ARCSquared
Radio Group (www.arcsquared.org)
American Red
Cross Northern New Jersey Regional Chapter
Amateur
Radio Technician Study Sheet Instructions
The following pages contain information extracted from the question
pool. Information is on this sheet
because it simply requires memorization and addresses multiple questions in the
pool. To prepare for the class, read
through this information and memorize as much as possible in advance. There are practice tests available
online see links here. These practice
tests use the actual FCC question pool and provide a sample of the material
covered in a real test.
Technician Class
Frequency Privileges (1500 watt PEP max)
These are the frequencies allocated for us to Technician class
operators after passing the written (element 2) exam. There is an inverse proportional relationship
between frequency and wavelength. Longer
wavelengths have lower frequencies.
There are several frequency to wavelength conversion questions using the
formula shown.
Identification
All operators must identify themselves with their FCC callsign every 10
minutes while talking and at the end of a transmission or it is an illegal
“unidentified transmission”. There is no
requirement to ID at the beginning – it only helps the other operator. CW (morse code) at less than 20 words per
minute is always an acceptable way to ID.
License Period
An amateur license is valid for 10 years. It can be renewed no earlier than 90 days in
advance. There is a two year renewal
grace period during which time the license is not valid but can be renewed with
no loss of privileges (no retest).
Transmitting during the grace period is not allowed.
Good Amateur Practices
The radio spectrum is a shared resource and the FCC rules are largely
based on “play nicely with others”. Good
Amateur Practice is exactly that. They
include “listen before transmitting” to insure the frequency isn’t already
being used. If you want to break into a
conversation in progress, you simply give your callsign between exchanges, the
word “break” is only used to indicate emergency traffic. Additionally, Amateur Radio also cannot
compete with commercial services so there is no broadcasting, business or music
allowed (music can only be transmitted as incidental to a Space Shuttle/ISS
rebroadcast).
Repeater Frequency
Separation (
Repeaters are often placed on hilltops to extend the range of mobile
and portable stations (handhelds). They
listen on one frequency and simultaneously retransmit on another. The difference between transmit and receive
frequencies is called “split” and varies for each band. All new radios know the split for each band
but older units may not.
Bandwidth
Bandwidth determines how much spectrum a signal occupies. Narrower signals tend to be more efficient
and have longer range.
Ohm's
Law and Power Formulas
The circles are designed as a memory tool to help you remember the
formulas. The first circle is Ohm’s
law. To use them, simply cover the value
you want and solve remaining equation.
To solve for E (voltage or Electromotive force), cover it up and
multiply current in amperes times resistance in ohms. To solve for resistance, cover R and divide
voltage in volts by current in amperes.
All the formulas are listed below.
Blank paper is provided for the test and participants are allowed to
write down whatever they need.
Batteries
There are a number of common battery types currently available. The old Carbon-Zinc batteries have been
largely replaced by Alkaline. Alkaline
batteries have great life but both are non-rechargeable and run about 1.5 volts
per cell. Rechargeable batteries evolved
from Nickel Cadmium (NiCd) to Nickel Metal Hydride (NiMH) to Lithium Ion
(LiIon). NiCd and NiMH both share the
same 1.2 volts per cell but don’t have nearly the battery life as LiIon
batteries.
Unit Conversions
These are basic metric conversions.
Notice they involve moving the decimal place some number of digits right
or left. 1,000 Kilohertz = 1 Megahertz.
Frequencies
Radios and telephones are both designed to carry Voice Frequencies
between 300-3000 Hertz. Radio Waves
generally begin at a range above human hearing at 20,000 Hertz
Measuring Units
These are the basic units of measurement of these values. These are often expressed as large or small
units. Amperes are large and are often
found as MilliAmpere or MicroAmpere.
Ohms are small, so KiloOhms or MegaOhms are common.
Radio Functions
This section refers to actual knobs and buttons on an amateur radio
(and many others). Up/Down buttons on
the radio or microphone allow tuning different frequencies or memory channels. Shift allows changing the transmit and
receive frequencies for working through repeaters. The Noise Blanker is designed to quiet
ignition (pulse-type) noise. The
Function or (F) key allows accessing secondary functions on many radios. Tuning is accomplished via the tuning knob
known as VFO (Variable Frequency Oscillator) knob, Up/Down buttons or a keypad
on the radio. The Step or Tune Step (TS)
button allows quick or fine tuning by adjusting the tuning increment. Receiver Incremental Tune (RIT) allows
fine-tuning of the receiver without affecting the transmit frequency. The Squelch function is designed to keep the
radio quiet when there is no signal present.
Radio Modes
The simplest radio signal is just a single frequency. By turning that radio wave on and off, it’s
possible to send morse code (CW).
Amplitude Modulation is the simplest voice modulation scheme but it’s
not very efficient because it has two identical (redundant) sidebands with the
voice information and the radio carrier that doesn’t contain any
information. Amateur radios often use
Single Sideband (SSB) transmissions that are spectrally (space) and power
efficient by removing one of the AM sidebands and the carrier before
transmission. This leaves either the
upper or lower sideband (USB/LSB).
Convention dictates that lower sideband (LSB) signals are used below
10MHz and upper sideband (USB) is used above 10MHz.
Q Signals
Q Signals are shorthand created for morse code operators. Many of these have found their way into voice
operations as well. The bolded items are
asked specifically.
SWR
SWR stands for Standing Wave Ratio and is a measure of how well the
antenna is matched to the radio. A 1:1
SWR means all the radio output power is being transferred to the antenna and is
ideal. A high SWR can overheat the radio
so most radios have circuitry that lowers output levels as SWR increases.
Antenna Lengths
The dipole is the basic “T” shaped antenna, similar to what is supplied
with FM stereos that tack to the wall.
The top of the antenna is a half wavelength for the desired frequency
and the feed line (coax) can be any length.
The formula for calculating the top length is shown. There are a number of vertical antenna
designs but the ¼ wave is the basic design.
Notice the formula for this provides a number exactly half the length of
the dipole.
There is also mention of yagis, quads and dish antennas. All of these designs are very
directional. Yagis have multiple
elements like TV antennas. Quads are big
loops and can also be made into multi-element antennas. These multi-element designs are generally
referred to as “beams”.
RF Safety
Surprisingly low voltages and currents can cause injury or death in the
proper combination. The FCC is also concerned
about human exposure to RF fields. The
FCC has defined maximum transmitted power levels allowed before a station
evaluation is required. The station
evaluation is used to identify RF exposure to humans nearby.
Technician Class
Frequency Privileges (1500 watt PEP max)
6 meters 50-54 MHz
2 meters 144-148 MHz
1.25 meters 222-225
MHz - (219-220 MHz point-to-point digital links)
70 centimeters 420-450 MHz - (435-438 MHz satellite
subband)
23 centimeters 1240-1300 MHz
Bands
are organized with narrow modes
(CW) near the bottom.
Valid
US callsigns
start with A, K, N or W (WANK) and contain 1 digit (0-9).
The
Federal Communications Commission (FCC) regulates radio use in the
License
Period
– 10 years with 2 year grace and can renew 90 days before expiration.
A
Club must have at least 4 members to be eligible for club license.
Identification - Must ID every 10
minutes and at the end of transmission – CW <20WPM OK
Good
Amateur Practices
Listen
before transmitting.
Just
transmit callsign to break into a conversation.
Amateur
Radio allows no broadcasting, no music transmissions, no codes/ciphers intended
to obscure a message, no swearing, no ethnic/racial slurs and no business.
Filters
Spurious
emissions/harmonics (your problem) require low-pass filter at transmitter.
RF/frontend/fundamental
overload (their problem) requires high-pass filter at TV receiver.
|
Repeater
Frequency Separation ( 2 meter band 600 kHz 70 centimeter band 5.0 MHz |
Bandwidth PSK31 signal 31 Hz SSB
signal 2-3 kHz
FM signal 5-15
kHz TV (NTSC) signal 6 MHz |
|
Ohm's Law and Power Formulas
E =
Voltage in Volts
I =
Current in Amperes
R =
Resistance in Ohms
P =
Power in
Cover the value you need and divide or
multiply the remaining values as appropriate.
Examples:
E = I x R I
= E / R R
= E / I
P = I x E I
= P / E E
= P / I
Batteries
Lithium Ion (LiIon) batteries offer the best
battery life.
Nickel Cadmium (NiCd) “nominal voltage” is
1.2 volts per cell.
Unit
Conversions
|
Mega |
106 |
1,000,000 |
|
Micro |
10-6 |
0.000001 |
|
Kilo |
103 |
1,000 |
|
Milli |
10-3 |
0.001 |
Voice Frequencies
are 300-3000Hz and Radio Waves are >20,000Hz.
Measuring Units
|
Frequency |
Hertz |
|
Resistance |
Ohm |
|
Current |
Ampere |
|
Power |
Watt |
|
Electromotive Force |
Volts |
|
|
|
Radio Functions
|
Up/Down
change frequency/memory |
Tune via keypad or VFO |
|
Shift
changes receive/transmit offset |
Step
(TS) adjusts tune rate |
|
Noise
Blanker (NB) quiets ignition noise |
RIT
– Receiver Incremental Tune |
|
Function
(F) key accesses alternate key
actions/functions |
Squelch
quiets receiver |
Radio Modes
Amplitude Modulation (AM), Single Sideband
(SSB) and Code (CW) are all related.
Upper Sideband (USB) is used on VHF
frequencies and above.
AMSAT is responsible for
most amateur radio satellites.
Q Signals
|
QRM |
Man-made noise |
QRN |
Atmospheric noise |
|
QSY |
Change frequency |
QTH |
Current/home location |
|
QSB |
Atmospheric fading |
QSL |
Confirmation of report |
CQ
means calling any station. Respond with station callsign (this is) your callsign.
Emergency Communications
RACES serves government agencies and ARES
serves non-government groups.
Messages contain name of sender in the
preamble, no more than 25 words and a check.
SWR of 1:1 is perfect
and near 2:1 transmitters generally start reducing power output.
Antenna Lengths
Half
Wave Dipole L = 5600 Where: L
= Length in Inches
F
(MHz) F = Frequency in
MHz
Quarter Wave
Vertical L = 2800
F
(MHz)
RF Safety
Voltage as low as 30V can be dangerous and
current as low as 100mA can be deadly.
Greater than 50 watts PEP at the antenna on VHF and up requires a station evaluation.