Radio Equipment
ARRL Book Chapter 3, section 3.1
Basic Radio Station
• Source of Power
– Implied a way of connecting it
• A Transciever (combination transmitter to send
and receiver to receive)
– Probably have a microphone to send voice
– May have other sending equipment such as a
computer or Morse code telegraph key
• An Antenna to radiate the signal
– Implied a connection from transceiver to the antenna
– Coax cable is the common choice
Talking on a Radio
• Sending radio codes information into radio waves on a specific
frequency
• Receiving radio on the same frequency reads the radio waves and
decodes the information
• Transmitting and Receiving on the Same Frequency is called
Simplex Operation (T5C08)
– Radios can only communicate if they are coding and decoding
information on a common frequency
• Radios select the frequency using a VFO knob or keypad on a
microphone (T5B03)
– Usually turning the largest knob on the radio makes the frequency
change up and down
– Most knobs have a distinct click feel when turned. The size of the jump
in frequency with each click is called the step (most radios the standard
step is 5000 hertz or 0.005 megahertz)
– Most radios have a menu option called step that lets you set the
size of the frequency change with each click (T5B10)
– RIT refers to this receiver incremental tuning (T5B09)
The Problem of the VFO Knob
(by the way VFO stands for Variable frequency oscillator – it allows the
radio to send and receive on different frequencies)
• The 2 meter amateur band is from 144 to 148
megahertz.
– If you go in steps of 5000 hertz at a time it would take 800 steps
to go from end to end (that gets pretty old if your changing
frequencies)
• Many radios have an up and down button on the
microphone. These button tune frequencies up or
down one step at a time or choose a “a computer
memory” (T5B07)
– Some radios have up and down buttons on the radio itself
instead of knobs
• Some radios have keypads on the microphone or radio
and you type in the frequency
– This can be a lot quicker than turning a knob round and round
– It’s a nice feature – but most radios don’t have it
• Chris Pixton’s favorite Icom V8000 does have the feature.
• I use Azden 5000 in my car that key pads on the radio.
Radio Memory Features
• One way to get quick access to a commonly used
frequency is to store it in a memory channel (T5B05)
– Most of us our pretty use to our phone and calculators have memory
space to store things
– Probably want your radio to have memories
• 1990s vintage radios may have about 10 to 20 memories
• New radios from last 5 years have 200 to 500 memories
– President Shane envisions having 4 sub-areas of the Stake –
Sikestone/Popular Bluff, Jackson/ Cape, Farmington area,
Carbondale/Steelville
• In Carbondale/Steelville we have coordinated so that we store the same
frequencies in the same memories – we have 22 memories
• If we say channel 1 we all go to memory 1 which is 144.37 megahertz or the
Ward primary frequency
• A Typical radio memory channel can store a transmit frequency,
a receive frequency, a CTCSS frequency, and a power output
level (T5B02)
The Problem of Noise
• Always stray radio signals or noise – lighting is a big
cause
– See fuzzy picture on a TV or hear static
– Get the same static on a radio
• You can use that noise to help you set the volume on
your radio but probably don’t want to hear it all the time.
• Most radios have a squelch knob that block out
sounds when you are not receiving a message (T5B04)
– Trick is that most noise signal are weak – a squelch just blocks
all signals that are weaker than a certain amount
– Warning – setting squelch too high can block weak messages to
• I was having trouble getting a message from Farmington – my wife
had turned up the squelch
– After you set the volume you usually turn the squelch up just
enough to make the noise disappear
Repeaters
• Repeaters increase your range. They are
usually on very high ground – they take your
signal and repeat it
– We have a big Stake when we try to do a net across
the whole stake we use repeaters (usually Alto Pass
146.85 megahertz)
• A repeater would talk over itself if it tried to
receive and resend on the same frequency
– Repeaters receive signals on one frequency and
send them on another frequency (T5C07)
– We often call talking on a repeater “Duplex” (because
it has a separate send and receive frequency)
Duplex
• Most important information to know before
using a repeater is the input and output
frequencies (T5C03)
• Can be interesting because when you squeeze
the push to transmit button on the microphone
you will see the frequency display change
• Spacing between send and receive frequencies
is called an “offset”
– There are standard spacings
– The Most Common 2 meter repeater offset is 0.6
megahertz (600 kilohertz) (T5C05)
– The Most Common 70 centimeter repeater offset
is 5 megahertz (T5C06)
More on Repeaters
• Range of VHF signals varies with weather
– Sometimes more one repeater on a frequency
• Alto Pass, Suburban St. Louis, and Peoria all on same frequency
• Repeaters use CTCSS tones to tell which repeater was intended
– This is a sub audible tone than has to be sent with the signal to tell a
repeater the message if for it
– Many 1980s vintage radios do not have CTCSS tones, can’t use them
on many repeaters (may be a back-up radio, but probably not primary
in this area where we do use repeaters some)
– We try to use simplex because never know when a repeater will be
down
• Auto offset – Since repeaters function in certain
frequency ranges some newer radios recognize repeater
frequency and put in offset automatically
– Older ones have to separately set transmit and receive
frequency
– Can be easier if a repeater has a non-standard offset, but
nothing around here does.
Simple and Fancy
• Older radios have buttons and dials that perform
basic radio functions
– Turn on the CTCSS tone by pushing the Tone button
• Newer radios have numerous special features –
they are made to be small so can’t put buttons
all over them
– They use menus activated by pushing the right series
of buttons
– Most radios have an F button that is used to pick
multiple functions for one button (T5B11)
Which is Best?
• If buying a newer radio you already know it will be fancy
– Used radio – who knows could be old or a bargain new.
• Most radios will have features don’t use every day
(memories make setting offsets, CTCSS and frequency
unnecessary)
– Hard to remember everything
• Suggestions on remembering
– Make a copy of your instructions (on paper to store with your
radio and stash the original)
– I have a condensed instruction sheet for basic functions that I
created
– Consider buying the same radio as a friend so that you can
compare notes
• Chris Pixton likes the Icom V8000
Message Security
• Church has emphasized keeping things simple
– This has favored voice on common VHF radios
• Down-side, privacy, scanners routinely listen to amateur
radio.
– Can be great getting help but if you identify the location of a
problem it can be directions for looters
• Church suggestions
– Consider whether sensitive person information needs to be
transmitted on non-secure systems
– Standard maps, (the M family at E4 on page 51)
• Its not code – E4 is a map coordinate and page 51 is the 51rst page
in a map book
• But not everyone has the map book
– Details and procedures may come down to a local plan.
List Handling
• In addition to security, one limit of voice it the list.
– Describing a map or image can be almost impossible
– With list one word may sound like another or you can
forget something
• People are trying to read a list on one side and recreate it on
another
• One solution is digital handling
– Can send e-mails, images, and lists digitally
– Digital transmissions require decoding – not
everybody with a radio shack scanner can do that
Digital Modes
• Computer talks into the radio instead of your voice
– A microphone is not needed for packet radio (T5A09)
– For Packet Radio to connect between a computer and a
radio you need a terminal node controller (T5A08)
•
Some newer radios are already packet ready and have node controllers built in
– A computer can make data ready to send over a radio with a
sound card (T5A10)
– A radio can also be linked to an internet line – such a radio
station is called a gateway (T6A03)
• There are already networks of computers that are part of gateway
systems
• Privately maintained just like repeaters
• Can be used for voice – I talked to a guy in Arizona on 2 meters,
Lee talked to a guy from England
What Does the Church Do With
Digital
• The Church has considered adopting digital guidelines
– Right now much more emphasis on people getting emergency
plans and capabilities
• A back-up communication system cannot depend on the
system it is intended to replace
– If phones are out many internet lines will be out too
• Of course if you can radio to a gateway out of the damage area you
may be able to use internet lines
• Packet does not depend on gateways to enable computer
communication
– “Paulism” concern – power for a computer is much worse than a
radio
• Laptop battery only good for about 2 hours
• Back-up generators (except premium Honda’s) often do not give
clean electric power sine waves – computers are much more
sensitive to “dirty power” than battery chargers (where do you
charge your laptop battery?)
Trouble Shooting Ideas
•
Feedback – If your microphone is located too close to the speaker you
will get audio feedback (T5A03)
– Most of us have already had the unpleasant experience of getting our ears blown
out with a feedback squeal in a sound system in an auditorium
– Radio Frequency energy gets into microphone circuit it can cause Single
Side Band (SSB) signals to be garbled and break-up (T5D11)
•
Another Garbler
– What happens if you try to play music too loud for the speakers and amplifier
circuits on your stereo
– In radio the microphone signal goes through a pre-amplifier before going to the
final amplifier on the radio
• The setting of pre-amp is called the gain on the microphone
• Some radios may seem to send real soft signals – have the gain on the mike checked –
it may be too low
• If the gain on the microphone is set too high the signal will become distorted and
unreadable (T5B01)
•
When you hold the microphone hold it to the side of your mouth and talk
across it
– This will prevent breathy pops from hyperventilating into the microphone
– May need to adjust how close to your mouth depending on how the gain is set
– If gain is too low screaming into the mike will not make your signal louder
More Noise and Interference
• When radio is in the car the generators a
boosters for spark plug voltage can produce
ignition noise – can make it hard to hear
message
– One reason Chris Pixton hates my cigarette lighter
hook-ups – lighter wiring picks up ignition noise
• Very likely to be a problem on HF, maybe side band (I use
FM on VHF)
– If you are getting ignition noise some radios have
a noise blanker that can be turned on to suppress
it (T5B06)
Dumby Loads Don’t Mean Your
Stupid
• Sometimes you need to trouble shoot or adjust a
radio
– If you transmit before things are set it will send out an
annoying signal (this is especially an issue on HF)
– The Purpose of a Dumby Load is to avoid sending
out signals while doing tests on a radio (T9A05)
• Dumby load acts just like an antenna but it has no radiating
elements
• Suggestion on special equipment items
– SWR meters dumby loads frequency counters
– Don’t everyone go and buy – a few people can buy,
share and help others
• I have most basic radio diagnostic toys