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From: clements@bbncd1.arpa (Bob Clements)
Newsgroups: net.ham-radio
Subject: Re: Ham Programs & BBoards
Message-ID: <8357@brl-tgr.ARPA>
Date: Wed, 20-Feb-85 15:21:28 EST
Article-I.D.: brl-tgr.8357
Posted: Wed Feb 20 15:21:28 1985
Date-Received: Tue, 26-Feb-85 08:20:24 EST
Sender: news@brl-tgr.ARPA
Organization: Ballistic Research Lab
Lines: 54

Walt,

I can't help much with your question about logging, beam heading or
board design programs.  But I can chew your ear off about packet
radio at any length you want.

The basic setup of packet radio as it has evolved so far is that each
ham has a terminal or a little computer with a terminal emulator
program, and he has a TNC (Terminal Node Controller) and a radio,
usually 2 meters but also HF and other VHF bands.

The TNC is a single board computer with a modem, transmitter control,
serial ports, protocol and so on all ready to go.  The hookup is
literally a terminal on one side (DB25 connector) and three signals
to the radio on the other side, namely transmit audio, receive audio
and push-to-talk. TNC's are available from TAPR, GLB, AEA, and some
others, and according to the Gateway that just came out, they will be
available from Heathkit.

Most packet radio operation is simplex (145.01 MHz on most of the
East Coast).  To get farther than your own neighborhood, you
relay through other stations, also on the same simplex channels.
Your TNC allows others to relay through you. This is called
"Digipeating". Typically, a club will put up a digipeater at a
good site and everybody can digipeat through it or go directly to
those in their neighborhood.

The thing that comes as a surprise to most 2-meter operators is that
a dozen or so QSO's can be going on at once, all on the same simplex
frequency, without interference. This is because each station sends
only an occasional short burst of data when the operator finishes
typing a line. Most of the channel time is idle. If two stations
happen to transmit at once, so that a transmission is lost in
the QRM, the protocols in the TNC take care of re-sending the packet
until it gets through.

To keep interest up in the area, it is good to establish a Mailbox
or Bulletin board system.  Most of these (about 25 and climbing) are
based on the Xerox 820 boards that were available a while ago. They
use software developed by Hank, W0RLI. Many of these are linked
together by HF on 20, 30 and 40 meters.  I have posted the W0RLI
software on SIMTEL20. (It's about time to send an update, now that
I think of it. The new features of automatic mail forwarding among
BBS's aren't in the current one on SIMTEL20.) Hank's software
has been mentioned in Gateway and 73 magazine.

I'll cut this message short here. Let me know if I can expand on
any of this for you. I guess I'll CC: this to info-hams, too.
Anybody on the list who wants to chat about Packet Radio and
packet BBS's, please do!

73,
Bob Clements
(K1BC)