CW (continutious wave) or Morse Code
A series of long and short tones with roughly a 3:1
ratio for character length of dots to dashes. Each long or short tone is called an element, and a character is made
of one or more elements. (i.e. the letter "E" is made of one short tone, while the letter "X" is made of a dash-dot-dot-dash
combination) Morse Code has been around since before radio (more than 170 years). The letters are sent by switching
on and off a transmitter.
AM or Amplitude Modulation
This was one of the first voice modes. It uses
a microphone to modulate the signal of a transmitter. It changes the power or amplitude of the signal. The signal
consists of a carrier, and a upper, and lower mirror image side bands. These side bands contain the information
we use for audio.
SSB or Single Side Band
This is a more efficient version of AM. Here
we remove the carrier, and one of the side bands. All of the power used is only on the one side band, and not on the
carrier or extra side band. ( remember both side bands are mirror images of each other ) A 4 watt SSB transmission is
simmilar to a 12 watt AM transmission in strength. SSB comes in either USB ( Upper Side Band) or LSB (Lower Side Band).
This mode is very common on the HF band ( 3Mhz - 30 Mhz), and on DX VHF ( Distant Station 30 Mhz - 300 Mhz).
FM or Frequency Modulation
FM is where you use a microphone to modulate a transmitter.
For example, if you are on 146,000,000 cycles per second, (same as 146Mhz) and your voice range is roughly 5000 cycles per
second, the range might be from 146,002,500 to 145,997,500 cycles per second. Anyway you are changing the frequency,
and this has less noise than AM. This mode is also known as PM or Phase Modulation.
PSK31 or Phase Shift Keying at 31 bauds
This is one of many computer sound card modes.
This mode shifts the phase of a signal at about 31bauds. Roughly this is a comfortable typing speed for most people.
PSK31 is a popular keybord to keybord mode. Noise does not effect this mode much, and uses a signal that is only 31
hertz (or 31 cycles per second) wide. This makes it one of the few modes that can rival Morse Code. But is done
in SSB mode.
SSTV or Slow Scan TV
This is a way we send pictures back, and forth on Ham
Radio. We like to send picture of ourselves, friends, family, ect. We used to need all kinds of expensive equipment,
but with a computer it has been very simple. This is mainly, now, another sound card mode. But this is done in
SSB or FM, and there are several versions.
ATV or Amateur TeleVision
This is mainly done the same way as comercial TV, and
even uses a lot of the same equipment. If you own a cable ready TV, and a High Gain TV antenna, you already have the
equipment you need to receive ATV. But to send, you need the right type of transmitter, a TVcamera, and Microphone.
Many Hams have a lot of fun with this.
Amateur Satelites
These are also known as AMSATS or OSCAR's (Orbiting
Satelites Carrying Amateur Radio) Most receive on one band, and transmit on another. Some use FM, some SSB, and
other's use digital modes. This can be a lot of fun, but also a little tricky at first. You have to compensate
for doppler shift, and faraday rotation, as well as track this satelite correctly across the sky. Don't worry, many
have sucessful conversations with nothing more than a high gain, hand held antenna, and a portable radio.
Packet Radio
This is where you use a radio, a computer, and a "radio
modem" or TNC to send andn receive computer packets using the AX.25 protocol. This is handy to hook up to a local DX
cluster. ( a computer / radio bulletin board stating recently heard distant stations on HF) You can use this to send
and receive mail from other hams. I strongly recommend getting help on setting up a packet station, as there is a lot
to learn.
APRS or Automatic Packet Reporting Station
APRS is very popular. Here you use a TNC, radio,
and a GPS. Your radio sends out your location for other to track, and can be viewed on the internet. You can also
send, and receive messages to each other. Loved ones can see your progress on those long trips to see you are safe.
Or can be used to verify locations for public events. This can be handy for many resons. The national US frequency
is 144.390Mhz.
Digital Modes
Many of these require a TNC, but some can be done via
a computer sound card. These include PSK31, CW, AMTOR, RTTY, Clover, Packet, FAX, SSTV, PACTOR, OLIVIA, Hellscheiber,
MT63, FSK31, MSFK, Throb, and many others. These range from sending pictures, and text, to sending real e-mail via ham
radio.
RTTY or Radio TeleType
This mode has been around for a long time, and is still
very popular. It is a way of using a radio to send / receive text. PSK31 also sends text, but in a differend way.
RTTY has 2 tones, one for "Mark," and one for "Space." one of these two 2 tones is always transmitted, and sounds much
like 2 CW conversations going on at the same time.
