QRZ! Ham Radio 8/QRZ Ham Radio Callsign Database - Volume 8.iso/pc/files/mac/pktutor.hqx/Packet Tutor/packet.all

Text File | 1990-10-11 | 101KB | 1,824 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!

- - - -

INTRODUCTION TO PACKET RADIO - PART 2 - by Larry Kenney, WB9LOZ

In the first part of this series we told you, in general terms, what packet
radio was all about...what it is, its uses, the equipment used and,
generally, how its transmitted.  Now we're going to tell you how to get on
the air, make a QSO, and become familiar with your packet station.  Whether
you're new to packet, having just received a new TNC, have been involved
for just a short time, or are one of the "old timers" with four or five
years of experience, this series should help all of you.  Even if you don't
yet own a TNC, you should keep this article handy for future use.  I'll bet
you'll be joining us soon!

The equipment needed to get on the air is a VHF transciver, a computer or
terminal, and a TNC - the terminal node controller - the little black box
we talked about in part 1.  (There is packet activity on HF, but VHF is
where all the action is.  It's the best place to start out in packet.)  The
TNC contains a modem and is equivalent to the modem used to connect your
computer to the phone lines, except that it also contains special software
that's specially designed for ham radio packet use.

When you buy a TNC and take it out of the box, you'll find cables supplied
for connecting it to the radio, but you'll have to attach the appropriate
mic and speaker jack connectors for the radio you're going to use.  You
also have to furnish the cable that connects the TNC to your computer or
terminal.  In most cases, the standard RS-232 port is used between the TNC
and computer, however this varies with the type of computer and TNC used.
The operating manuals supplied with the TNCs have a good write up on the
various computers and the cabling needed.  I would advise that you read the
introduction and set up procedures for your particular TNC very carefully.
Most companies have supplied excellent manuals, and you usually can figure
out all of your set up problems from the the information supplied in the
manual.

Once you have everything wired and connected together, turn on the
computer, load a terminal program (anything used for a phone modem will
work well for packet) and get into receive mode.  Now turn on the radio and
make sure the volume is turned up about a quarter turn (about the "10 or 11
o'clock" position) and make sure the squelch is set.  It should be at the
point where the background noise disappers, just as it would be set for a
voice QSO.  Next, turn on the TNC.  You should get a "greeting" or sign on
message showing the manufacturer's name, software version, etc.  If you see
a bunch of gibberish, such as &tf$d.#ssan>m, it means that the data rate of
the TNC and computer are not the same.  This data rate is better known as
the baud rate. The baud rate of the TNC has to match the baud rate used by
your computer terminal program and is easily adjusted.  Check you TNC
manual for this procedure, as it varies from TNC to TNC.  If you don't see
a "greeting" or the gibberish, check your cables and connections.  Make
sure that you have everything connected properly, that the right wires are
on the right pins, etc.

Now we need to explain the three levels of communicating you can do from
the keyboard.  First, you can communicate with your computer for setting up
the terminal program; second, you can communicate with the TNC; and third,
you can communicate with the radio.  It's very important that you know
which level you're in when working packet.  I can't help you much with the
computer level, since that varies with manufacturer, model and the terminal
program you're using, but once you get the terminal program ready to
receive data, you're ready to talk to the TNC.

First, do a "control C" (press the CNTL and the letter C simultaneously);
this puts the TNC in COMMAND mode, the level where you communicate directly
with the TNC from the keyboard.  You should see "cmd:" on your screen.
Enter:
MYCALL - - - -
with your callsign in place of the dashed lines, such as MYCALL WB9LOZ
followed by a carriage return (CR).  All commands are followed by a (CR).
This sets into the TNC memory the call that you're going to use on the air.
Now if you type MYCALL (CR), it should respond with your call.  If it does,
you've proven that the computer to TNC linkup is working fine.  If you do
not see anything on the screen when you type, blindly enter the following:
ECHO ON (CR).  If you see two of everything that you type, such as
MMYYCCAALLLL, enter ECHO OFF (CR).

You're now ready to go on the air!  Tune the receiver to any odd numbered
frequency between 144.91 and 145.09 that has some activity on it and set
the rig up for simplex operation.  Enter MONITOR ON (CR), then watch the
screen.  You should soon be seeing the packets that are being sent over the
air by other stations.  If you don't see anything in a minute or two, try
tuning to another frequency.  Watch for callsigns with a * next to it, such
as  W6PW-1*, WA6RDH-1*, or WB6SDS-2*.  Callsigns with an asterick indicate
that you're copying the packet from that station, as it's being repeated,
or digipeated, by a packet repeater.  Jot down the call.

In packet, you can have up to 16 different stations on the air at the same
time using the same callsign.  That's where the numbers in the callsign
come into play.  The calls W6PW, W6PW-1, W6PW-2, W6PW-3, W6PW-4 and W6PW-5
are all individual stations operating under the same station license.  A
callsign without a number is the same as -0. The numbers are used to
differentiate between the various stations.

Now, before you try to make your first QSO with someone else, you should
check out your equipment to make sure it's set up properly.  To do that,
you can CONNECT to yourself.  Note one of the callsigns you jotted down a
minute ago.  Make sure your radio is still tuned to the frequency where you
heard that call, then enter the following:
C - - - - V - - - - (CR)
where the first dashed lines are YOUR callsign and the second dashed lines
are the call of the station you jotted down.  The C means CONNECT and the V
means VIA.  C WB9LOZ V W6PW-1 means connect to WB9LOZ via W6PW-1.  You
should soon see "*** CONNECTED TO (your call)" on the screen.  You have now
entered the third level of communications, called CONVERSE mode, and this
is where you communicate from the keyboard to the radio.  Anything you type
on the keyboard will be transmitted over the air as a packet every time you
hit a (CR).  If you enter "Test" (CR) you should see "Test" a second time
on the screen, as it's transmitted, then digipeated and sent back to you.
In this case you'll only be talking to yourself via another station, but
it's a good way to check to make sure your system is working properly.  If
that works, hit a CONTROL C.  This puts you back into COMMAND mode where
you talk to the TNC again.  Enter D (CR).  This will disconnect you from
the other station, and you'll see "DISCONNECTED" on the screen.

Now you're ready to talk to someone else!  Watch for a familiar call on the
screen while monitoring or note calls you see frequently.  Be sure to note
whether or not a digipeater is being used by watching for the *.  If you
see WB9LOZ > WA6DDM, W6PW-1*, for example, you're receiving the packets
from W6PW-1.  If you do not see an asterick, you are copying the station
direct.  When the station you want to contact is finished with his QSO,
enter:
C - - - -   or
C - - - -  V  - - - - (depending on whether or not a digipeater is needed)
followed by (CR).    You should get a "*** CONNECTED TO ..." on the screen,
which means you're in converse mode, and your first QSO with someone else
is underway!  Anything you type now will be sent to the other station, and
anything he types will be sent to you.  When you're finished, be sure to do
a CONTROL C to get back into command mode, then enter  D  to disconnect
from the other station.

You're on the way now to lots of packet fun and adventure!  If you are
still having problems at this point, contact a friend that has some
experience on packet and ask for help.  The initial set up of the computer,
TNC and radio is probably the biggest stumbling block in packet.  Any
experienced packeteer will be happy to help you get through this process to
get you on the air.

- - - -

INTRODUCTION TO PACKET RADIO - PART 3 - by Larry Kenney, WB9LOZ

In Part 2 I talked about how to get on the air and make your first QSO.
Now let's take a look at some of the commands that are available in your
TNC to help improve your station operation.

TNC COMMANDS: The TNC, or Terminal Node Controller, that "little black box"
we've talked about in the past, has more than 100 different commands for
you to use.  You're able to customize your packet operating with these
commands and turn on and off various features as you wish.  Not all TNCs
are exactly alike, but all have pretty much the same functions. I'll be
using the commands used by the TNC2 and clones in my examples.

We covered a few of the commands previously: CONTROL C for entering command
mode, MYCALL, MONITOR, CONNECT, and DISCONNECT.  Now let's discuss a few
that can change the way your station functions.

  ECHO: This command tells the TNC whether or not it should send what  you
type back to the monitor screen.  If you don't see anything when  you type,
set ECHO to ON.  IIff yyoouu sseeee ddoouubbllee, like that, set ECHO to
OFF.  This setting will depend on how your particular computer system
functions.

  CONV (converse mode): Your TNC will automatically switch to this mode
when you connect with someone, but you can also do it by entering CONV (CR)
at the Cmd: prompt.  When in converse mode, anything you type will be
transmitted via the path you set with UNPROTO.  (See the next paragraph.)
Anyone in monitor mode will be able to read what you transmit.  Packets in
converse mode are sent only once and are not acknowledged, so there is no
guarantee that they'll get through.  This mode is used frequently for
sending CQ's.

  UNPROTO: This command designates the path used when in converse mode. The
default is CQ, but you can enter a series of digipeaters if you wish, or a
specific group or club name.  Some examples:
       CQ v WB6SDS-2,W6SG-1,AJ7L      SFARC v W6PW-1,W6PW-4
Remember, you have to change UNPROTO for use on different frequencies,
unless you leave it set simply to "CQ".

  FRACK: This determines how long your TNC will wait for an acknowledgement
before resending a packet.  It shouldn't be set too short, or you simply
clutter up the frequency, yet it shouldn't be too long, or you'll spend too
much time waiting.  I use FRACK set to 7, and have found that to be an
overall good value.

  DWAIT: Used to avoid collisions, DWAIT is the number of time units the
TNC will wait after last hearing data on the channel before it  transmits.
I have DWAIT set to 16, and have found that to work well.

  PACLEN: Determines the number of characters in your packets, ranging from
1 to 256.  The more characters you send per packet, the longer it takes to
transmit the information and the greater your chances are of noise,
interference or another station wiping it out. I've found a PACLEN of 80,
which is the length of one line, to be a good  value.  When working a
station nearby, PACLEN can be increased.  When working a distant station,
it should be decreased.

  RETRY: Your TNC will retransmit a packet if it doesn't receive an
acknowledgement from the station you're working.  RETRY indicates the
number of times the TNC will try to get the packet through before  giving
up and disconnecting.  This can be set from 1 to 15, but I've found 8 to 10
to work well.  Less than that causes an unnecessary disconnect if the
channel happens to be busy, but more than that clutters up the channel.

The following TNC commands affect the monitoring mode and what you see on
the screen:

  MONITOR: This must be ON for you to monitor anything.  When ON, you see
packets from other stations on the frequency you're tuned to.  What packets
you see is determined by other commands from the list below.  If MONITOR is
OFF, you see only packets sent to you while you're connected to another
station.

  MALL: If MALL is ON, you receive packets from stations that are connected
to other stations, as well as packets sent in unproto (unconnected) mode.
This should be ON for "reading the mail". If MALL is OFF, you receive only
packets sent in unproto mode by other stations.

  MCOM: If ON, you see connect <C>, disconnect <D>, acknowledge <UA> and
busy <DM> frames in addition to information packets.  If OFF, only
information packets are seen.

  MCON: If ON, you see packets from other stations while you're connected
to someone else.  This can get very confusing, but is useful when your path
is bad and you want to see if your packets are being digipeated okay.  If
OFF, the monitoring of other stations is stopped when you're connected to
another station.

  MRPT: If ON, you see a display of all the stations used as digipeaters
along with the station originating the packet and the destination station.
If OFF, you see only the originating and destination stations.  For
example, if you have MRPT ON, you might see a transmission such as this:
  K9AT>WB6QVU,W6PW-5*: I'll be leaving for the meeting at about 7:30.
If MRPT was OFF, the same transmission would look like this:
  K9AT>WB6QVU: I'll be leaving for the meeting at about 7:30.
In the first case, you can see that the W6PW-5 digipeater was being used.
The asterick indicates which station you were hearing the packet from.  In
the second case you have no idea if digipeaters are being used or what
station you were receiving.

  HEADERLN: If you have this turned ON, the header of each packet is
printed on a separate line from the text.  If OFF, both the header and
packet text are printed on the same line.

  MSTAMP:  Monitored packets have the date and the time the packet was
received if MSTAMP is ON.  If it's OFF, the date/time stamp is not shown.

I run my station with all of these commands, except MCON, turned ON so that
I can really see what's happening on the frequency I'm monitoring.  Try
various combinations of these commands and then decide on the combination
you like best for your station.

- - - -


INTRODUCTION TO PACKET RADIO - PART 4 - by Larry Kenney, WB9LOZ

USING DIGIPEATERS AND NODES:

DIGIPEATERS:
Digipeater is the term we use to describe a packet radio digital repeater.
Unlike the FM voice repeaters, most digipeaters operate on simplex and do
not receive and transmit simultaneously.  They receive the digital infor-
mation, temporarily store it and then turn around and retransmit it.

Your TNC will allow you to enter up to eight digipeaters in your connect
sequence, but using more than 3 usually means long waits, lots of repeated
packets, and frequent disconnects, due to noise and other signals encount-
ered on the frequency.

When entering the list of digipeaters in your connect sequence, you must
make sure that you enter them in the exact order that your signal will use
them.  You must separate the calls by commas, without any spaces, and the
EXACT callsigns must be used, including the SSID, if any. That means you
need to know what digipeaters are out there before you begin randomly
trying to connect to someone.  Turn MONITOR ON and watch for the paths that
other stations are using.

Here are some examples of proper connect sequences:
C W6PW-3 v W6PW-1
C N6ZYX v WA6FSP-1,WB6LPZ-1
C W6ABY-4 v K6MYX,N2WLP-2,AB6XO
The "v" means via.  In the first example the sequence shown means: Connect
to W6PW-3 via W6PW-1.

Something to remember when using digipeaters is the difference between
making a connection and sending information packets.  If the path isn't all
that good, you might be able to get a connect request through, but will
have a difficult time with packets after that.  The connect request is
short so it has much less of a chance of being destroyed by noise or
collisions than a packet containing information.  Keeping information
packets short can help keep retries down when the path is less than ideal.

NODES:
Net/Rom, TheNet, G8BPQ packet switch and KA-Node are names that refer to a
device called a packet node, another means of connecting to other packet
stations.  Later on in this series you'll find a complete review of node
operation, but for now we'll cover the basics so that you can begin using
the node network.  The difference you should note here is that you connect
to a node rather than using it in a connect path as you do with a digi-
peater.

First, you need to determine what nodes are located close to you.  You can
do this by monitoring and watching for an ID or by watching to see what
other stations in your area are using.  You'll note that most nodes have an
alias ID in addition to its callsign.  Once you determine the callsign or
alias of a local node, you connect to it the same way as you connect to any
other packet station.  You may use either the callsign or the alias to make
the connection.  For example, the node I operate has the alias ID of SF and
the callsign of WB9LOZ-2, so you could connect to it using "C SF" or
"C WB9LOZ-2".  Either one will work.

When you connect to a node, your TNC automatically switches to converse
mode, just like when you connect to any packet station.  Anything you now
type is sent to the node as a packet, and the node acknowledges each packet
back to your TNC.  For the remainder of your connection your TNC works only
with this one node.

To use the node network to connect to another local station, you simply
enter a connect request as though you were connecting direct from your TNC,
such as "C WB9LOZ".  You do this, however, while you ARE STILL CONNECTED TO
THE NODE.  The node will then retransmit your connect request and you'll
receive one of two responses:  "Connected to (callsign)" or "Failure with
(callsign)".  Once you're connected you hold your QSO just as if you had
connected direct or via a digipeater.  When you're finished, go to command
mode on your TNC (Control C) and enter "D" (CR) and you will be discon-
nected from the node and the station you were working.

(NOTE: If the node you're using is a G8BPQ packet switch, it might have
several frequency ports.  You'll have to enter a port number between the C
and the callsign in your connect request to indicate the frequency you want
to use, such as "C 2 WB9LOZ".  Enter "PORTS" for a port list.)

When you're connected to a node enter "NODES" <CR> and you'll receive a
list of other nodes that you can reach on the network from the node you're
using.  You'll note that the node list will vary in length and in the calls
listed as you move from frequency to frequency, since all frequencies are
not linked together.  The list gives both an alias ID and a callsign for
each node.  The alias ID often gives you a hint as to where the node is
located, but not always.  To find out for sure where a node is located
you'll need to get a copy of the descriptive node listings that are avail-
able on most packet bulletin board systems.  These complete lists give the
alias, callsign, location, frequency and other information on each node in
the network.

To connect to a station in another area using the node network you first
must determine which node is closest to the station you want to work.  For
demonstration purposes, let's say we want to connect to N6ZYX.  He's told
you he uses the the W6AMT-3 node, so you check the node list and see that
SFO3:W6AMT-3 is listed.  WHILE STILL CONNECTED TO YOUR LOCAL NODE you first
connect to the distant node by sending a normal connect request, in this
case "C W6AMT-3".  Your TNC will send this as a packet to your local node
and your local node will acknowledge it.  The network will then go to work
for you and find the best path between your local node and the one you're
trying to reach.  You might have to be a little patient here, as it some-
times takes a few minutes for the connection to be completed.  You'll then
see one of two responses: "Connected to W6AMT-3"  OR  "Failure with
W6AMT-3".  If it can't connect for some reason, try again later.  It could
be that W6AMT-3 is temporarily off the air or the path has decayed and is
no longer available.  We're going to be positive here and say we received
the first option.

Once you're connected to W6AMT-3, enter "C N6XYZ".  Again, your TNC will
send this as a packet to your local node and the local node will acknowl-
edge it and send it down the path to W6AMT-3.  W6AMT-3 will then attempt
to connect to N6XYZ.  Here again you'll get one of the two responses:
"Connected to N6XYZ"  OR  "Failure with N6XYZ".  If you get connected,
you hold your QSO just as you normally would, but there's one BIG
difference -- your TNC is receiving acknowledgements from your local
node, and N6XYZ is receiving acknowledgements from W6AMT-3.  The acknowl-
edgements do not have to travel the entire distance between the two end
stations.  Each node in the path handles the acknowledgement with the next
node in line.  Because of this, retries are greatly reduced, and your
packets get through much faster.

When you're finished with the QSO, you disconnect in the normal manner --
go to Command Mode on your TNC and enter "D" <CR>.  The entire path will
then disconnect automatically for you.

Nodes offer a variety of other features besides allowing you to connect to
other stations, and we'll look at those in parts 10 and 11 of this series.

- - - -

INTRODUCTION TO PACKET RADIO - PART 5 - by Larry Kenney, WB9LOZ

USING A PACKET BULLETIN BOARD SYSTEM: This information is based on W0RLI
software, so the instructions might vary slightly for users of AA4RE,
WA7MBL, MSYS or other type systems. Use the H - HELP command on your BBS if
some of these commands do not work as described here.

You connect to a bulletin board system (BBS) exactly the same way as you
connect any other station.  Once connected, you'll receive a welcoming
message, some information on the BBS and instructions.  This information
will vary from system to system.  Read the information and instructions
carefully.  The first time you connect you'll receive a request to enter
your name, QTH, zip code and home BBS for the system user file.  On some
systems, the software will not let you do anything else until you have
entered this information.  When you receive the welcoming message, you'll
note that the last line ends with a >.  This is known as the prompt, and is
where you enter the command you want performed next.

You enter your name using the letter N followed by a space and then your
first name, such as: N Larry.  Your QTH is entered using NQ followed by a
space then your full city name and two letter state abbreviation, such as:
NQ San Francisco, CA.  You enter your zip code with NZ followed by a space
and your five-digit zip.  Your "home BBS" is the system that you plan to
use regularly and want all of your personal messages delivered to.  Make
sure that it's a full service BBS, not a personal mailbox, since only full
service systems are included in the message forwarding network.  You enter
your home BBS by typing NH followed by a space and then the call of the
BBS, such as NH W6PW. (Note: SSIDs are not used with BBS operation except
for when making the connection.  The BBS software ignores all SSIDs.)  This
user information is stored at the local BBS and is also sent to a central
data bank known as the "White Pages Directory".  The information can be
accessed by anyone.  System operators (sysops) use it for determining your
home BBS when forwarding messages, and you can use it to find the name, QTH
and home BBS of your friends.  How to use the "White Pages" will be
discussed in part 9 of this series.

When checking in to a BBS for the first time, you should become familiar
with the commands available to you.  Each BBS or mailbox is a little
different from the next, so read the introduction carefully and follow the
directions.  If you don't know what to do next, enter H for the HELP
instructions.  Make note of the command letters, enter only one command at
a time, and make sure you enter them correctly. Computers are not very
forgiving and expect things to be entered in proper form.  Take your time,
check out the features that the BBS offers and enjoy yourself.  There's no
need to feel rushed or intimidated.  If you get to a point where you don't
know what to do next, don't give up and disconnect, enter H again for
further HELP.  That's what it's there for!  I suggest that you make a
printer copy of the complete help file so that you have it available as a
reference when using the BBS.

Now let's go through the basic procedures you should follow when checking
into a BBS.  If there are personal messages addressed to your call, the BBS
will list them for you following the welcome message.  Note the message
numbers.  At the > prompt, the first thing you should always do is list the
new messages, by entering L.  The BBS program updates the user file each
time you check in, logging the latest message number.  The next time you
check in, only new messages that have been received by the system will be
included in your list.  The first time you'll receive all of them, since
they're all new to you.  This list can be very long, as many systems have
more than 200 active messages on line.  When you receive the list, note the
numbers of the messages you're interested in reading.

Next, read the messages you're interested in.  You do this by entering
R XXXX, where the Xs represent the message number, such as R 4521.  Note
that there is a space between the command and the number.  It's best to
have your buffer or printer turned on when reading messages, because
they're apt to come in faster than you're able to read them.  You should
have a means of saving them for reading later after you've disconnected.
If there were messages addressed to you, you should erase or "kill" them
once you've read them.  You can do this with the "KM" command, which means
"Kill Mine".  This command will erase all messages that are addressed to
you that have been read.  You can also kill each message individually by
entering K XXXX, where the X's are the message number.

Once you've read all the messages you're interested in, you have several
options.  You can look back at old messages, send messages to other
stations, see what's available in the files section, download a file,
upload a file, check the list of stations that have recently checked in to
the BBS or stations that have been heard on frequency, monitor other
frequencies used by the BBS, use the gateway feature (if available), check
the status of the BBS tasks, or a variety of other things.

We look at the BBS commands in detail next.

- - - -

 INTRODUCTION TO PACKET RADIO - PART 6 - by Larry Kenney, WB9LOZ

In the previous section we discussed the basics of using a packet bulletin
board system.  Now let's look at the BBS commands in more detail.  This
information is based on the W0RLI software so some of the commands might
vary slightly on systems using different software, such as REBBS, MSYS,
WA7MBL, etc.  Use H (HELP) on your BBS if you find that a command doesn't
work as described here.

LIST COMMAND: The first thing you should do when logging on to a BBS is to
use the LIST command.  There are many variations available, but L, by
itself, is the one used most often.
     L (List) - Lists all new messages, except other users' personal
         messages, that have been entered since you last logged in.
If you want to list specific messages, you may use one of the following
variations of the L command:
     LM  - (List Mine) - Lists all messages addressed to you.
     Lx  - Lists all messages of the type designated by 'x'. Example:
           LB will list all bulletins.
     L # - Lists messages back to and including number #. Example:
           L 4050 will list all messages, except personal messages to
           others, from the latest one back to #4050.
     LL #- Lists the last # messages.  Example: LL 20 lists the last 20
           messages received at the BBS, excluding other's personal
           messages.
     L 1 - Lists ALL non-personal messages.
     L> callsign - Lists all messages TO callsign indicated. Example:
           L> N6XYZ
     L< callsign - Lists all messages FROM callsign indicated. Example:
           L< N6XYZ
     L@ designator - Lists all messages that have that "designator" in
           the @ BBS column of the message header.  Example: L@ ALLCAN
           will list all messages with ALLCAN in the @ BBS column.

READ COMMAND:  To read a message, you enter R followed by a space then the
message number.  Example: To read message 5723, you'd enter: R 5723. You
also have the option of using the RH command, which will give you all of
the forwarding headers in detail, rather than just giving you the path.
Example: To read message 5723 with the full headers, you'd enter RH 5723.
There is one other version of the READ command, and that's RM.  Entering RM
by itself will give you all of the messages addressed to you that have not
yet been read.

ERASING MESSAGES:  Once you have read a personal message, please erase it.
The sysop will appreciate your help in clearing up "dead" messages. You use
the K - KILL command to do this.  You can enter K #, such as K 5723, which
will erase that particular message, or you can enter KM, which will erase
all of the personal messages you have read.  If you use the KM command, the
BBS will list the message numbers for you as they're killed.

THE "S" COMMAND:  S (Send) and (Status):  The letter S by itself will give
you a reading of the BBS status on W0RLI systems, showing the callsigns of
stations using the system, the time they connected, the ports and tasks
they're using, etc.  It also shows information on the messages waiting for
users and those waiting to be forwarded to other bulletin board systems.
S, by itself, on other systems will either prompt you for further
information on sending a message, or it will give you an "illegal command"
error prompt.

To use the "S" command for sending a message it must be further defined.
There are three types of messages found on a packet bulletin board system:
Personal, Bulletin, and Traffic.
    "SP" is used for sending a personal message to one other station,
    "SB" for sending a bulletin, and
    "ST" for sending a message that's going to be handled by the
         National Traffic System.
You're able to send a message to one particular person, to everyone on the
local BBS, to everyone at every BBS in Northern California, in Southern
California, in the entire state, or all across the entire country.  It all
depends on your addressing.

At the BBS prompt you enter the appropriate command (SP, SB, or ST)
followed by a space and then the addressee.  The addressee can be a
callsign or it can be something of a general nature, such as ALL, QST,
ARES, etc.  Examples:  SP WB9LOZ    SB ALL    SB SALE
All commands, of course, must be followed by a <CR>.

If you wish to send the message to someone at another BBS, you have to
indicate the call of the other BBS and the two letter abbreviation of the
state it's located in following the call of the addressee.  For example, to
send a message to N5PQ, who uses the W5XYZ BBS in Texas, you would enter:
   SP N5PQ @ W5XYZ.TX
The BBS call and the state abbreviation are separated by a period. This is
the bare minimum required for delivery of messages going out of state.  A
more complete system of addressing is available.  It's helpful in directing
your messages to stations in the U.S more quickly and is required for
messages going to stations outside of the U.S.  It's called hierarchical
addressing, and its covered in detail in the next part of this series.

To send a general message or bulletin to more than just the local BBS, you
need to use a designator in place of the BBS call.  The designator
indicates the area where you want the message distributed.  In northern
California,
    ALLCAN indicates that you want the message sent to all Northern
           California BBSs, which includes all of them from Santa Cruz,
           Gilroy, and Fresno northward.
    ALLCAS is used to send a message to all BBSs in the southern part
           of the state.
    ALLCA  is used for sending a message to EVERY BBS in the state.
    ALLUSW is used for distribution to CA, AZ, NV, OR, WA and ID.
    USA    is the designator to use for sending a message to EVERY BBS
           IN THE USA.  Extreme care should be used when using the USA
           designator.  Please make sure that the subject matter is of
           interest to packet users everywhere and please keep the
           message as short as possible.  "For Sale" messages should
           NOT be sent with the @ USA designator.  The National HF
           Packet Network is somewhat fragile, due to varying band
           conditions, so unnecessary traffic can keep more important
           traffic from getting through.
Here are a few examples of how you would correctly address a bulletin-type
message for general distribution:
   SB ALL @ ALLCAN   SB SALE @ ALLCA   SB QST @ ALLCAS   SB AMSAT @ USA

If you have traffic for the National Traffic System, you must use a special
format.  NTS messages are entered as ST ZIPCODE @ NTSXX, where the XX is
the two-letter state abbreviation.  Examples:
               ST 03452 @ NTSNH    ST 60626 @ NTSIL

When you have the address line of your message complete, you enter a
carriage return (<CR>).  You'll then receive a prompt asking for the
SUBJECT or TITLE of the message.  Enter a brief description of what the
message will be about, followed by a <CR>.  Next, you'll be asked to enter
the TEXT of the message.  When entering the text, you should insert
carriage returns at the end of each line, as if you were typing a letter.
A normal line has a maximum of 80 characters, so when you have 70 to 75
characters typed, enter a carriage return and continue on the next line.
This will prevent words from wrapping around to the next line and the
program inserting an unnecessary blank line in the text.  After you have
completed the text, you end the message with a CONTROL Z. (You send a
CONTROL Z by holding down both the CONTROL key and the Z key simultan-
eously.)  You must follow the CONTROL Z with a carriage return.  (Some
systems will also allow you to use /ex to end a message.)  When you receive
the BBS prompt, you'll know that the message has been accepted by the
system.

FILE DIRECTORY COMMANDS:
    W (What) - Entering W, by itself, gives you a list of the directories
available on the BBS along with an associated letter for each directory,
called the directory ID.
    Wd  - Gives a list of the files in the directory indicated by d. The
"d" is the directory ID you obtain with the W command.

   D (Download) - Used for reading files from a directory.  Must be used
with a directory ID and filename using the following form:  Dd filename
The "d", again, is the directory ID and the filename must be entered
exactly as listed in the directory.   Example:    DG FCCEXAM.INF

    U (Upload) - Used for uploading (sending) a file to the BBS.  The
command must be used with a directory ID, followed by the filename you're
assigning to the file, using the form: Ud filename.  The d indicates the ID
of the directory where you want to enter the file.  Filenames can have up
to 8 characters preceding the dot and 3 characters following the dot.
Example: UM FLEAMKT.INF would upload a file named FLEAMKT.INF into the
directory with the M ID.  The BBS program will not allow you to upload a
file with a filename that already exists, and some directories are set by
your local sysop for downloading only.

GENERAL MISCELLANEOUS COMMANDS:
     I (Info) - Gives you details on the hardware, software and RF
facilities of the BBS you're using, or on some systems, a page of upcoming
events, helpful hints, or other useful information.

     J - Displays a listing of stations that were heard by the BBS or that
connected to the BBS.  Must be used with a port identifier, such as JA, JB,
etc.  J by itself will list the port IDs for you.

     M (Monitor) - Used for monitoring the activity on another port of the
BBS. Must be used with a port identifier, such as MA, MB, etc. M by itself
will list the port IDs.  (Not available on all systems.)

     B (Bye) - When you're finished using the BBS, you enter a B to
disconnect.

HELP DOCUMENT: Every BBS has help available for the user.  Simply enter an
H and follow the directions given.  In most cases, an H followed by a space
and then the letter of the command you want help on will give you the
specific information you need.  For example, if you wanted to know more
about the Download command, you would enter H D at the prompt.

There are other commands available that are specific to the particular
software being used.  Check your local BBS for a complete list of the
commands available to you.

- - - -

INTRODUCTION TO PACKET - PART 7 - by Larry Kenney, WB9LOZ

W0RLI, N6VV, and VE3GYQ have devised a scheme called HIERARCHICAL
ADDRESSING.  With hierarchical routing designators we have an opportunity
to improve traffic routing.  No longer will a missing call in a BBS
forwarding file cause a message to remain unforwarded, sysops will no
longer have to burn the midnight oil trying to keep their forward files
up to date, and messages will move much more directly toward their
destination.

The format for hierarchical routing is:
   addressee @ BBScall.#local area.state-province.country.continent.

It might look complicated, but it's not.  First, note that each section of
the format is separated by a period.  Codes used for the continents and
countries are standards, now accepted throughout the world.  You should be
able to find a list of them in the file section of your BBS.  State and
province codes are the recognized two-character codes established by the
American and Canadian Post Offices.  These may be found in the Callbook,
your phone directory, or any zip code listing.  Don't guess on the state
and province code if you aren't sure what it is, and make sure you use only
the two-letter abbreviation.  You could send the message to the wrong state
or province or keep it from being forwarded altogether.  The code for the
local area is optional, since most of you have no idea what code is being
used in upper New York state or in Iowa City, IA.  If you do know it,
please use it, since it will help get the message closer to where it's
going.  The code for Northern California is #NOCAL, and the code for
Southern California is #SOCAL.  You should use the appropriate one in the
signature line at the end of each message you send.  For messages going
outside of the US or Canada, the local area is again optional and the
state-province is not used.

Using the hierarchical format, here are some routing examples:
    WB9LOZ @ W6PW.#NOCAL.CA.USA.NA
    WB6LYI @ K6VE.#SOCAL.CA.USA.NA
    KC3XC @ N4QQ.MD.USA.NA
    VE3XYZ @ VE3RPT.ON.CAN.NA
    JA1ABC @ JA1KSO.#42.JPN.AS
    VK4AHD @ AX4BBS.AUS.OC

You'll note that the local area code is preceded by the octothorpe (now,
how's that for a $5 word?), better known as the number or pound sign.  The
reason is that the Japanese network, and possibly other areas, use routing
numbers for the local area, which could get confused with zip and postal
codes. Using the # on all local area codes will eliminate forwarding
problems.

We need to emphasize two very important points: hierarchical addressing
DOES NOT indicate a forwarding PATH, and ONLY ONE BBS call should be
included in the address.  A list of BBS calls separated by periods will not
get your message to its destination.  In fact, it can cause your message to
loop between BBSs and your message probably won't be delivered. The
addressing scheme is said to be one area inside another area.  Using my
hierarchical address as an example, WB9LOZ @ W6PW.#NOCAL.CA.USA.NA, here's
how you would describe the address: "WB9LOZ at W6PW which is in Northern
California which is in California which is in the USA which is in North
America".

There are several BBS programs that implement hierarchical addressing now,
including the W0RLI, WA7MBL, AA4RE, MSYS and WD6CMU software.  Check the ID
block you receive when you log into your BBS.  If it has an H in it, such
as [RLI-11.11-CH$] or [4RE-02.10-HM$], your system supports it.

USING THE HIERARCHICAL ADDRESS: This next section explains how the BBS
software uses the hierarchical addressing scheme.  We first have to
understand how the software goes about matching items in the "@ BBS"
address with items in the forward file.  For an example, let's say that we
send a message to Tom, W3IWI, who operates his own BBS and is located near
Baltimore, Maryland.  We would enter:
     SP W3IWI @ W3IWI.MD.USA.NA
If the only entries in the forward file are California BBSs plus a list of
state abbreviations, let's see how the message would be forwarded.  The
first thing the software does is attempt to find a match between the items
in the forward file and the left-most item in the address field.  In our
case, it would not find W3IWI.  If there isn't a match, it then moves to
the next section to the right.  It would find MD and that match would allow
the message to be forwarded.  If it had found the call W3IWI, that entry
would take precedence (because it is more left in the field than MD) and
would of course also ensure delivery.

Here are some comments from the ones who devised the hierarchical
addressing:

"There is another added benefit to this scheme.  It involves Gatewaying
between the BBS world and other networks, such as TCP/IP via SMTP.  Much of
the pioneer work in setting up the gatewaying protocols has been done by
NN2Z, N3EUA, and PA0GRI, amongst others.  The W0RLI BBS package allows for
the forwarding of mail between the BBS world and the SMTP world.  Of note
is the fact that the WA7MBL package has allowed such message exporting and
importing for some time now.  This means that we can take advantage of the
the TCP/IP host-names and their domain or hierarchal format for forwarding.
Thus it is possible to send mail from the BBS to VE3BTZ as
[e-mail] or from SMTP to [e-mail] and not
have any ambiguity.

"The authors hope that this paper will serve as a starting place for
improved message routing by means of implicit routing.  Low-level (VHF)
BBSs need only maintain state or province or country codes for distant
BBSs, and route such traffic to their nearest HF Gateway.  In turn, the HF
station routes it to the desired state, where the receiving Gateway station
would have a detailed list of the BBSs it serves."

Comments from W0RLI, N6VV and VE3GYQ.

- - - -

INTRODUCTION TO PACKET RADIO - PART 8 - by Larry Kenney, WB9LOZ

This part of the series discusses, in detail, the various parts of the
packet message.  The following is an example of what you see when listing
messages on a BBS.  On some systems the information is displayed in a
different order, but the same information is given.

 MSG# STAT SIZE TO     FROM   @ BBS  DATE/TIME SUBJECT
 4723 P    1084 WD5TLQ WA6XYZ N5SLE  0604/1240 Software working great!
 4721 BI    771 PACKET WB9LOZ ALLUSW 0604/1154 INTRODUCTION TO PACKET
 4717 BF   2387 EXAMS  W6NLG  ALLCAN 0604/1020 FCC Exams: June - Dec.
 4715 T     275 94114  W1AAR         0604/0959 QTC San Francisco 415-821
 4712 BF    918 ALL    N6ZYX  ALLCAN 0604/0845 9600 BAUD DEMONSTRATION

The MESSAGE NUMBER is assigned by the BBS program when the message is
received and it cannot be changed.  The numbers are assigned sequentially.

The STATUS of the message includes several different bits of information.
The first letter of the STATUS indicates the TYPE of message: B for
Bulletin, P for Personal, or T for Traffic for the National Traffic System.
Bulletins are messages of general interest to all users, and are available
to be read by everyone using the system.  Personal messages are listed only
for the sender and the addressee, and they're the only ones that can read
them.  (Anyone in monitor mode could see a personal message as it's being
sent over the air, of course.)  The list above would have to have been
requested by WA6XYZ since it lists an outgoing personal message.  Traffic
messages, type T, are messages used for handling traffic on the National
Traffic System.  (Refer to part 12 of this series for information on NTS.)

STATUS also shows if the message has been read, has already been forwarded
to all designated stations, is in the process of being forwarded, or is an
"old" message.  You might see one of these letters: Y - yes, it has been
read,  F - it has been forwarded,  I - it's in the process of being
forwarded right now on another port, or O - the message has been on the BBS
long enough to become an "old" message.  "Old" can be anywhere from 2 days
for an NTS message to 3 weeks for bulletins.  The time frame for each
message type is specified by the local sysop.  The "O" is mainly used to
catch the attention of the sysop.

The SIZE indicates the combined total of characters, including punctuation
in the message.

TO is who the message is addressed to or it can be a message category.  The
call of the addressee is entered for a personal message, and for bulletins
it could be ALL, EBARC, USERS, etc. TO is also used to categorize bulletins
by particular topics.  You might find a message addressed TO AMSAT, TO
PACKET or TO SALE, when it is actually a message about AMSAT, about PACKET
or about equipment for SALE.  For NTS messages TO is the zip code of the
addressee.

FROM shows the callsign of the station originating the message.

@ BBS is used if you want a message to be forwarded to someone at another
BBS or for general distribution using a forwarding designator. In the list
shown above, the personal message would automatically be forwarded to
WD5TLQ at the N5SLE BBS.  By entering a special designator, such as ALLCAN,
in the "@ BBS" column a message can be forwarded to specific areas.  (See
Part 6 and 7 of this series for details on addressing messages and using
forwarding designators.)

Next is the DATE and TIME when the message was received at the BBS you're
using.  (If the message was originated at another BBS, the date and time
when the message was originally entered will be shown in the forwarding
headers, as explained below, and at the top of the message when you read
it.)  Keep in mind that the date and time indicated can be either local
time or GMT (Zulu time) depending on the time used by the BBS.

The SUBJECT (or TITLE) is a short line telling what the message is all
about.  It should be brief, but informative.  For bulletin type messages,
this is the information that determines whether or not a person is going to
read your message when he sees it in the message list.

The parts of the message mentioned so far are all included in the header of
the message, and are seen when listing messages.  The hierarchical address
and the message ID are not shown in the normal listing.  On some systems,
such as those using W0RLI software, entering a semicolon after the list
command will give you this information.  (Example:  LL 15 ;)

If a message has been forwarded from another BBS, forwarding headers are
added at the top of the actual message text.  This is information added by
each BBS that was used to get the message from its origination point to the
destination.  Each BBS adds one line showing the time the message was
received by that particular BBS, its call sign, and usually the QTH, zip
code, and message number.  Other information is often added, at the
discretion of the sysop there.  If you use the RH command, rather than just
R, when reading a message, such as RH 7823, you'll receive complete
headers.  With just the R, headers are reduced to a list of the BBS
callsigns.  Complete headers are useful if you want details on the path the
message took to reach you or how long it took to be forwarded from system
to system from the source to destination.

The TEXT of the message contains the information you want to convey to the
reader.  It can be of any length.  When entering a message into a BBS, use
carriage returns at the ends of your lines, as if you were using a
typewriter.  The normal screen width is 80 characters, so you should enter
a carriage return prior to the 80th character on each line.  Don't allow
the automatic wrapping of lines to occur.  A message entered without
carriage returns is very difficult to read, as words are cut at improper
points, lines vary drastically in length, and blank lines are often
inserted.

You should include your name, call and packet address at the end of the
text so that the person reading your message will be able to send a return
message to you if he or she wishes to do so.

You complete the text with either a Control-Z or these three characters:
the "slash" (/) plus the letters "EX".  These characters must be on a line
by themselves.  On some systems only the Control-Z will work.  This tells
the system that you've finished entering the message.

Messages that are going to be forwarded to several BBSs or across a long
distance should be limited in size.  Extremely long messages can tie up the
forwarding system unnecessarily, so users are advised to break up long
messages into parts, keeping them to a length of 2 - 3 K each.

- - - - -

INTRODUCTION TO PACKET RADIO - Part 9 - by Larry Kenney, WB9LOZ

In this part we're going to look at the White Pages.  No, not your local
telephone directory, but the packet radio directory known as the "White
Pages".  You help supply the information for "WP", and you can also use it
to find the home BBS, QTH and zip code of your friends on packet.

"White Pages" was initially designed by Eric Williams, WD6CMU, of Richmond,
California.  Hank Oredson, W0RLI, later added a WP database to his packet
bulletin board software.  It's a database of packet users showing their
name, home BBS, QTH and zip code.  It's updated and queried by packet
message, allowing stations from all over the world to take advantage of it.
As users enter their name, home BBS, QTH and zip code into the BBS user
file, the software automatically assembles a message once a day containing
all of the latest user information and sends it to AD8I in Ohio, now the
national White Pages Server.  Systems in Northern California also exchange
this information.  As a result, you can easily find the name, home BBS, QTH
and zip code of other packet stations on packet all across the country
using the White Pages database.

If your BBS is operating with its own WP database, you may make inquiries
of it using the "I" command.  Simply enter I followed by the callsign you'd
like information about.  If you wanted information on WB9LOZ, for example,
you would enter: I WB9LOZ

Information from the WD6CMU or AD8I White Pages is obtained by sending a
message to "WP @ WD6CMU.CA" or "WP @ AD8I.OH".  Since the messages are read
and answered by the WP software, not a person, you must use the correct
format:  <callsign> QTH?  You may include as many requests as you wish in
one message, but each request must be on a separate line. The last line of
the message should be: DE <your_callsign> @ <Home_BBS> so that the response
is returned to you at your home BBS.  If the return address line is not
given, the WP program will attempt to determine the originating station and
BBS from the message headers.  If the requested information is not
available from the WP database, the return message will tell you so.

Here's an example of a message sent to the WD6CMU or AD8I White Pages
database:
(Your BBS prompt) W6BBS> SP WP @ WD6CMU.CA    (SP WP @ AD8I.OH would be
Enter subject of message: Query                used for the AD8I database.)
Enter text:
K9AT QTH?
WA6DDM QTH?
KC3XC QTH?
K3AKK QTH?
DE N6XYZ @ W6BBS
(Control Z)

Capital and lower case letters may both be used within the message.

Just like all other packet messages, messages addressed to WP are forwarded
from BBS to BBS toward their destination.  If a BBS operating with the
W0RLI WP Server handles a query message, it will respond with any pertinent
information that it has available.  As a result, you might receive more
than one response to your WP query.

The WP program also collects data from any WP responses it sees, as well as
from the headers of every message that passes through.  The information on
each call in a WP database is usually deleted in 60 to 90 days if it's not
updated.  This is determined by each local sysop.

It is important to note here that you should choose ONE BBS as your home
BBS, the one where you want all of your messages delivered.  Always enter
that callsign when you are asked to enter your home BBS, even if you are
using another system at the time.  When a message arrives at the BBS
destination given in the "@ BBS" column, some of the latest software will
check the White Pages information to make sure that the message has been
delivered to the right place.  If it finds that a different BBS is listed
as the addressee's home BBS, it will insert that BBS callsign in the
message and send it on its way.  If you enter different home BBS calls on
several BBSs, your mail could easily end up being sent from BBS to BBS and
never reach you.

If you move or change your home BBS, you should then make sure that you
update the information for your call in the White Pages database.  Use the
NH, NQ and NZ commands to update the information.  Making sure that the
information in the White Pages is correct will help to get your messages
delivered to the correct BBS.

- - - -

INTRODUCTION TO PACKET RADIO - PART 10 - By Larry Kenney, WB9LOZ

In this and the next part of the series we're going to take an in depth
look at the packet node network.  In part 4 of this series we explained how
to use the network for connecting to another station.  Now we'll look at
the other features a node offers.

A packet node, in most cases, is still set up for digipeater operation, so
you can still use it as a regular digipeater, but for most of your
connections you'll want to use the node features.  When using a string of
digipeaters, your packets have to reach their destination parity correct,
and the receiving TNC has to return an acknowledgement (ack) to your TNC
for each packet cycle to be completed.  As you add more digipeaters to the
string, the chances of this happening become less and less.  Other stations
on the frequency and noise can be the cause of many retries.  When using a
node, however, your packets no longer have to reach their destination
before acknowledgements are returned to your TNC.  Each node acknowledges
your packet as its sent along the way toward its destination.

Using the packet node network can make your operating time on packet more
enjoyable and it can greatly expand the area that you can reach.  The
network of NET/ROM, TheNet, G8BPQ and KAM nodes is expanding very quickly
and now covers most of the country.  New nodes are showing up almost daily.
Thanks to all of these stations and the interconnecting links, you can now
connect to stations in many far distant places using a low powered 2 meter
rig.  Some nodes are set up for cross-banding, and with the introduction of
nodes on 10 meter FM, there's the possibility of working a station just
about anywhere.

If you've been monitoring lately, you might have seen the nodes in action.
You might have wondered why they were sending all of those weird symbols
like @fx/<~|.  What you're seeing is the nodes communicating with each
other and updating their node lists.  You also might have noted callsigns
with high numbered SSIDs, such as WB9LOZ-14, WA6DDM-15, W6PW-12, etc.  The
nodes change the SSID of all stations so that the packets sent via the
network are not the same as those sent directly.  If you were to use a node
to connect to another station in the local area, there's the possibility of
your packets being received by this station both from you directly and from
the node. If the call through the node wasn't changed, the TNCs involved
would be totally confused as it would appear that two stations were
connecting using the same callsign.  The node automatically changes the
SSID using the formula 15-N, where N is your usual SSID.  A call with -0
becomes -15, a -1 becomes -14, -2 becomes -13, etc.

The node network is very simple to use.  As explained in part 4, to use the
node network, you first connect to a local node.  It should be one where
you can connect direct with good signal strength.  Once you've connected,
you then have several options -- connect to another station within range of
the node, connect to another node, connect to an associated BBS, obtain a
list of the nodes that are available, or check route and user status.  On
NET/ROM and TheNet nodes you can also answer or call CQ.

There are several commands available on your local node.  All have CONNECT,
NODES, ROUTES and USERS, and depending on the type of node you're using,
you might also find the BBS, BYE, CQ, INFO, PARMS or PORTS commands
available.

THE PACKET NODE COMMANDS:

CONNECT: The CONNECT command (which can be abbreviated as C) is used just
like you use the CONNECT command with your TNC.  To connect to another
local station using the node, simply enter C followed by the callsign.  To
connect to another node you can use either the callsign or the alias.  For
example, you can connect to W6AMT or you can connect to the alias SFO.
Either one will work.

There's a special consideration when making connections from a node using
the G8BPQ Packet Switch software.  Since these nodes are capable of having
several different frequencies connected to the one node, you have to
indicate which frequency port you want to make your connection on.  The
PORTS command, abbreviated P, will give you a list of the ports available,
such as this:
    SF:WB9LOZ-2} Ports:
        1 223.52 MHz
        2 144.99 MHz
        3 443.15 MHz
You then insert the port number between the C and the callsign, such as
C 2 W6RFN, to indicate which frequency you want to use, in this case the
port 2 frequency of 144.99 MHz.

NODES: The NODES command (which can be abbreviated as N) will give you a
listing of other nodes that can be worked from the node you're connected
to.  It lists both the alias and the callsign of each node it knows about.
The list you'll find on each node will vary in length and will contain
different callsigns since all of the frequencies are not linked.

(continued with more on the NODES command and other commands in part 11)

- - - -

INTRODUCTION TO PACKET - Part 11 - by Larry Kenney, WB9LOZ

THE NODE NETWORK - continued

The NODES command has another feature that gives you a simple way to find
out if another node is accessible and, if it is, the best route to use to
reach it. It's easy to make a quick check of the route quality to any other
node.  All you need to do is enter N followed by either the alias or
callsign of the node that you want to reach, such as:
      N FRESNO    or    N W6ZFN-2
You'll receive a report showing up to three routes to the node you asked
about, how good these routes are and how up to date the information is. If
there is no information available, you will receive either "Not found" or
the complete node list, depending on the type of node or switch you're
using.

Let's take a look at a typical report you would receive after entering
N FRESNO.  If you were connected to a NET/ROM or TheNet node the report
would look like this:
    SFW:W6PW-1} Routes to: FRESNO:W6ZFN-2
      105 6 0 WB9LOZ-2
      78 6 0 WW6L-1
      61 5 0 WA8DRZ-7
If you were connected to a G8BPQ packet switch you would see one less
column in the report and it would look like this:
    SF:WB9LOZ-2} Routes to: FRESNO:W6ZFN-2
    > 126 6 W6PW-10
      61 3 WW6L-1
      60 4 W6PW-1
Each line is a route to the node you asked about.  The symbol > indicates a
route that's in use.  The first number is the quality of the route.  255 is
the best possible quality and means a direct connect via hard wire to a
coexisting node at the same site; zero is the worst, and means that the
route is locked out.  192 is about the best over the air quality you'll
find, and it usually means that the node is only one hop away.  If you see
a quality of less than 80, you'll probably have a difficult time getting
any information through via that route.  The second number is the
obsolescence count.  This number is a 6 when the information for this route
is less than an hour old.  For each hour that an update on the route is not
received, this number is decreased by one.  A 5 means the information is an
hour old, a 4 means that it's two hours old, and so on. The next number,
shown only on NET/ROM and TheNet nodes, indicates the type of port.  A 0 is
an HDLC port; a 1 is an RS-232 port.  You don't need to pay any attention
to this figure.  The callsign is that of the neighboring node that's next
in line on the route.  Digipeaters are shown if any are used to reach this
neighboring node.

This quick check on a node that you want to reach can save you a lot of
time.  You'll know immediately whether or not the node is available, and if
it is, how good the available routes are to it.  You then won't have to
spend time trying to connect to a node that isn't available or is of poor
quality.

If you find that there's a decent route to the node or switch you want to
reach, it's normally best to let the network make the connection for you.
Simply enter a connect to the alias or callsign you want rather than
connecting to each individual node along the route yourself.

If a route exists but the quality is not very good, you might want to
connect to the neighboring node shown for the best route, then do another
quality check, repeating this procedure until you find a route with decent
quality.  You can actually get through to some distant nodes using this
method if you have the time and patience to work on it.

ROUTES: The ROUTES command (abbreviated as R) will give you a list of the
direct routes available from the node you're using to other nodes.  These
are the nodes seen directly by the node you're using.  The quality of each
route is shown along with the obsolescence count, as explained above.  Any
route marked with an exclamation point (!) means that the route values have
been entered manually by the owner of the node and usually means that the
route is not reliable for regular use.

USERS: The USERS command (which can be abbreviated as U) will show you the
calls of all the stations using the node you're connected to.  There are
five descriptions used by the node to describe how users are connected:
   UPLINK: The station indicated is connected directly to the node.
   DOWNLINK: The node has made a connection from the first station to the
      second station.  Example:  DOWNLINK (K9AT-15 N6UWK)  would mean
      that the node connected to N6UWK at the request of K9AT.
   CIRCUIT: Indicates that the station has connected from another node.
      It shows the alias and call of the other node prior to the user's
      call.  Example:  Circuit (SFW:W6PW-1 WA6DDM) would mean that WA6DDM
      is using this node, but he connected to it from the SFW:W6PW-1 node.
   CQ: See "CQ" below.
   HOST: The user is connected directly from the node terminal.  This is
      seen when the owner of the node is a user, or the BBS associated with
      the node is using it to forward messages.

CQ COMMAND: The CQ command (which cannot be abbreviated) is used for
calling CQ, and it also can be used for replying to the CQ of another
station.  The CQ command is available only in the latest version of NET/ROM
and TheNet.

Using the CQ Command:  The CQ command is used to transmit a short text
message from a node, and is also used to enable stations that receive the
transmission to connect to the station that originated it.  The command is
entered as:   CQ [textmessage]
The "textmessage" is optional and can be any string up to 77 characters
long (blanks and punctuation are allowed).  In response to a CQ command,
the node transmits the specified textmessage in "unproto" mode, using the
callsign of the originating user with a translated SSID as the source and
"CQ" as the destination.  For example, if user station W6XYZ connects to a
node and issues the command: "CQ Anybody around tonight?", the node would
then transmit "W6XYZ-15>CQ: Anybody around tonight?"

After making the transmission in response to the CQ command, the node
"arms" a mechanism to permit other stations to reply to the CQ.  A station
wishing to reply may do so simply by connecting to the originating call-
sign shown in the CQ transmission (W6XYZ-15 in the example above).  A CQ
command remains "armed" to accept replies for 15 minutes, or until the
originating user issues another command or disconnects from the node.

Any station connected to a node may determine if there are any other
stations awaiting a reply to a CQ by issuing a USERS command.  An "armed"
CQ channel appears in the USERS display as:
    (Circuit, Host, or Uplink) <~~> CQ(usercall).
The station may reply to such a pending CQ by issuing a CONNECT to the user
callsign specified in the CQ(...) portion of the USERS display--it is not
necessary for the station to disconnect from the node and reconnect.

Here's what a typical transmission would look like: (* = entered by user)
*  cmd: C KA6YZS-1
   cmd: *** Connected to KA6YZS-1
*  USERS
   501SJC:KA6YZS-1} NET/ROM 1.3 (669)
   Uplink(WB9LOZ)
   Uplink(K1HTV-1)            <~~>  CQ(K1HTV-14)
   Circuit(LAS:K7WS-1 W1XYZ)  <~~>  CQ(W1XYZ-15)
   Uplink(N4HY)
*  CONNECT W1XYZ-15
   501SJC:KA6YZS-1} Connected to W1XYZ
*  Hello!  This is George in San Jose
   Hi George!  Thanks for answering my CQ.   etc.

Users of the CQ command are cautioned to be patient in waiting for a
response.  Your CQ will remain "armed" for 15 minutes, and will be visible
to any user who issues a USERS command at the node during that time.  Wait
at least five minutes before issuing another CQ to give other stations a
chance to reply to your first one!

BBS: The BBS command is available on nodes using the G8BPQ software where
an associated packet bulletin board system is operational.  Entering BBS
will connect you to the associated BBS.

BYE: The BYE command is available on G8BPQ nodes and is used for
disconnecting from the node.  It does the same thing as disconnecting.

IDENT: The IDENT command, found on NET/ROM nodes, will give you the
identification of the node you're using.

INFO: The INFO command, found on TheNet and G8BPQ nodes, will give you
information about the node, usually the alias, callsign and location.

PARMS: The PARMS (Parameters) command, found on NET/ROM nodes, is for the
owner's use in determining how his station is working.

- - -

INTRODUCTION TO PACKET RADIO - PART 12 - by Larry Kenney, WB9LOZ

The National Traffic System, known as NTS, is the ARRL sponsored Amateur
Radio message handling network.  Packet radio is now playing a very
important part in the network, so let's take a look at the system and
give you some tips on handling NTS traffic by packet.

Handling third party traffic is the oldest tradition in amateur radio.
Nationwide, the National Traffic System has hundreds of local and section
nets meeting daily in order to facilitate the delivery and origination of
such messages.  More and more of this traffic is being originated, relayed,
and delivered on packet.  If you enjoy traffic handling, you can easily get
involved in NTS via packet.  If you're on packet but know nothing about
NTS, this part of the series will get you off to a good start.  At the end
you'll also find some references for further information on NTS.

Local packet BBSs have to be checked daily for traffic that needs to be
delivered or relayed.  When you check into your local BBS, enter the LT
command, meaning "List Traffic".  The BBS will sort and display a list of
all NTS traffic awaiting delivery.  It'll look similar to this example:

 MSG# STAT SIZE TO     FROM   @BBS   DATE/TIME SUBJECT
 7893 T     486 60625  KB6ZYZ NTSIL  1227/0712 QTC1 CHICAGO, IL 312-267
 7802 T     320 06234  K6TP   NTSCT  1227/0655 QTC1 NEW HAVEN, CT
 7854 T     588 93432  KA4YEA        1227/0625 QTC1 CRESTON, CA 93432
 7839 T     412 94114  KK3K          1227/0311 QTC1 SAN FRANCISCO 415-821
 7781 T     298 94015  W1KPL         1226/2356 QTC1 DALY CITY, CA 415-992

You might see traffic that is being relayed by your local BBS to some other
part of the country as well as traffic for your local area. The "Subject"
or "Title" column of the listing will show the destination of the traffic.
If you see a message that is within your local area, help out and deliver
it.

RECEIVING A MESSAGE: To take a message off of the Bulletin Board for
telephone delivery, or for relay to a local NTS net, enter R followed by
the message number.  Using the list above, R 7839 would send you the
message from KK3K for San Francisco.  You'll find the message in a special
NTS RADIOGRAM format, with a preamble, address, telephone number, text and
signature, ready for delivery.  After the message has been saved to your
printer or disk, the message should be erased from the BBS.  You use the KT
command, which means "Kill Traffic", followed by the message number.  In
this case you would enter KT 7839 to erase the message you took from the
BBS.  This prevents the message from being delivered again by someone else.

DELIVERING OR RELAYING A MESSAGE: Once you have received the NTS Radiogram,
it should, of course, be handled expeditiously.  If it's for your immediate
area, you should deliver the message by telephone.  If you took the message
for delivery to the local traffic net, you should make an effort to see
that it gets relayed as quickly as possible.

SENDING MESSAGES: Any amateur can originate a message on behalf of another
individual, whether the person is a licensed amateur or not.  It is the
responsibility of the originating amateur, however, to see that the message
is in proper form before it's transmitted.  A special format is used for
NTS traffic so that the messages are compatible across the entire network.
Each message should contain the following components in the order given:
number, precedence, handling instructions (optional), the station of
origin, check, place of origin, time filed, date, address, telephone
number, text and signature.

When the message is ready to be entered into your local BBS, you must use
the ST command, which means "Send Traffic", followed by the zip code of the
destination city, then @ NTS followed by the two letter state abbreviation.
The form used is ST ZIPCODE @ NTSxx.  A message being sent to Boston, MA
02109 would be entered as follows:  ST 02109 @ NTSMA and a message for Iowa
City, IA 52245 would be entered as ST 52245 @ NTSIA.  The message SUBJECT
or TITLE should contain "QTC 1" followed by the destination city and state
and the telephone area code and exchange, if available.  See the examples
in the listing above.  Only one NTS message should be included in each
packet message.  The actual radiogram should be included entirely within
the TEXT of the packet message, including all of the components listed
above.  End the message with the usual Control-Z.

IN TIME OF EMERGENCY: The National Traffic System functions on a daily
basis as a public service for both your fellow hams and the general public.
It serves another function as well.  The NTS provides a well oiled and
trained national system of experienced traffic handlers able to handle
large volumes of third party traffic accurately and efficiently during
disasters.  At least that is the goal.

REFERENCE MATERIAL:  The ARRL booklet "An Introduction to Operating an
Amateur Radio Station" offers detailed information on handling and
preparing NTS Radiograms.  The file "HOWTO.NTS" gives a complete rundown
on how to prepare and send an NTS message on packet.  Check your local BBS
files section for it.  You should also find several other files such as
"DELIVERY.NTS" and "WHATIS.NTS" that will provide you with a wealth of
information.  Check them out if you want to get involved.  Your help will
be welcome!

- - -

INTRODUCTION TO PACKET RADIO - Part 13 - by Larry Kenney, WB9LOZ

In this part of the series we'll take a look at many of the TNC commands
available to you that we haven't covered in previous articles.  We will be
discussing the commands used in the TAPR TNC2 and TNC2 clones.  You might
find that some of the commands are not available in your particular TNC or
that they're used in a slightly different manner than the one explained
here.  Please refer to your owner's operating manual for specific details
on how to use these commands in your TNC.

8BITCONV:  This command enables the transmission of 8-bit data in
converse mode.  Used with AWLEN - see below.  For normal packet operation,
such as keyboard to keyboard transmissions, use of bulletin boards, and
transmission of ASCII files, 8BITCONV should be OFF.  If you need to
transmit 8-bit data, set 8BITCONV ON and set AWLEN to 8.  Make sure that
the TNC at the receiving end is also set up this way.  This procedure is
normally used for transmission of executable files or a special non-ASCII
data set.

AWLEN:     This parameter defines the word length used by the serial
input/output port of your TNC.  For normal packet operation, as described
above, AWLEN should be set to 7.  Set to 8 only if you're going to send
8-bit data.

AX25L2V2:  This command determines which level of AX.25 protocol you're
going to use.  If OFF, the TNC will use AX.25 Level 2, Version 1.0.  If ON,
the TNC will use AX.25 Level 2, Version 2.0.  Note: Some early TNCs will
not digipeat Version 2.0 packets.  With AX25L2V2 OFF, if your TNC sends a
packet and the packet doesn't get acknowledged the first time it was sent,
it will send it again and again, until an "ack" is received or the TNC
retries out.  With AX25 ON, if your TNC sends a packet and doesn't receive
an "ack" the first time, it will send a poll frame to see if the other TNC
received the packet.  If yes, then it would continue, if not then it would
send the last packet again.  The advantage here is that short poll frames
are sent, rather than long packets containing data.  This can greatly
reduce channel congestion.  For VHF/UHF operation, it is almost essential
that every TNC have AX25L2V2 ON.  Many operators have suggested that
Version 2.0 NOT be used on the HF bands as it tends to clutter the
frequency with poll frames.  See the CHECK command below for related
information.

BEACON:    Used with EVERY or AFTER to enable beacon transmissions.
   BEACON EVERY n  -  send a beacon at regular intervals specified by n.
   BEACON AFTER n  -  send a beacon once after a time interval specified
                      by n having no packet activity.
n = 0 to 250  -  specifies beacon timing in ten second intervals.
                 1 = 10 seconds, 2 = 20 seconds, 30 = 300 seconds or
                 5 minutes, 180 = 1800 seconds or 30 minutes, etc.
For example, if you set BEACON EVERY 180 (B E 180), the TNC will transmit a
beacon every 30 minutes.  If you set BEACON AFTER 180 (B A 180), the TNC
will transmit a beacon after it hears no activity on the frequency for 30
minutes.  B E 0 will turn the beacon off. The text of the beacon is
specified by BTEXT and can contain up to 120 characters.  The path used for
the beacon transmission is specified by the UNPROTO command.  YOU SHOULD
USE BEACONS INTELLIGENTLY!  Beacons are often a point of controversy in the
packet community because they tend to clutter the frequency if used too
frequently.  You should keep your beacons short and infrequent, and they
should only be used for meaningful data.  Bulletin boards use the beacon
for advising the community of who has mail waiting for them, clubs use
beacons for meeting announcements, beacons are used for weather warnings,
etc.

CHECK n    Sets a timeout value for a packet connection.  Operation
depends on the setting of AX25L2V2.  The value of CHECK (n) determines the
timing.  Value may be 0 to 250.  Check set to 0 disables the command. If a
connection between your station and another exists and the other station
seems to "disappear" due to changing propagation or loss of an intermediate
digipeater, your TNC could remain in the connected state indefinitely.  If
the CHECK command is set to a value other than 0, the TNC will attempt to
recover.  The setting of AX25L2V2 will determine what action is taken. If
AX25L2V2 is ON, the TNC will send a "check packet" to verify the presence
of the other station if no packets have been heard for n * 10 seconds.
(n = 1 = 10 seconds, n = 5 = 50 seconds, n = 30 = 5 minutes, etc.)  If a
response is received, the connection will remain.  If no response is
received, the TNC will begin the disconnect sequence, just as if the
DISCONNECT command had been sent.  If AX25L2V2 is OFF, after no packets are
heard for n * 10 seconds, the TNC will not send a check packet, but will
begin the disconnect sequence.

CMSG       Enables the automatic sending of a connect message whenever a
station connects to your TNC.  If CMSG is ON, the TNC will send the message
contained in CTEXT as the first packet of the connection.  CTEXT can
contain up to 120 characters.  This feature is often used when the station
is on but the operator is not present.  The connect message is used to
advise the other station of that fact, and often says to leave a message in
the TNC buffer.  If CMSG is off, the text message is not transmitted.

KISS       KISS enables the TNC to act as a modem for a host computer,
allowing programs such as TCP/IP, the G8BPQ Packet Switch, various BBS
programs, and other programs using the Serial Link Interface Protocal
(SLIP) to be run.  Before turning KISS on, set the radio baud rate and
terminal baud rate to the desired values.  Set KISS to ON and then issue a
RESTART command.

                                        (continued in part 14)

- - - -


INTRODUCTION TO PACKET - Part 14 - by Larry Kenney, WB9LOZ

TNC COMMANDS - continued from Part 13

MAXFRAME   Sets the upper limit on the number of unacknowledged packets the
TNC can have outstanding at any time.  (The outstanding packets are those
that have been sent but have not been acknowledged.)  It also determines
the maximum number of contiguous packets that can be sent during one
transmission.  Value can be set from 1 to 7.  The best value of MAXFRAME
depends on the frequency conditions.  The better the conditions are, the
higher the value you can use.  If conditions are poor due to the amount of
traffic on the frequency, noise, or other variables, (shown by lots of
retries) MAXFRAME should be reduced to improve throughput.  The best value
of MAXFRAME can be determined through experimentation.  MAXFRAME of 1
should be used for best results on HF packet.

MFILTER     This command allows you to enter up to four ASCII character
codes, 0 - $7F, for the control characters that you want eliminated from
your monitored packets.  Codes may be entered in either Hex or Decimal.
Here are the ASCII codes for some of the more troublesome control
characters found in monitored packets:
   HEX   DEC   FUNCTION   POSSIBLE RESULT
   $07    07   Control G  Rings your bell or "beeps" your speaker
   $0C    12   Control L  Form feed - could clear your screen
   $13    19   Control S  Can cause your screen to stop scrolling
   $1A    26   Control Z  Can clear your screen
   $1B    27   Escape     Can cause your cursor to move to a random
                          point on your screen and can raise havoc
                          with printer control.
AEA has added a new code, $80, that will not allow ANY control characters
to be displayed on the user's screen from monitored packets.

MHEARD     An immediate command that causes the TNC to display a list of
stations that have been heard since the command MHCLEAR was given or the
TNC was powered on. This command is useful for determining what stations
can be worked from your QTH.  Stations that are heard through digipeaters
are marked with an * on most TNCs.  On the AEA PK-232, the stations heard
direct are marked with the *.  (Check your TNC manual.)  The maximum number
of stations in the list is 18.  If more stations are heard, earlier entries
are discarded.  Logging of stations heard is disabled when the PASSALL
command is ON.  If the DAYTIME command has been used to set the date and
time, entries in the MHEARD list will show the date and time the stations
were heard.

PASSALL    Causes the TNC to display packets that have invalid checksums.
The error-checking is disabled.  If PASSALL is ON, packets are accepted for
display, despite checksum errors, if they consist of an even multiple of
eight bits and are up to 330 bytes.  The TNC attempts to decode the address
field and display the callsigns in standard format, followed by the text of
the packet.  PASSALL can be useful for testing marginal paths or for
operation under unusual conditions.  PASSALL is normally turned OFF.

SCREENLN n This parameter determines the length of a line of text on the
terminal screen or platen.  Value may be 0 to 255.  A (CR-LF) carriage
return and line feed are sent to the terminal in Command and Converse modes
when n characters have been printed.  A value of zero inhibits this action.
If your computer automatically formats output lines, this feature should be
disabled.

TXDELAY n  This parameter tells the TNC how long to wait before sending
data after it has keyed the transmitter. All transmitters need some start
up time to put a signal on the air.  Some need more, some need less.
Synthesized radios and radios with mechanical relays need more time, while
crystal controlled radios and radios with diode switching require less
time.  External amplifiers usually require additional delay.  Experiment to
determine the best value for your particular radio.  TXDELAY can also be
useful to compensate for slow AGC recovery or squelch release times at the
distant station.

There are many additional commands available to you.  I've only covered the
ones that I thought would be the most useful to you.  Spend some time
reading the owner's operating manual that came with your TNC to discover
some of the surprises the other commands offer.  New versions of the TNC
software have added several commands that you might find useful in your
packet operating.

- - - -


INTRODUCTION TO PACKET RADIO - Part 15 - by Larry Kenney, WB9LOZ

Here are some tips to help make your packet operating more enjoyable.
Whether it's while making local QSOs, checking into a BBS or mailbox, or
working DX, there are a few things you should take into consideration that
will help eliminate problems and waiting time and will increase your
throughput.  ("Throughput" is a word that has come into use by packet
operators that means the amount of usable packet information received by
the distant station.)

When connecting to another station, don't use a digipeater or node unless
you have to.  Each digipeater you add to the path increases the time
required to get your signal to its destination and to get an acknowl-
edgement returned.  It also increases the chance for interference and for
collisions with other packets.  You'll be amazed at the difference in
throughput when comparing a direct connect to one with just one digipeater
in the path.

The packet node network, as discussed in previous articles in this series,
does a great deal to help you get your packets through, but you must
remember that throughput there, too, is affected by the number of nodes and
the conditions between you and the destination station.  The big advantage
of the nodes is that the acknowledgements do not have to return all the way
from the destination station.  Packets are acknowledged from node to node,
so that eliminates a large part of the problems encountered.  Getting the
original packet through, however, remains to be as much of a problem for
the nodes as it is for you when using digipeaters.  It can take several
minutes to get a packet through when you're working a station some distance
away.

Dr. Tom Clark, W3IWI, has determined that for EACH HOP in a packet path the
loss of packets can vary anywhere from 5% to 50% depending on the amount of
traffic.  Remember, each digipeater and node adds a hop, so multiply those
percentages by the number of hops, then multiply by 2 to account for the
acknowledgement, and you can see how quickly the path deteriorates as
traffic increases and digipeaters and nodes are added to it.

If you have a choice, use a frequency that doesn't have a lot of other
traffic on it.  It makes sense that the more stations there are on
frequency, the more chances there are for collisions and retries.  A path
that will work perfectly without a lot of traffic, can become totally
useless under heavy traffic conditions.  Just one additional station on
the frequency can decrease throughput by about half in many cases.

Another consideration, especially if working over a long distance, is
atmospheric conditions.  You might not have experienced this before on VHF,
but with packet's high sensitivity to noise, a slight change in signal
strength can mean the difference between getting your packets through or
not getting them through.  An example of one path that is very vunerable to
conditions due to its distance is from W6AK-1 on Mt. Vaca to WB6AIE-1 on
Bald Mountain in Yosemite National Park on 145.05 MHz.  Most of the time,
packets go between these two nodes without any problem, but there are
times, especially when it's a hot summer day in the Sacramento Valley, when
it's impossible to get a packet from one to the other.  In the Bay Area,
the fog has a drastic affect on VHF signals.  When a fog bank is moving in
off the Pacific, it can act as an excellent reflector.  Signals that are
not normally heard can reach signal strengths of 40 over S9.

Multipath is another problem that can greatly affect your packet signal.
Multipath is the term used to describe the receipt of multiple signals from
one source due to reflections off of buildings, hills or mountains.  The
"ghost" in a television picture is a form of mutipath.  A station with a
very strong signal into a digipeater or node often cannot use that path if
multipath causes the signal to be distorted.  Each packet is checked for
100% accuracy and is not acknowledged unless it is.  Multipath reflection
can cause occasional bits to be lost so you end up with multiple retries
and a poor path even with strong signals.

To sum up, for best results on VHF use the least number of digipeaters and
nodes as possible, use a frequency with low activity, and be aware of
atmospheric conditions and multipath problems.

If you use packet on HF, remember to change your transmit baud rate to 300
and to use a short PACLEN (a value of 40 seems to work quite well) and a
MAXFRAME of 1.  The chances of getting a short packet through the noise and
QRM are much better than for a long one.

_ _ _


INTRODUCTION TO PACKET RADIO - PART 16 - by Larry Kenney, WB9LOZ

In this article, let's do some reviewing.  I'm going to present a short
quiz on packet, covering the basics that I've presented in the past 15
parts.  Let's see how well you can answer the following questions without
looking back at the past articles.  In Part 17 I'll discuss each question
and give you the correct answers.

1. What are the three TNC modes of communication?
    a. Connect, Converse, Terminal
    b. Command, Converse, Terminal
    c. Command, Converse, Transparent
    d. Command, Connect, Transparent

2. What TNC command is used to set the transmit path for beacons and CQs?

3. What is the TNC command CHECK used for?

4. While you're connected to another station, what command is used to
   monitor other traffic on the frequency?

5. If you saw one of the following lines on your screen when in monitor
   mode, what would the asterisk indicate?
      W6ABC-3>N6XYZ,W6PW-1*: Hi Bob
      W6ABC-3>W6PW-1*>N6XYZ: Hi Bob
   (Displays vary with various TNCs, so both common types are shown.)

6. Why does the packet node network improve communications?

7. If you're connected to a station in New Mexico using the node network,
   how do you disconnect?

8. If N6ZYX-2 connected to you via a node, what would the SSID of the
   station become at your end of the connection?

9. When you're connected to another station, what are the two most
   probable causes for packets not to be received by the other station?

10. There are several basic commands used on a packet bulletin board
    system.  Indicate what you would enter to perform the following:
      a. Receive a list of messages.
      b. Download a file in the General (ID G) directory called
         FCCEXAMS.89.
      c. Enter a private message to Jim, WA6DDM, who uses the W6PW BBS
         in San Francisco, California.
      d. Read message 7134 with complete forwarding headers.
      e. Find out what stations have been heard by the BBS on port B.

11. To send an NTS message via packet addressed to Tom Smith, 123 Main
    Street, Keene, NH 03431, telephone [phone], what would you
    enter at the BBS prompt?

12. If a message has a STATUS of BF, what does that indicate?

13. If you received a message from a friend in Chicago that had been
    forwarded to your home BBS through four other BBSs and the message
    had a Date/Time of 0316/2245 when you listed it, which of the
    following is a TRUE statement?
      a. The message was written at 2:45 pm on March 16.
      b. The message was entered into the BBS by your friend at 2245
         on March 16.
      c. The message was forwarded by your friend's BBS in Chicago at
         2245 on March 16.
      d. The message was received at your home BBS at 2245 on March 16.

14. If you wanted to send a message to your friend John, W4IP, but you
    didn't know what the call of his home BBS was, what could you do to
    try and find out what the call is?

15. What is the maximum value for MAXFRAME?  If you're working a station
    on 30 meters and are sending a lot of retries, should you increase or
    decrease MAXFRAME?

Well, how did you think you did?  We'll take a look at the answers to these
questions and more in part 17.

- - - -

INTRODUCTION TO PACKET RADIO - PART 17 - by Larry Kenney, WB9LOZ

How did you do on the review quiz in the previous part of this series?
If you haven't taken it, you might want to read part 16 and take the quiz
now before reading any further.

Here are the correct answers and the series part numbers where you can
read more about the subject:

1 - Answer C is correct.  The three TNC modes of communication are Command,
Converse and Transparent.  Command mode is for communicating with the TNC.
The Converse mode is for normal QSOs, connects to a BBS or mailbox, etc.
and Transparent mode is used for binary file transfer.  (Part 2)

2 - The UNPROTO command is used for setting the transmit path for both
beacons and CQs. (Parts 3 and 13)

3 - The CHECK command is used for setting a timeout value in your TNC.
If set to a value other than zero, the TNC will attempt to recover a
connection after a certain specified time if nothing is received from the
other station.  This command is used in combination with the AX25L2V2
command.  (Part 13)

4 - The MCON command (Monitor while CONnected) is used to monitor other
traffic on the frequency while you're connected to another station.
(Part 3)

5 - When monitoring, the asterick indicates the station that you actually
hear the packet from.  The MRPT command must be ON for the monitor display
to show digipeaters.  (Part 2 and 3)

6 - The packet node network improves communications because packets are
acknowledged from your station to the first node, and then node to node
to the destination.  A packet doesn't have to reach the destination
before an ack is returned.  (Parts 4, 10 and 11)

7 - When using the node network (no matter who you're connected to) you
disconnect by going to command mode on your TNC and entering a D, just like
at other times.  The fact that you're using several nodes or are connected
to a distant station makes no difference.  The network will take care of
disconnecting all stations and links.  (Parts 4, 10 and 11)

8 - N6ZYX-2 would appear as N6ZYX-13 if he connects to you using a node.
The nodes change the SSID using the formula 15-N.  (Part 10)

9 - The two most probable causes for a packet not to get through are
collisions with other packets on the frequency and noise due to weak
signals.  (Part 15)

10 - BBS commands:
  a. To receive a list of messages: enter L
  b. To download a file in the General (G) directory called
     FCCEXAMS.89, you'd enter DG FCCEXAMS.89
  c. To enter a private message to Jim, WA6DDM: SP WA6DDM @ W6PW.CA
     (The "@ W6PW" is not needed if you're using the W6PW BBS.)
  d. To read message 7134 with headers: RH 7134
  e. To find out what stations were heard on port B of the BBS, you'd
     enter JB
 (Parts 5, 6, 7 and 8)

11 - If you wanted to send an NTS message to Tom Smith, 123 Main Street,
in Keene, NH  03431, you would enter the following at the BBS prompt >
ST 03431 @ NTSNH               (Parts 6 and 12)

12 - A message with a STATUS of BF means that the message is a bulletin
and that it has been forwarded to all stations that are supposed to
receive it from the BBS you're using.   (Part 8)

13 - Answer D is correct.  The date/time shown on a message when it's
listed is the time the message was received at the BBS you're using.
Please note that the date/time of a message indicates whatever time the
BBS your using is set to, and that could be local time or zulu time, UTC,
GMT, or whatever.  Most BBSs are now set to zulu time (UTC, GMT), but a
few still use local time.  When you read a message, you should be able to
read the date and time the message was written from the message header.
  (Part 8)

14-To find the call of the HOME BBS of your friends, use the White
Pages Directory.  If the BBS you're using has the WP feature enabled,
you will find the I command to be useful, otherwise send an inquiry
to WP.  (Part 9)

15-The maximum value for MAXFRAME is 7.  MAXFRAME is the number of packets
transmitted by your TNC contiguously, and the number of unacknowledged
packets the TNC can have outstanding.  You decrease MAXFRAME when the
conditions are poor.  Your TNC will send fewer packets at one time, so
there will be less information to collide with other packets on the
frequency and less chance of information being wiped out by noise.
(Part 14)

There is no passing grade on the quiz.  It was designed for you to check
your general packet knowledge, and you'll have to be your own judge of that.
I hope you did well on it!

- - - -


INTRODUCTION TO PACKET RADIO - PART 18 - by Larry Kenney, WB9LOZ

In the previous 17 parts of this series, I have attempted to cover all of
the basics of packet radio - from setting up your TNC and making your first
QSO, to using digipeaters, the packet node network, bulletin board systems
and mailboxes.  Many of the TNC commands have been explained, including the
best settings for normal packet use, and I've offered suggestions that
should make it easier and more enjoyable for you to use packet radio.

Changes in packet are made quite frequently as new versions of the software
for the TNC, node network and bulletin boards are released.  Try to be
aware of these changes so that you can take advantage of the latest infor-
mation.

Now you might want to investigate some of the newer developments in packet
radio.  There are several programs available for making special use of
packet, such as the Packet Cluster software used by the DX Spotting Net-
works, TCP-IP, Tex-Net, Conference Bridging, etc.  PAC-SAT, the packet
satellite program, is growing in popularity as more satellites carrying
packet radio equipment are released.  High speed modems running at speeds
of up to 56 kilobaud are just around the corner for general use.  You'll
find a wide variety of special interests available to you.

I'd like to thank the following for help in preparing this series: Don
Simon, NI6A; Bill Choisser, K9AT; Don Fay, K4CEF; Scott Cronk, N7FSP; and
Hank Oredson, W0RLI.

If you have any comments on this "Introduction to Packet", or if you have
any questions on the topics discussed, want to suggest new topics for
inclusion in future articles, or want to correct or update any of the
information contained in the series, please send a packet message to me.
Your comments will be appreciated.  I hope that you've found the series to
be informative and helpful in making packet more enjoyable for you.

73, Larry Kenney, WB9LOZ @ W6PW.#NOCAL.CA.USA.NA

- - - -