World of Ham Radio 1997/WOHR97_AmSoft_(1997-02-01).iso/packet/docs/packet01.doc

Text File | 1997-02-01 | 4KB | 60 lines

INTRODUCTION TO PACKET RADIO - PART 1 - by Larry Kenney, WB9LOZ

Packet Radio is the latest major development to hit the world of Amateur
Radio.  If you haven't already been caught by the "packet bug", you're
probably wondering what it's all about and why so many people are so
excited about it.  Well, continue reading, because you're about to find
out.

Packet seems to offer something different from other facets of Amateur
Radio, yet it can be used for everything from a local QSO to a DX contact
2500 miles away (on 2 meters!), for electronic mail, message transmission,
emergency communications, or just plain tinkering in the world of digital
communications.  It presents a new challenge for those tired of the QRM on
the low bands, a new mode for those already on FM, and a better, faster
means of message handling for those on RTTY.  Packet is for the rag chewer,
the traffic handler, the experimenter, and the casual operator.

A ham can get involved very easily with relatively small out-of- pocket
expenses.  All you need is a 2-meter transceiver, a computer or terminal,
and a TNC.  You probably already have the two meter rig and a computer of
some kind, so all you need to buy is the TNC, which costs just over $100.
The TNC is the Terminal Node Controller, the little black box that's wired
between the computer and the radio.  It acts very much like a modem when
connecting a computer to the phone lines.  It converts the data from the
computer into AFSK tones for transmission and changes the tones received by
the radio into data for the computer.  It's a simple matter of wiring up a
plug and a couple jacks to become fully operational.

Packet is communications between people either direct or indirect.  You can
work keyboard to keyboard or use electronic mailboxes or bulletin board
systems to leave messages.  Due to the error checking by the TNC, all of it
is error free, too.  (That is, as error free as the person at the keyboard
types it.)  As the data is received it's continuously checked for errors,
and it isn't accepted unless it's correct. You don't miss the information
if it has errors, however, because the information is resent again.  I'll
go into how this is accomplished in a later part of this series.

The data that is to be transmitted is collected in the TNC and sent as
bursts, or packets, of information; hence the name.  Each packet has the
callsign or address of who it's going to, who it's coming from and the
route between the two stations included, along with the data and error
checking.  Since up to 256 characters can be included in each packet, more
than three lines of text can be sent in a matter of a couple seconds.
There is plenty of time between packets for several stations to be using
the same frequency at the same time.

If all of this sounds confusing, don't let it bother you, because that
little black box, the TNC, does everything for you automatically.  Packet
might seem very confusing at first, but in a day or two you're in there
with the best of them.   In this series I'll be telling you more about
packet--how you get on the air, how to use it to your best advantage, and
ways to improve your operation.   We'll talk about that little black box,
the TNC, and tell you about all its inner-most secrets.  We'll discuss
mailboxes, bulletin board systems, and the packet networks that allow you
to work stations hundreds of miles away using just a low powered rig on 2
meters, 220 or 450.  The world of packet radio awaits you!

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