What is packet radio?
Playing around on packet radio is very similar to playing around on the internet.
That is, there is usually a computer terminal (although not always necessary), a
modem and somebody else to talk to. The difference is that in packet the information
is transmitted via radio signals rather than over telephone lines.
- Transmitting a packet signal:
- Information is typed into the computer terminal's buffer.
- After the send command is hit, the buffer dumps the information into the modem.
- The modem converts the information it has just received from the computer into
two audio tones that turn on and off according the the ASCII standard.
- These tones are fed into the microphone input on the radio, which automatically turns
on the transmitter when there is a signal coming through to be transmitted.
- The radio signal makes it to another station where it is received.
- Receiving a packet signal:
- The packet radio signal is received by the antenna.
- The radio demodulates the signals so that all that is left are the audio tones that
were produced by the originating station.
- These tones are fed from the radio into the modem.
- The modem decodes the tones that the radio sent it, turning them into information that
sends to the computer's buffers.
- The buffers on the computer are dumped onto the screen, where the information that was
sent can be viewed.
How do I get started?
Getting started in packet radio requires some equipment:
Connect everything together, read over the manual that came with the modem, install the
software, find a recognized packet frequency in your area and go for it.
- a radio--on the band you wish to use packet (2 meters is most often used)
- a packet radio modem--not a telephone modem (packet radio has different standards than
ma Bell has)
- a computer--either laptop or desktop
- a pakcet radio program--available through many sources or downloadable from TAPR
- cables to connect the radio to the modem and the modem to the computer
But the cost, you say? Don't worry too much...if you have the radio and the computer,
you have the most expensive parts. A modem that will work for packet can be had new
for roughly $120, and you can get a real deal on old PK-88's at hamfests. These modems
still work, and they do their job very well.
What are some practical uses of packet radio?
- faster, more efficient transmission of data
- packet has error detection, so you don't have to worry too much about letters getting
transposed or changed altogether
- increases efficiency of emergency communications
- when used with APRS, exact location as well as information
that the operator must pass can be very quickly determined
- very fast dissemination of high priority information
- boost field day scores
- won't keep people up at night listening to your voice
- while not exactly limitless, packet radio is very efficient, as stated, and so is very
well suited to emergency communications
A brief history of packet radio
I don't have that yet, so come back some other time and I should have it up.
Packet radio links
- TAPR--the Tuscon Amateur Packet Radio club
Questions? Mail them to firstname.lastname@example.org
Last modified: 4/24/98