot of power is being reflected; most modern radios have circuits that begin reducing transmitter power when the SWR is above this

- a SWR meter or a directional wattmeter can measure SWR

Coax – easy to use and doesn’t have many special installation requirements

- important to have low SWR when using coax to reduce losses and transfer power to the antenna efficiently

- power lost in a coax line is converted to heat

- weather and sunlight can increase losses in coax over time

- coax fails most often because of moisture contamination

- black plastic-coated coax can reduce ultraviolet damage

- most common type of coax for hams is 50 ohm

Last edited by Seldom Seen; 01-21-2008 at 01:22 AM.
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Old 01-21-2008, 12:36 AM
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Default T0

Notes on the T0 section - Safety

Electrical safety

- lowest voltage that can cause a shock = 30 V

- lowest current through body likely to cause death = 100 mA (100 milliamperes)

Fuses and wiring

- in a three-way electrical plug, the green wire is connected to ground

- fuses are to interrupt power in case of overload

- never replace a fuse with one that has a greater power rating, or too much current may flow and cause a fire

- to prevent electrical shock, use 3-wire power cords for all equipment; connect all equipment to common ground;

use ground-fault circuit interrupters

- make sure everyone knows where the emergency disconnect switch is

Car batteries (12 V storage batteries)

- can be recharged by connecting to car’s battery and running engine

- contains dangerous acid; short circuits can cause fires; explosive gas can collect

- can overheat or explode if charged or discharged too quickly

Lightning

- when a storm is approaching, disconnect antenna cables and move them away from equipment; unplug all

equipment; stop using radio equipment & stay away from it

- lightning strikes can cause fires

Power supplies contain large capacitors that can shock you even if it is turned off and unplugged.

Outdoor antenna work safety

- when near a tower someone has climbed, wear a hard hat and safety glasses

- before climbing a tower, put on safety belt and safety glasses; arrange for a helper; inspect the tower; make sure no

storms are approaching

- when putting up antennas, make sure people can’t touch them

- when putting up antennas near airports, there are height regulations

- when putting up a tower (or antenna), avoid power lines; if the antenna falls, it should still be more than 10 feet

from the power lines

- tower guy lines are installed according to manufacturer’s instructions

- crank-up towers cannot be climbed unless it is fully lowered

- stainless steel parts are used outdoors to avoid corrosion

- for safety, 8 foot ground rods should be installed at each leg of a tower and bonded together

Radio Frequency (RF) exposure safety

- VHF and UHF signals are considered non-ionizing radiation

- radio waves can be hazardous if too much power is absorbed by the body

- above 30 MHz, more than 50 watts PEP means you need an RF exposure evaluation

- exposure to RF energy depends on the frequency and power of the radio signals, the distance to the antenna, and the

antenna’s radiation pattern

- frequency is important since the body absorbs some frequencies better than others

- you can be sure you comply with the exposure regulations by calculating it using FCC OET bulletin 65 or computer

modeling, or by measuring it using calibrated equipment.

- if you touch antenna while someone transmits, you can get an RF burn

- you can lower exposure by relocating your antennas, altering your antenna patterns, or by changing your station’s

power or frequency

- re-evaluate your exposure if you get new equipment

- exposure is measured in units of milliwatts per square centimeter

- the “duty cycle” of a transmitter affects RF exposure, since the duty cycle determines the time the transmitter is

operating
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