World of Ham Radio 1997/WOHR97_AmSoft_(1997-02-01).iso/packet/docs/packet03.doc

Text File | 1997-02-01 | 6KB | 115 lines

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.

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