One of the reasons why ham radio is a great hobby is because you can participate in so many different modes of communication. The "mode" is simply the way that you transmit. Here are the following categories of modes and emissions:
Morse Code: Also called "CW" for "continuous wave" or telegraphy. This is where radio started. Morse code requires the use of a telegraph key; the key is hooked up to your transmitter and turns an unmodulated carrier frequency signal on and off. The "dits" and "dahs" are the signal turned on, while the blank spaces in between have to signal. CW, along with SSB, are your best bets for long range communications (DX). Because they take up little bandwidth, these signals are apt to retain integrity with little signal loss. CW can also be produced by tone modulation, which is feeding an on/off keyed tone into the transmitter. Tone-modulated CW is very inefficient and is recommended only during an emergency.
A rule of thumb of Morse code operation: only transmit at a rate that you feel comfortable interpreting. That is the rate that an experienced listener will use to respond with. If you give are not comfortable with deciphering at a fast speed, then you'll end up lost when he calls back.
If you really want to get into CW, put these items on your wish list:
Voice: Also known as "phone" emissions. Talking on radio through a microphone, which is hooked up directly to the transmitter. Phone transmissions include AM, FM and SSB. USB (upper side band) is commonly used for 10-, 12-, 15-, and 2-meter radiotelephony transmissions. LSB (lower side band) is used on 40-, 80- and 160-meters.
Radioteletype: Narrow band direct printing telegraphy emissions. Abbreviated as "RTTY", and is also known as radio-teleprinting. If you have ever seen just about any old cop flick, or Good Morning, Vietnam in the news room scenes with the twins, the printer that continuously prints out hard-copy data - that's an example of radioteletype. When operating RTTY, only operate as fast as the received signal.
RTTY requires a modem that is connected between a teleprinter or computer and your transceiver. If you are viewing this page, then you have the basic hardware needed to operate RTTY, all you need now is a transceiver and your ticket. RTTY is produced by frequency shift keying an RF signal. The maximum frequency shift permitted is 1kHz below 50 MHz; there is not maximum frequency shift regulated when operating RTTY above 50 MHz.
Packet: Where computer meets ham radio. You can hook up your radio to a terminal node controller (TNC), which is installed between the computer and transceiver at the microphone input, and send and receive data just like you can with a common internet service, except you are using the ham bands as the transmission medium instead of a "landline" network.
Both RTTY and packet radio require fast transmitting / receiving switching in order to shuffle digital data. Both of these modes hold the advantage of high speed transmission of data and communications reliability. Digital transmission speed (maximum symbol rate, or MSR) is measured the same way that you measure modem speed, by bauds. This differs, depending on what frequency that you are operating on. For 10-meters, the MSR is 1200 bauds; on 6- and 2-meters, the MSR is 19.6 kilobauds. Above 222 MHz, the MSR stretches 56 kilobauds - that's equivalent the landline data transfer technology that you are probably using right this minute..
Some packet terms:
Television: You can even send out fast-scan or slow-scan images by using ham radio. Why not? That's the way that the big networks do it! To receive AMT (Amateur Television), all you need is a cable-ready TV receiver.
Data: A cover-all designation for telemetry (CW), telecommand, and computer communications emissions. Telecommand is a type of emission used for amateur control of radio aircraft (no identification is required except transmitter labeling, restricted to 1 watt of power).
Modulated CW (MCW): Emissions produced by an on/off keyed FM audio tone. This is the same CW that you may have heard emitted from a repeater for identification.
Test: The designation for unmodulated carrier wave emissions.
When we discussed bandwidths, we told you that some modes would take up more bandwidth than others because they contained more information. The FCC regulates the size of these bandwidths, and they can only be so wide. The FCC bandwidth allowance for RTTY, data, or multiplex on 6- and 2-meters is 20 kHz. Look at how average transmissions compare in the table below:
The modes of transmission listed in order from narrowest bandwidth to widest bandwidth are: 1) CW, 2) RTTY, 3) SSB voice, then 4) FM voice.
TYPES OF AMATEUR RADIOS
There are three general categories of radios, all of which have differing properties and abilities based on what you get and where you get it. What is really great is that because radio circuits have become so compact, even some of today's handhelds have the capability for letting you go packet, RTTY, CW and ATV: