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EI2GYB > PACKET 23.11.18 08:32l 132 Lines 7126 Bytes #999 (0) @ WW
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Subj: INTRODUCTION TO PACKET RADIO - PART 3
Path: IW8PGT<IR2UBX<IW2OHX<UA6ADV<LU4ECL<GB7CIP<EI2GYB
Sent: 181123/0727Z @:EI2GYB.DGL.IRL.EURO #:2172 BPQ6.0.16
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 or packet software to help improve your station operation.
The TNC (Terminal Node Controller) has more than 100 different commands
available 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 set of
commands. I'll be using the command set in the TNC2 and clones in my
examples. You might want to check the command list in your TNC operating
manual to see if your TNC uses the commands as I indicate here.
For those of you who are using the packet software and modem instead of a
TNC, you'll find a list of the commands in your help documentation. You
will find that some of the commands cannot be modified while the software
is running. Some have to be changed with the program's configuration file.
Check the help document for instructions on how to change these commands
in your particular software.
We covered a few of the commands previously: CONTROL C for entering command
mode, MYCALL, MONITOR, ECHO, CONNECT, and DISCONNECT. (Refer to Part 2 if
you need information on these commands.) Now let's discuss a few that will
affect the way your station functions on the air.
CONV (converse mode): Your TNC will automatically switch to this mode
when you connect with someone, but you can also switch to this mode by
entering CONV <CR> at the Cmd: prompt. When you're in converse mode and
are NOT connected to another station, anything you type will be transmitted
via the path you set with the UNPROTO command. (See the next paragraph for
UNPROTO.) Packets sent via UNPROTO are sent only once and are not acknowl-
edged, so there is no guarantee that they'll get through. This mode is
used frequently for sending CQ's.
UNPROTO: Designates the path used when you send BEACONS or when you're in
converse mode and NOT connected to another station. 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
If you include digipeaters in your UNPROTO path, you will have to change the
information for each frequency you use. (BEACONS will be discussed in a
later part of this series.)
FRACK: Determines how long your TNC will wait for an acknowledgement
before resending a packet. It shouldn't be set too low, or you'll simply
clutter up the frequency, yet it shouldn't be too high, or you'll spend too
much time waiting. I use FRACK set to 7, and have found that to be a good
overall 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: Indicates the number of characters in the packets you transmit,
ranging from 0 to 255. (A value of 0 equals 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 0 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. Do NOT set
RETRY to 0. That means infinite retries, and serves no useful purpose. It
simply clutters up the frequency needlessly.
The following commands affect "monitoring", which is what you see on your
screen from stations you're NOT connected to.
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 only see the packets that are sent to you while you're connected to
another station.
Note: On some TNCs, such as the AEA PK-232, monitoring functions are
selected by a number after the MONITOR command, such as MONITOR 3 or M 3.
Refer to your TNC operating manual for details.
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 or SABM>, 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 asterisk 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: The date and the time the monitored packets are received is
indicated if the MSTAMP command is ON. If it's OFF, the date/time stamp
is not shown. NOTE: The date and time must be entered into your TNC memory
using the DAYTIME command before the MSTAMP command will function.
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.
MORE COMMANDS - The commands discussed here are a few of the basic TNC
commands. I'll discuss many of the other commands available to you in
Parts 13 and 14 of this series.
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