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How to Work ISS Chat Room, Short Version



April 13, 2001

G. Miles Mann

Short Version

How to use the Unproto (Chat Room) Amateur Radio System on ISS

Working the International Space Station ISS on 2-meter packet station is
easier than you may think.  I have been able to connect to the ISS
packet station on a regular basis with a very modest 2-meter base
station and from my car packet station.  The name of the 2-meter packet
experiment on the ISS is the "Personal Message System" or PMS.  The ISS
PMS experiment  is specifically designed to allow easy access to
beginners.  If you have an existing 2-meter packet station at home now,
then you may already have all of the equipment you need to start a
friendship with the Cosmonauts and Astronauts on board ISS.

In this article I will describe the equipment you need to operate the
ISS (International Space Station Alpha).  I will also discuss the
features supported by the PMS and cover the setup details for operating
the Unproto mode called Chat Room.   Other modes will be covered in
separate memos.

The ISS is currently using an Erickson portable radio (known as a HT)
which is operating on the Amateur Radio 2-meter band.  The Personal
Message System is using a 1200 baud Terminal Node Controller (called a
TNC or Packet or Modem) from Paccom.  The radio is currently connected
to a pair of externally mounted co-phased mono band antennas
(2-meters).  The typical power output is 3 watts, with an ERP rating of
1.5 watts. 

To work ISS from your home, you should have at least the following
Amateur Radio equipment.  A 2-meter radio with an output rating of 25 to
50 watts or more.  An omni-directional antenna or small beam.  A short
run of good quality coax (RG-213, 100 feet or less).  And a standard
1200 baud AX.25 Packet modem (TNC). I use an inexpensive KPC-3 modem for
all of my ISS packet connections.

 
TNC Configuration:

NOTE:  ONLY UNPROTO IS ACTIVE THIS WEEK, AKA CHAT ROOM.
THE ISS CALL SIGN IS TEMPOARALY "NOCALL", IT WILL BE CHANGED
LATER TO "R0ISS"

To operate the ISS PMS, you will need to modify some of the settings on
your TNC.  Most of the parameter changes required for ISS will be
compatible with terrestrial BBS operations.  Using these suggested
parameters will improve you're connection rate and at the same time help
reduce QRM.  Note, ARPS settings will be covered in a different memo. 
This memo is for Unproto and Email settings.  You do not need APRS to
work ISS Email or Unrproto (Chat Room)

This is a portion of the TNC parameters in my KPC-3; your actual
parameters may vary:
AUTOCR			OFF
BEACON			OFF
LFADD			OFF
MAXFRAME			4
MCON	 		ON
MCOM			ON
MONITOR 			ON
PACLEN			72
RETRY			8-10
TIME STAMP		ON
Unproto			CQ V R0ISS 

BEACON:	
Make sure your beacon is disabled.  Unattended beacons on the ISS packet
uplink will just cause interference.  You should only transmit manually
while you are at controls.
There has been a lot of email about the settings for using beacons. 
Please keep beacons turned OFF, while on the ISS uplink channel.  Only
call ISS Chat Room Manually !!!!

LFADD:  
This value seems to interfere with normal ISS BBS operations.  Make sure 
LFADD is turned OFF.

MCON:
Set this value on to monitor all data.

MCOM: 
This value is normally turned "OFF" for terrestrial BBS connections and
"ON" for connections to the ISS PMS.  This value will allow you to see
packets going to other stations, while you are Connected or Attempting
to Connect.  All courteous operators using ISS will keep this value
ON.    

MONITOR:
Allows monitoring of packets while not connected.

PACLEN:  
Lots of short packet lengths are less likely to be clobbered than a few
very long packets.  

RETRY: 
You do not want to set this value too high because you may cause QRM
during your initial connect.  Also, if "RETRY" is too short, you will
time-out during the one of the 4 deep RF signal fades.  
Foot note 2.  During a 10 minute pass, there will be 4 RF polarity
shifts in the signal coming from ISS. This shift is caused by the
apparent position of the antenna on ISS's in relation to your antenna. 

TIME STAMP:  
With Time Stamp turned on, you will be able to log data to your disk
while you are away and track the time and duration's of the passes.

Unproto:
The unproto command has two parts.  The first part can be any six (6)
letters of your choice.  Most people use CQ or a grid square location. 
The second part is the letter V or VIA, the third part is the call sign
of the Digi.  This week the call sign of ISS is NOCALL.  
Now with the correct parameters configured, you will be able to monitor
all of the data coming from the ISS PMS.  The packet data you see will
typically fall into one of the 6 categories listed below.  Please test
first on a terrestrial digi first.

U CQ V NOCALL

C-Connect request
D-Disconnect request 
DM-Disconnect mode 
UA-Unnumbered Acknowledge 
UI-Unconnected Information frame
I(n)-Information frame (n=0-7).


ISS and Packet UnProto mode  or Chat Room

The ISS PMS (Personal Mail System) also supports the Digital repeating
mode called UnProto / Chat Room.  I am not going to get into too much
detail about UnProto / Chat Room, for more information check Amateur
radio hand books and back issues of Amateur Radio magazine.  Basically
UnProto / Chat Room is a way of sending packet messages without
requiring an acknowledgment from the other station.  This mode is
similar to RTTY in that, you can have several stations in one big QSO at
the same time.  Set your UnProto command in your TNC, on my KAM the
syntax is "U CQ V NOCALL".  Then switch to Converse mode (enter K at
cmd: prompt).  Now everything you type will be transmitted in UnProto
Mode.  If the ISS station hears your transmission, the ISS PMS Digi will
rebroadcast your information with a range of over a 1000 miles.   Below
is a short UnProto / Chat Room between a station in Massachusetts and
Pennsylvania, using the ISS Digi Chat Room.  The stations were arranging
to meet on HF when the ISS pass was over.

N3CXP>CQ,NOCALL*:Hi all, great sigs here! de Tom in Allentown, PA

WF1F>FN42,NOCALL*:n3cxp are u on

N3CXP>CQ,NOCALL*:HI miles

WF1F>FN42,NOCALL*:i have the amp on hf 7.215

N3CXP>CQ,NOCALL*:just copying the mail

N3CXP>CQ,NOCALL*:ok cu after the pass

WF1F>FN42,NOCALL*:I dub thee ISS Chat room

N3CXP>CQ,NOCALL*:just copying the mail, here miles

WF1F>FN42,NOCALL*:ok tom

WF1F>FN42,NOCALL*:monitoring 7.215 lsb

The UnProto mode does not guarantee you message will ever be heard, but
if the ISS Digi does rebroadcast your line of text, then you can be
assured that someone saw it.  The line of text you send will be repeated
with an Asterisk after it, "R0ISS*/".  If you do not see the Asterisk,
then ISS did not hear your packet.  UnProto does have its drawbacks, but
it is much more efficient to use on ISS than the Direct two-way connect
method. Full two-way packet connects via the ISS PMS are not recommended
because they use up too much resources and excessive "Retires".  Before
you try Unproto on ISS, I recommend that you practice on a Terrestrial
Digi first before attempting to use the ISS station for Digi-repeating.
If you make a few UnProto calls and do not get any echo's back from ISS,
it is probably because the band is too busy, wait and try later. 

Packet frequency with Doppler correction

Chan Receive 		Transmit 	Offset (Meg)
145.802.5 		145.988.5 	+0.186  first 1/3 of pass
145.800.0 		145.990.0 	+0.190  Middle of pass
145.798.5 		145.992.5 	+0.194  End of pass

New MAREX Web pages:
Check out our future ISS Projects and a large list if Mir related links

www.marex-na.org

Copyright 2001 Miles Mann, All Rights Reserved.  This document may be
freely
distributed via the following means - Email (including listservers),
Usenet,
and World-Wide-Web.  It may not be reproduced for profit including, but
not
limited to, CD ROMs, books, and/or other commercial outlets without
prior
written consent from the author.

Until we meet again

DOSVIDANIYA Miles WF1F
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