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Re: PMS usage suggestions?




I have mounds of log data from the MIR Space Station I could present
to show that 1 minute is not a realistic time frame to do much of
anything with a single user PBBS connection interface. The TNC on
MIR was always busy sending rejecting frames to those stations trying
to connect while another station was already connected. This takes
time from the connected user who is trying to accomplish their goal
while connected to the PBBS.

We cannot rely on the human interface to make this work. History tells
us it did not happen in all the years the PBBS flew on MIR. Why would
that change now? If we do not accept that reality, we are only fooling
ourselves and continuing the same type of activity. Rules imposed on
the human interface will not fix the perceived problem.

Solving the problem is a goal, but is there really a problem. Unless
the purpose and goals of the TNC flying on ISS are clearly defined, then
we do not know if a problem really exists. So, I took a step back and
visited the ARISS web page and attempted to review the mission and
goals for digital communications and found them to be general in
nature.

http://ariss.gsfc.nasa.gov


After reading the posted material, the following thoughts came to
mind:

The PBBS is not suitable for general Amateur Radio operation. This
could be a perception, but from the numbers of comments on the
topic over the years I accept it as the reality.

However, the PBBS can serve the ISS crew very well when used on
alternate frequencies.

A dedicated computer is needed to expand experimental operation
and to expand the capabilities of the currently installed TNC.

For expanded BBS operation supporting more than one user there
are several BBS packages like FBB and other programs that would
support multiple users very easily, thereby eliminating the time
consumed by the TNC sending rejection frames to subsequent users
wishing to connect to the BBS. These alternate BBS packages allow
multiple users to connect. I am not advocating this method, because
I feel the connected packet mode is not the appropriate choice for
mass communications if that is the intent.

For expanded messaging capability much like a BBS, there are
software packages utilizing the unconnected packet mode of
operation like APRS (Automatic Position Reporting System). These
provide a tactical communications system that is more efficient
than the BBS mode of operation that uses the connected packet
mode of operation. These systems offer more flexibility in allowing
ground based stations to marry both RF connections and Internet
connections to provide continuity when RF line of sight operations
are not possible. A series of strategically located Internet Gateway
systems expand the communications system beyond the RF line
of sight. This system allows messaging capability so that messages
can be sent and between users as well as the ISS crew.  It offers
more flexibility than an antiquated PBBS system, but it does
require a dedicated computer to collect the messages. Perhaps,
this could be a long term goal. It also offers the ISS crew a way
to send Internet EMAIL via the APRS mechanism. Now there
might me an added benefit.




73's,

Tim - N8DEU
Huntsville, Alabama





> On 3 Mar 2002, Scott Avery wrote about time to Access the PBBS on ISS:
>
> > That is a good question! Considering optimum conditions, and no QRM
it
> > would take about 2 minutes.  This includes the connection time,
listing,
> > and reading, then disconnecting.  That would exceed a 1 minute rule.
>
> Actually, I think it can be done much faster if the station is ready
to
> go.  I think  well under a minute, but I only suggested a minute as a
> round number that everyone could remember.  Of  course "most" stations
> will have ZERO success in the actual operating conditions and should
not
> even try so that others who do have a chance can get in-and-off in
such a
> short time.






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